installation manual
Collins General Aviation Division
Collins WXR-840
Advanced
Weather Radar System
523-0775822-00111A
1st Edition, 28 April 1991
installation manual
Collins WXR-840
Advanced
Weather Radar System
This publication includes:
General Information
Installation
Operation
Theory of Operation
Maintenance
523-0775823
523-0775824
523-0775825
523-0775826
523-0775827
Collins General Aviation Division
Avionics Group
Rockwell International Corporation
Cedar Rapids, Iowa 52498
Printed in the United States of America
Caution
The material in this publication is subject to change. Before
attempting any maintenance operation on the equipment covered
in this publication, verify that you have complete and up-to-date
publications by referring to the applicable Publications and
Service Bulletin Indexes.
We welcome your comments concerning this publication. Although
every effort has been made to keep it free of errors, some may occur.
When reporting a specific problem, please describe it briefly and include
the publication part number, the paragraph or figure number, and the
page number.
Send your comments to:
Publications Department
Collins General Aviation Division
Rockwell International Corporation
Cedar Rapids, Iowa 52498
SPECIFIC ADVISORIES FOR THE WXR-840
Warning
Electronic control systems, such as autopilots, engine controls, fuel controls, temperature sensors, etc,
used for aircraft control can be susceptible to transmissions from communications transceivers, DME’s,
transponders, etc, that can interfere with aircraft operations. If such a situation occurs, discontinue
transmission or select a different frequency. If necessary, turn off the radio.
Warning
The area within the scan arc and within 5 metres (15 feet) of an operating WXR-840 Weather Radar
System constitutes a hazardous area. Do not operate the system in any mode other than standby
(STBY) or test (TEST) when the antenna might scan over personnel within that range. Never turn on
the transmitter while in a hanger. FAA Advisory Circular 20-68B, or superseding documents, provide
additional details regarding the radiation hazards associated with ground operation of airborne weather
radar.
GENERAL ADVISORIES FOR ALL UNITS
Warning
Service personnel are to obey standard safety precautions, such as wearing safety glasses, to prevent
personal injury while installing or doing maintenance on this unit.
Warning
Use care when using sealants, solvents, and other chemical compounds. Do not expose to excessive heat
or open flame. Use only adequate ventilation. Avoid prolonged breathing of vapors and avoid prolong
contact with skin. Observe all cautions and warnings given by the manufacturer.
Warning
Remove all power to the unit before disassembling it. Disassembling the unit with power connected is
dangerous to life and may cause voltage transients that can damage the unit.
Warning
This unit may have components that contain materials (such as beryllium oxide, acids, lithium,
radioactive material, mercury, etc) that can be hazardous to your health. If the component enclosure
is broken, handle the component in accordance with OSHA requirements 29CFR 1910.100 or superseding
documents to prevent personal contact with or inhalation of hazardous materials. Since it is virtually
impossible to determine which components do or do not contain such hazardous materials, do not open
or disassemble components for any reason.
Warning
This unit exhibits a high degree of functional reliability. Nevertheless, users must know that it is not
practical to monitor for all conceivable system failures and, however unlikely, it is possible that
erroneous operation could occur without a fault indication. The pilot has the responsibility to find such
an occurrence by means of cross-checks with redundant or correlated data available in the cockpit.
i
GENERAL ADVISORIES FOR ALL UNITS (cont)
Caution
Turn off power before disconnecting any unit from wiring. Disconnecting the unit without turning
power off may cause voltage transients that can damage the unit.
Caution
This unit contains electrostatic discharge sensitive (ESDS) components and ESDS assemblies that can
be damaged by static voltages. Although most ESDS components contain internal protection circuits,
good procedures dictate careful handling of all ESDS components and ESDS assemblies.
Obey the precautions given below when moving, touching, or repairing all ESDS components and units
containing ESDS components.
a. Deenergize or remove all power, signal sources, and loads used with the unit.
b. Place the unit on a work surface that can conduct electricity (is grounded).
c. Ground the repair operator through a conductive wrist strap or other device using a 470-kΩ or 1-MΩ
series resistor to prevent operator injury.
d. Ground any tools (and soldering equipment) that will contact the unit. Contact with the operator’s
hand is a sufficient ground for hand tools that are electrically isolated.
e. All ESDS replacement components are shipped in conductive foam or tubes and must be stored in
their shipping containers until installed.
f. ESDS devices and assemblies, that are removed from a unit, must immediately be put on the
conductive work surface or in conductive containers.
g. Place repaired or disconnected circuit cards in aluminum foil or in plastic bags that have a layer of,
or are made with, conductive material.
h. Do not touch ESDS devices/assemblies or remove them from their containers until they are needed.
Failure to handle ESDS devices as described above can permanently damage them. This damage can
cause immediate or premature device failure.
ii
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
RECORD OF TEMPORARY REVISIONS
ΝΟΤΕ: This page replaces the pink Record of Addendums page and follows the advisories pages. Addendums are printed on pink paper.
TEMPORARY
REV NO
PAGE NUMBER
Addendum 1
1-5
Sep 23/94 Rockwell Collins May 12/95 Rockwell Collins
Addendum 1 sheet 1
2-21
Aug 6/92 Rockwell Collins
Addendum 1 sheet 2
5-6
Aug 6/92 Rockwell Collins
Addendum 2
Advisory page i
Apr 29/94 Rockwell Collins
Addendum 2 sheet 1
1-5
May 12/95 Rockwell Collins
Addendum 2 sheet 2
2-6
May 12/95 Rockwell Collins
Addendum 3 sheet 1
1-1
May 30/98 Rockwell Collins
Addendum 3 sheet 2
1-2
May 30/98 Rockwell Collins
Addendum 3 sheet 3
1-3
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1-7
May 30/98 Rockwell Collins
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2-54
May 30/98 Rockwell Collins
Addendum 5
4-8
May 30/98 Rockwell Collins
Addendum 6
2-39
May 21/99 Rockwell Collins
Addendum 7
2-29
May 24/99 Rockwell Collins
Temporary Revision 8
523-0775822-08111A
DATE
ISSUED
BY
DATE
REMOVED
BY
Feb 2/01
Rockwell Collins
Feb 2/01
Rockwell Collins
RTR-1
Feb 2/01
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
RECORD OF TEMPORARY REVISIONS
ΝΟΤΕ: This page replaces the pink Record of Addendums page and follows the advisories pages. Addendums are printed on pink paper.
TEMPORARY
REV NO
PAGE NUMBER
8
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Feb 2/01 Rockwell Collins
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Feb 2/01 Rockwell Collins
Temporary Revision 8
523-0775822-08111A
DATE
ISSUED
BY
DATE
REMOVED
BY
RTR-2
Feb 2/01
ADDENDUM 3
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet facing page 1-1
of the General Information Section (523-0775823-001118)
This addendum adds the WXA-850A Weather Radar Adapter option to the WXR-840 radar system.
Add the following paragraph in Section 1.1.1 General Description immediately following the first paragraph.
An optional use of the WXR-840 system is to use the WXA-850A Weather Radar Adapter for direct information
interpretation on EFIS. This system consists of the RTA-84X Receiver/Transmitter/Antenna and the WXA-850A.
The WXA-850A converts the RTA output into TTL format for use on the EHSI displays. RTA control is through a
Control Display Unit (CDU). Refer to the WXA-850A CMM (523-0776543) for more details.
Addendum 3
30 May 1998
523-0775822-03111A
Sheet 1 of 4
(Facing Page 1-1)
I
section
general information
1.1 INTRODUCTION
This publication provides description, equipment
specification, installation instructions, operating
procedures, and information necessary for on-aircraft maintenance of the WXR-840 Advanced
Weather Radar System.
1.1.1 General Description
The WXR-840 system is a second generation
solid-state weather radar system. The system
consist of two separate units: the RTA-84X Receiver/Transmitter/Antenna and the WXP-840A/B
Weather Radar Panel. Refer to Figure 1-1. EFIS
displays are used to display the radar presentation.
The distinguishing feature of the RTA-84X unit
is its 1-piece design combining the receiver,
transmitter, and antenna into a single unit.
Refer to Figure 1-2. The forward portion of this
unit is the flat-plate antenna, which is available
in either 12-, 14-, or 18-inch-diameter models.
The antenna size is the primary distinguishing
feature between the RTA-842 (12-inch antenna),
RTA-844 (14-inch antenna), and RTA-848 (18inch antenna) models.
Directly behind the
antenna and attached to it is the RF assembly,
consisting of the transmitter and receiver. This
design eliminates the need for a waveguide. The
RF (receiver/transmitter/antenna) assembly is
mounted on the drive assembly and therefore
swings from left to right as the system scans and
up and down for tilt. The drive assembly
WXR-840 Advanced Weather Radar System, Overall View
Figure 1-1
28 April 1991
1-1
ADDENDUM 3
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet facing page 1-2
of the General Information Section (523-0775823-001118)
Add following paragraph just before Paragraph 1.2 Purpose of Equipment.
The optional WXA-850A has no controls or indicators. Refer to the WXA-850A CMM (CPN (523-0776543) for
more details.
Addendum 3
30 May 1998
523-0775822-03111A
Sheet 2 of 4
(Facing Page 1-2)
general information 523-0775823
RTA-84X Major Subassemblies
Figure 1-2
contains the motor and gears for the scan and tilt
functions and is attached to the base assembly.
The base assembly is cylindrical in shape, about
15 inches in diameter and slightly less than 2
inches in depth. It serves as the mounting base
and contains the power supplies and signal
processing portion of the RTA-84X unit. The
complete RTA-84X assembly must be mounted on
a forward bulkhead or radar antenna mounting
surface and be enclosed by a radome. For best
proper performance of any radar system the
radome should be at least 90 percent RF transparent.
The WXP-840A (panel mount) or WXP-840B
(Dzus mount) Weather Radar Panel provides the
operating control functions. This unit is normally mounted in the instrument panel and occupies
a space about 1½ inches high by 6¼ inches wide
for the WXP-840A, and 1 7/8 inches high by 5¾
inches wide for the WXP-840B. The control functions include MODE, GAIN, TILT, and RANGE
selection knobs, plus pushbuttons for ground
clutter suppression (GCS), slave mode (SLV),
28 April 1991
stabilization enable/disable (STB) selection, HLD
(display hold), AUTO (autotilt), and SEC (sector
scan).
1.2 PURPOSE OF EQUIPMENT
The WXR-840 Advanced Weather Radar System
provides the flight crew with a display of radardetectable precipitation within 60 degrees of the
flight path. Users must recognize that X-band
weather radar can detect only wet precipitation.
That is, precipitation like snow and some hail,
which is typically dry, is generally not detectable
by X-band radar.
1.3 EQUIPMENT SPECIFICATIONS
Table 1-1 is listing of the units that make up the
WXR-840 system. The table also shows the various models available with their individual Collins
part numbers. Table 1-2 is a listing of system
and LRU (line replaceable unit) specifications.
1-2
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
WXR-840 Advanced Weather Radar System
INSTALLATION MANUAL (523-0775822, 1ST EDITION, DATED APR 28/91)
TEMPORARY REVISION NO. 08
Insert facing page 1-3.
This temporary revision supersedes sheet 3 of Addendum 3.
Subject: Add equipment, note, and revise text
Add RTA equipment to Table 1-1, WXR-840 Equipment Covered. A note is also added to the table.
Changes are in bold text.
P/O Table 1-1. WXR-840 Equipment Covered
EQUIPMENT
RTA-842
RTA-844
RTA-848
14-INCH
ANTENNA
FLAT PLATE
18-INCH
ANTENNA
FLAT PLATE
LOW SPEED
ARINC 429 (50
kBD) DIGITAL
STABILIZATION
HIGH SPEED
ARINC 429 (100
kBD) DIGITAL
STABILIZATION
AUTOTILT
AND
TARGET
ALERT
ENABLED
COLLINS
PART
NUMBER
12-INCH
ANTENNA
FLAT PLATE
622-9301-001
X
X
622-9301-002
X
X
X
622-9301-003
X
X
X
X
622-9301-004
X
X
X
X
622-9301-011
X
X
X
622-9302-001
X
X
622-9302-002
X
X
X
622-9302-003
X
X
X
X
622-9302-004
X
X
X
X
622-9302-011
X
X
X
622-9303-001
X
X
622-9303-002
X
X
X
622-9303-003
X
X
X
X
622-9303-004
X
X
X
X
622-9303-011
X
X
X
NOTE: Information on the WXA-850A can be found in the WXA-850A CMM (523-0776543).
Change the first sentence of Paragraph 1.5 Storage to read as follows:
“The RTA-84X, WXP-840A/B and WXA-850A should be stored in its original packing materials and
shipping container.”
Temporary Revision 8
523-0775822-08111A
Page 1 of 9
Feb 2/01
general information 523-0775823
Table 1-1. WXR-840 Equipment Covered.
1.4 RELATED PUBLICATIONS
Table 1-3 lists publications related to WXR-840
operation.
1.5 STORAGE
The RTA-84X and WXP-840A/B should be stored
in its original packing materials and shipping
container. If the unit is to be stored for a long
28 April 1991
period of time, put the unit in an airtight plastic
bag with sufficient desiccant to absorb moisture.
At no time should the ambient temperature of the
storage area fall below -55 °C (-67 °F) or rise
above +85 °C (+185 °F). The relative humidity
should never exceed 95 percent. If the unit is
stored for an extended period of time, retest the
unit prior to returning it to service to ensure that
possible component degradation has not affected
performance.
1-3
general information 523-0775823
Table 1-2. Equipment Specifications.
CHARACTERISTICS
FAA TSO
SPECIFICATIONS
-C63c dated 18 August 1983
RTCA documents
RTA-84X
DO-160B, DO-178A, DO-173, class 7 (with change no 1 dated 25 January 1985)
WXP-840A/B
DO-173, DO-160A, DO-178A
Category
*
RTA-84X
F2/BB/JN/E1/XXXXXA/BZ/AZAZA
WXP-840A/B
D1/A/PKS/XXXXXXAAAAA
Size
RTA-842
RTA-844
RTA-848
Diameter
381 mm (15.0 in)
381 mm (15.0 in)
238.25 mm (18.76 in)
Depth
223.42 mm (8.8 in)
223.11 mm (8.8 in)
297.16 mm (11.7 in)
9.14 kg (20.1 lb)
9.23 kg (20.3 lb)
10.73 kg (23.6 lb)
WXP-840A
WXP-840B
Body
35.2 mm (1.39 in)
44.5 mm (1.75 in)
Bezel
37.6 mm (1.46 in)
47.6 mm (1.88 in)
Body
156.5 mm (6.16 in)
127.0 mm (5.0 in)
Bezel
158.8 mm (6.25 in)
146.1 mm (5.75 in)
Body
176.1 mm (6.93 in)
165.1 mm (6.5 in)
Overall
200.4 mm (7.89 in)
189.5 mm (6.6 in)
Mating connector depth
50.8 mm (2.0 in)
50.8 mm (2.0 in)
0.86 kg (2.0 lb)
0.86 kg (2.2 lb)
Weight (maximum)
Size
Height
Width
Length
Weight (maximum)
Maintenance requirements
On condition
Power requirements
RTA-84X
27.5 V dc
*
Standby
3.4 A max
Operate
3.8 A max
115 V ac, 400 Hz
10 mA max, or
26 V ac, 400 Hz
(for analog stabilization only)
2.3 mA max
Size dimensions are maximum when azimuth and tilt angles are equal to 0°.
28 April 1991
1-4
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
WXR-840 Advanced Weather Radar System
INSTALLATION MANUAL (523-0775822, 1ST EDITION, DATED APR 28/91)
TEMPORARY REVISION NO. 08
Insert facing page 1-4.
Subject: Revise equipment specification as shown below in bold text.
P/O Table 1-2. Equipment Specifications.
CHARACTERISTICS
FAA TSO
SPECIFICATIONS
-C63c dated 18 August 1983
RTCA documents
RTA-84X
DO-160B, DO-178A, DO-173, class 7 (with change no 1 dated 25 January 1985)
WXP-840A/B
DO-173, DO-160A, DO-178A
Category
RTA-84X
F2/BBJ/E1/XXXXXZ/AZAZAX
WXP-840A/B
D1/A/PKS/XXXXXXAAAAA
Temporary Revision 8
523-0775822-08111A
Page 2
Feb 2/01
ADDENDUM 2
TO
GENERAL INFORMATION SECTION (523-0775823-001118)
Located in the
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTRUCTION BOOK
523-0775822-00111A, 1st Edition, dated 28 April 1991
Insert this addendum facing page 1-5
in the General Information Section, 1st Edition,
dated 28 April 1991
This addendum sheet supersedes Addendum 1 sheet 1 of 1, dated 23 September 1994.
At the next revision to this manual, Table 1-2, Equipment Specifications, will be revised to correct the
transmitted output frequency and pulse width specification as follows:
Table 1-2. Equipment Specifications
CHARACTERISTIC
SPECIFICATIONS
Transmitted output
Frequency
X-band
9343.85 ±1.8 MHz transmit
9338.85 ±1.8 MHz preheat on units without SB 19
9336.85 ±1.8 MHz preheat on units with SB 19
Pulse length
Varies from 1.7 to 28.8 µs depending on range and mode as follows:
Range
Mode
Pulse length
5
MAP
1.7 µs
10
MAP
2.4 µs
25
MAP
4.8 µs
50
MAP
9.6 µs
100
MAP
19.2 µs
200
MAP
28.8 µs
300
MAP
28.8 µs
5
WX
2.4 µs
10
WX
4.8 µs
25
WX
9.6 µs
50
WX
19.2 µs
100
WX
19.2 µs
200
WX
28.8 µs
300
WX
28.8 µs
Changes are shown in bold text.
Addendum 2
12 May 1995
523-0775823-021118
Sheet 1 of 4
(Facing page 1-5)
ADDENDUM 1
TO
GENERAL INFORMATION SECTION (523-0775823-001118)
Located in the
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTRUCTION BOOK
523-0775822-00111A, 1st Edition, dated 28 April 1991
Insert this addendum facing page 1-5
in the General Information Section, 1st Edition,
dated 28 April 1991
At the next revision to this manual, Table 1-2, Equipment Specifications, will be revised to correct the
transmitted output frequency and pulse width specification as follows:
Table 1-2. Equipment Specifications
CHARACTERISTIC
SPECIFICATIONS
Transmitted output
Frequency
X-band
9345.85 ±1 MHz transmit
9338.85 ±85 MHz preheat on units without SB 19
9336.85 ±85 MHz preheat on units with SB 19
Pulse length
Varies from 1.7 to 28.8 µs depending on range and mode as follows:
Range
Mode
Pulse length
5
MAP
1.7 µs
10
MAP
2.4 µs
25
MAP
4.8 µs
50
MAP
9.6 µs
100
MAP
19.2 µs
200
MAP
28.8 µs
300
MAP
28.8 µs
5
WX
2.4 µs
10
WX
4.8 µs
25
WX
9.6 µs
50
WX
19.2 µs
100
WX
19.2 µs
200
WX
28.8 µs
300
WX
28.8 µs
Addendum 1
23 September 1994
523-0775823-011118
Sheet 1 of 1
(Facing page 1-5)
general information 523-0775823
Table 1-2. Equipment Specifications.
CHARACTERISTICS
SPECIFICATIONS
WXP-840A/B
27.5 V dc
0.5 A max
Lighting
27.5 V dc
0.35 A, or
5 V ac/dc
1.5 A
Transmitted output
Power
24 Watts nominal
Frequency
X-band (9343.85 ±1 MHz preheat and 9338.84 ±1 MHz transmit)
Pulse length
1.7, 2.4, 4.8, 9.6, 19.2, 28.8 µs
Pulse repetition rate
208 to 324 pps in WX modes
100, 200, or 300 nmi
252 to 390 Hz
5, 10, 25, or 50 nmi
1461 to 2209 Hz
Duty factor
0.0015 to 0.03
Receiver
IF bandwidth
Less than 500 kHz
First IF
406 MHz
Second IF
33.8 MHz
MDS
-128 dBm nominal
STC
Dynamic: Optimized for range and pulse width
Environmental
RTA-84X
DO-160B
Pressure altitude
Cat F2: Nonpressurized to 55 000 ft, uncontrolled temperature environment
Operating temperature
Cat B: -55 to +70 °C
Humidity
Cat B: Severe humidity environment, level I
Shock
6 g/11 ms, operational 15 g/11 ms, crash safety
Vibration
Cat J: Turbojet; fuselage mounted
Cat N: Helicopter; rack mounted
Explosion
Cat E1: Capable of operation in a flammable or explosive environment but not
intended for insulation in that environment
Magnetic effect
Cat A: 0.3 to 1.0 meter for 1° deflection
Power input
Cat BZ: Aircraft power with ac power generation with or without a battery floating
on the dc bus, +18- to +29.5-V dc operation, capable of surge operation at +40 V dc,
abnormal surges to +80 V dc for 100 ms
Voltage spike
Cat A: Installations requiring very high tolerance to voltage spikes
AF susceptibility
Cat Z: Aircraft with ac power generation with or without a battery floating on the
dc bus
Induced susceptibility
Cat A: Interference- free operation
28 April 1991
1-5
general information 523-0775823
Table 1-2. Equipment Specifications.
CHARACTERISTICS
SPECIFICATIONS
RF susceptibility
Cat Z: Interference-free operation
Electromagnetic interference
Cat A: Interference- free operation
WXP-840A/B
Pressure altitude
15 200 m (50 000 ft)
Temperature
Operate
Continuous
-20 to +55 °C (-4 to +131 °F)
Short term
Up to +70 °C (+158 °F)
Storage
-55 to +85 °C (-67 to +185 °F)
Humidity
DO-160A Cat A
Vibration
Frequency
5 to 17 Hz
0.2 in, da
17 to 37 Hz
3.0 g peak
37 to 55 Hz
0.02 in, da
55 to 70 Hz
0.75 g peak
70 to 500 Hz
0.5 g peak
500 to 2000 Hz
0.25 g peak
Cooling
Antenna
Convection
12 inch
14 inch
18 inch
Beam width
8°
7°
6°
Gain
27.5 dB
28.9 dB
30.5 dB
*Avoidance range
280 nmi
296 nmi
358 nmi
*Performance index
217.6
219.0
223.6
Data bus format
Data output
ARINC 453
Data input
ARINC 429
Stabilization
Analog
2-wire gyro synchro 50 or 200 mV/°
Digital
ARINC 429 (50 kBd) (installations with IAPS)
ARINC 429 (100 kBd) (RTA-84X -002 status only)
Scan rate
28 April 1991
27°/second, approx 14 scans/min (120°), approx 4.9 seconds/scan
1-6
ADDENDUM 3
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet facing page 1-7
of the General Information Section (523-0775823-001118)
Add new Table 1-2A after Table 1-2 Equipment Specifications.
Table 1-2A. Optional Equipment.
EQUIPMENT
WXA-850A
PART NUMBER
DESCRIPTION
822-0053-001
Weather Radar Adapter
827-5060-001, or
628-9865-001
Standard mount
Mount modified with capture screw [preferred]
(WXA-850A requires 2 mounts for proper
installation)
Control Adapter Mount
Add information to Table 1-3 Related Publications as follows: (Addition in bold)
Table 1-3. Related Publications
PUBLICATION
COLLINS PART NUMBER
Collins WXA-850A Weather Radar Adapter Component Maintenance Manual
523-0776543
Addendum 3
30 May 1998
523-0775822-03111A
Sheet 4 of 4
(Facing Page 1-7)
general information 523-0775823
Table 1-2. Equipment Specifications.
CHARACTERISTICS
SPECIFICATIONS
Selectable modes
OFF
STBY (standby)
TEST (self-test)
TGT (target alert)
MAP (ground mapping)
WX (weather)
Special features
GCS (ground clutter suppression, push on/push off)
SLV (slave)
STB (stabilization enable/disable)
HLD display hold (freeze)
SEC (sector scan)
Auto (automatic tilt control)
In-flight stabilization alignment (installation option)
Gain control
Cal (calibrated - normal gain)
Three steps of increased gain (6 dB/step)
Three steps of decreased gain (6 dB/step)
Tilt control
-15° to +15°
(-5° to +5° in 0.25° increments)
(-5° to -15° in 0.50° increments)
(-5° to -15° in 0.50° increments)
Selectable ranges
5, 10, 25, 50, 100, 200, and 300 nmi
Table 1-3. Related Publications.
PUBLICATION
COLLINS PART NUMBER
RTA-84X/85X Receiver/Transmitter/Antenna Repair Manual
523-0774785
WXP-840A/840B/850A/850B Weather Radar Panel Repair Manual
523-0774662
Collins Installation Practices Manual
523-0775254
22 August 1990
1-7/(1-8 blank)
ADDENDUM 4
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet facing page 2-1
of the Installation Section (523-0775824-001118)
This addendum adds the WXA-850A Weather Radar Adapter option to the WXR-840 radar system.
Add the following paragraph in Section 2.1.1 WXR-840 Advanced Weather Radar System Definition immediately
following the last paragraph.
An optional use of the WXR-840 system consists of the RTA-84X Receiver/Transmitter/Antenna and the WXA850A Weather Radar Adapter, with RTA control being provided through a Control Display Unit (CDU). Refer to the
WXA-850A CMM (CPN 523-0776543) for more details on this option.
Addendum 4
30 May 1998
523-0775822-04111A
Sheet 1 of 9
(Facing Page 2-1)
II
section
installation
2.1 GENERAL
MFD:
MultiFunction Display. This refers
to the EFIS display, which normally is situated in the center portion
of the instrument panel for good
visibility by both the pilot and
copilot.
ND:
Navigation Display. This refers to
that part of the EFIS which takes
the place of the conventional HSI
(Horizontal Situation Indicator).
Display:
The general term "display" is used
in the following paragraphs when
referring to an MFD (MultiFunction Display) or an ND (Navigation
Display). Specific references to
either the MFD or ND are made
where applicable.
MODE:
This refers to the specific operating
state of the system. The states
are: OFF, STBY, TEST, TGT, MAP,
and WX.
STBY:
This refers to STandBY, one of the
modes of the system. ln STBY
mode, power is applied to the RTA84X but transmission is inhibited
and the antenna is positioned to
boresight (0° azimuth and 0° tilt).
Also, the normal range mark is displayed along with the STBY annunciation and the display of weather is inhibited.
TEST:
This refers to the self-TEST mode
of the system. In this mode, TEST
is annunciated and a simulated
target return is used to create a
rainbowlike pattern of colors on
the display. This verifies the system’s ability to display weather
target information.
This section contains information necessary for
proper installation of the WXR-840 Advanced
Weather Radar System. The title page at the
front of this section provides an index of the
section.
2.1.1 WXR-840 Advanced Weather Radar
Definition
The WXR-840 Advanced Weather Radar System
consists of one RTA-84X Receiver/Transmitter/
Antenna unit and one or two WXP-840A or WXP840B units. Table 2-1 gives a listing of the
various models of each unit available and the
distinuishing features of each. Throughout this
section, the nomenclature RTA-84X should be
understood as referring to any of the three RTA
units (RTA-842, RTA-844, or RTA-848) listed in
Table 2-1. In addition, the nomenclature WXP840A/B or WXP-840( ) should be understood as
referring to any one of the weather radar panels
listed in Table 2-1.
2.1.2 EFIS System Compatibility
The WXR-840 Advanced Weather Radar System
is compatible with the latest design in Collins
Electronic Flight Instrument Systems (EFIS).
Table 2-2 lists the Collins EFIS which are totally
compatible with the WXR-840 system.
For
details on the compatibility of other EFIS, contact your local Collins General Aviation Division
representative or refer to the current Collins
Price Book.
2.1.3 Glossary
This paragraph provides a glossary of terms and
definitions common to the WXR-840 system.
EFIS:
28 April 1991
Electronic Flight Instrument System. This refers to the generation
of cockpit instruments utilizing crt
displays.
2-1
ADDENDUM 4
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet facing page 2-2
of the Installation Section (523-0775824-001118)
Add following note to Table 2-1 WXR-840 Equipment Covered. (Addition in bold)
Information on the WXA-850A can be found in the WXA-850A CMM (523-0776543).
Addendum 4
30 May 1998
523-0775822-04111A
Sheet 2 of 9
(Facing Page 2-2)
installation 523-0775824
Table 2-1. WXR-840 Equipment Covered.
TGT:
28 April 1991
This refers to the TarGeT alert
feature of the system. When TGT
is selected, the system continues to
transmit and process target information but the display of weather
or ground return information is
inhibited. In this mode, TGT is
annunciated on the display. If a
radar alert target (a radar target
of sufficient intensity to cause a
red level display) is detected within a range of 7 to 200 nmi and 15°
to the left or right of straight
ahead, the TGT flashes to alert the
crew to the possibility of severe
weather conditions ahead.
2-2
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
WXR-840 Advanced Weather Radar System
INSTALLATION MANUAL (523-0775822, 1ST EDITION, DATED APR 28/91)
TEMPORARY REVISION NO. 08
Insert facing page 2-2.
This temporary revision supersedes sheet 2 of Addendum 4.
Subject: Add equipment and note
Add RTA equipment to Table 2-1, WXR-840 Equipment Covered. A note is also added to the table.
Changes are in bold text.
P/O Table 1-1. WXR-840 Equipment Covered
EQUIPMENT
RTA-842
RTA-844
RTA-848
14-INCH
ANTENNA
FLAT PLATE
18-INCH
ANTENNA
FLAT PLATE
LOW SPEED
ARINC 429 (50
kBD) DIGITAL
STABILIZATION
HIGH SPEED
ARINC 429 (100
kBD) DIGITAL
STABILIZATION
AUTOTILT
AND
TARGET
ALERT
ENABLED
COLLINS
PART
NUMBER
12-INCH
ANTENNA
FLAT PLATE
622-9301-001
X
X
622-9301-002
X
X
X
622-9301-003
X
X
X
X
622-9301-004
X
X
X
X
622-9301-011
X
X
X
622-9302-001
X
X
622-9302-002
X
X
X
622-9302-003
X
X
X
X
622-9302-004
X
X
X
X
622-9302-011
X
X
X
622-9303-001
X
X
622-9303-002
X
X
X
622-9303-003
X
X
X
X
622-9303-004
X
X
X
X
622-9303-011
X
X
X
NOTE: Information on the WXA-850A can be found in the WXA-850A CMM (523-0776543).
Temporary Revision 8
523-0775822-08111A
Page 3
Feb 2/01
installation 523-0775824
Table 2-2. WXR-840 and EFIS Compatibility Table.
EFIS SYSTEM
DPU/MPU
EFIS COLLINS
PART NUMBER
WXP-840A/B COMPATIBLE
COLLINS PART NUMBER
EFIS-85A(1)
DPU-85A (with SB 41)
MPU-85A (with SB 41)
622-7244-002
622-7250-002
All CPN’s
EFIS-86A(1)
DPU-86A (with SB 41)
MPU-86A (with SB 41)
622-7247-002
622-7253-002
All CPN’s
EFIS-85B(2/12)
DPU-85G (with SB 25)
MPU-85G (with SB 25)
622-7448-002
622-7454-002
All CPN’s
EFIS-86B(2/12)
DPU-86G (with SB 25)
MPU-86G (with SB 25)
622-7710-002
622-7715-002
All CPN’s
EFIS-85B(4/14)
DPU-85N/MPU-86N
All CPN’s
All CPN’s
EFIS-86B(4/14)
DPU-86N/MPU-86N
All CPN’s
All CPN’s
EFIS-85C(4/14)
DPU-85R/MPU-85R
All CPN’s
All CPN’s
EFIS-86C(4/14)
DPU-86R/MPU-86R
All CPN’s
All CPN’s
EFIS-86D(2)
DPU-86K (with SB 43)
MPU-86K (with SB 43)
622-7713-003
622-7718-003
All CPN’s
EFIS-85E(4/14)
DPU-85S
622-9283-001
622-9283-002
622-9283-003
622-9284-001
622-9284-002
622-9284-003
All CPN’s
All CPN’s
622-9304-01X, 622-9305-01X
All CPN’s
All CPN’s
622-9304-01X, 622-9305-01X
622-9285-001
622-9285-002
622-9285-003
622-9286-001
622-9286-002
622-9286-003
All CPN’s
All CPN’s
622-9304-01X, 622-9305-01X
All CPN’s
All CPN’s
622-9304-01X, 622-9305-01X
MPU-85S
EFIS-86E(4/14)
DPU-86S
MPU-86S
PAC:
This refers to the Path Attenuation
Compensation feature of the system. The purpose of PAC is to
compensate for the radar beam
absorption as it penetrates a given
precipitation cell. This overcomes
the tendency in noncompensated
radar to underdisplay a precipitation cell simply because the energy
is absorbed as it penetrates the
cell.
PAC Alert:
When radar targets are of sufficient magnitude (intensity and
depth) to exhaust the full range of
attenuation correction, a condition
known as PAC Alert exists. PAC
Alert highlights those sectors of
28 April 1991
uncertainty which are masked by
intervening beam absorption. The
bearing toward these areas is
shown by a yellow bar (arc) at the
perimeter of the radar display. The
yellow PAC Alert bar will appear
when the system can no longer
detect a Z4 (red level) target at a
range where Z3 (yellow level) targets would normally be detectable
without intervening weather. The
pilot can then recognize that, from
his present position, any precipitation in the sector between the
displayed weather and the yellow
PAC Alert bar may be underdisplayed and should be avoided.
2-3
installation 523-0775824
arc, and ground targets are display
ed. This mode is typically used for
detection and display of prominent
and familiar ground features as an
aid to navigation. PAC and GCS
features are automatically disabled
in MAP mode. It is for this reason
that MAP should not be used as a
weather detection mode.
Note
The PAC feature is intended for
weather detection modes only.
Using a weather detection mode
and downward antenna tilt to produce a ground map will probably
produce an inaccurate display.
The PAC circuit will incorrectly
detect the return signals from
ground targets as intense storm
targets and try to compensate for
the attenuated signal, resulting in
the yellow PAC Alert band appearing at the perimeter of the display.
In MAP mode, the PAC and PAC
Alert features are automatically
disabled.
STC:
This refers to the Sensitivity Time
Control feature. This feature is
needed to compensate for the dramatic increase in return signal
strength that occurs when a given
storm cell becomes beam-filling.
At that point, the energy reflected
increases so abruptly that without
STC a given cell would be displayed at one or more levels of
intensity higher when at greater
distances (when not beam-filling).
In the WXR-840 system, STC uses
a complex software algorithm that
is different for each display color.
The objective is to display a given
rainfall rate at the same color
throughout the entire operating
range.
Beam Width: Antenna beam width is normally
expressed as the angle between the
3-dB points of the radiation pattern. This is approximately 6° for
the 18-inch antenna, 7.3° for the
14-inch antenna, and 8° for the 12inch antenna.
MAP:
28 April 1991
This refers to the ground MAP
mode of the system. It is annunciated by the word MAP on the display. In MAP mode, the characteristics of the system are optimized
for ground mapping. In addition,
the ½ range annunciator, range
WX:
This refers to the normal weather
(WX) detection mode of the system.
It is annunciated by WX on the
display.
The range arc is
displayed and weather targets are
shown in green, yellow, red, and
magenta. The PAC and STC features are automatically enabled in
WX mode.
GCS:
This refers to Ground Clutter Suppression. When this feature is
selected, those radar returns that
appear as ground clutter are suppressed. This feature eases the
ability to discern rainfall when
viewed in the presence of ground
returns.
SLV:
This refers to the SLaVe feature.
This feature has application only
in dual WXP-840A/B installations.
In SLV, on-side display is determined by the cross-side WXP840A/B control.
STB:
This refers to STaBilization and
specifically to the use of an attitude reference signal to maintain a
constant antenna scan attitude,
unaffected by aircraft pitch and
roll movement. When STB is deselected on the WXP-840A/B, the
attitude reference input signals are
effectively disconnected from the
antenna and USTB (UnSTaBilized)
is annunciated. This has application in those situations where an
attitude reference failure has occurred that would otherwise render
the radar system unusable.
2-4
installation 523-0775824
HLD:
This refers to the HoLD feature,
sometimes called freeze. This feature is selected and deselected by
depressing the HLD button on the
WXP-840A/B. In HLD, the normal
display update is disabled so that
a given display situation can be
studied more closely, undisturbed
by any subsequent display update.
HLD automatically cancels with
any change of MODE, RANGE,
GAIN, GCS, and SLV.
TILT:
This refers to the feature which
allows the pilot or copilot to set the
antenna beam relative to the horizon, in ¼ degree steps. Tilt setting
is important for optimum weather
detection and interpretation.
AUTO:
This refers to the AUTOtilt feature. When this feature is selected, the system automatically adjusts antenna tilt to maintain the
ratio of tilt/range that was established just before AUTO was selected. This reduces the amount of
tilt readjust that may be needed in
order to maintain the same ground
return threshold when a new range
is selected or when the aircraft
changes altitude.
RANGE:
This refers to the selected maximum range to be displayed. Typically, the ND has one range arc
and one range annunciation at the
½ range position. The MFD has
two range arcs and corresponding
range annunciation, one at mid
range and another at max range.
The max range annunciation may
not appear on some earlier MFDs.
On others the max range ring is
replaced by the compass arc. More
recent MFDs display the max
range ring.
SEC:
This refers to the SECtor scan feature. This feature is selected and
deselected by pressing the SEC
switch, which is concentric with
the RANGE switch. When this
feature is selected, the left and
28 April 1991
right scan swing is reduced from
the normal ±60° from straight
ahead to ±30°. This provides the
benefit of an increased display update rate where the dynamics of
the radar target require a more
rapid radar observation.
GAIN:
This refers to the GAIN control
feature of the system. This allows
the adjustment of the system sensitivity to varying target return
intensities. For example, adjusting
the GAIN control ccw from the
CAL position progressively eliminates the weaker targets from the
display, allowing a more definitive
study of the most intense weather
radar targets. These selections are
annunciated by G-1, G-2, and G-3
on the display.
Adjusting the
GAIN control cw has the effect of
increasing the system sensitivity.
These selections are annunciated
by G+1, G+2, and G+3 on the display. In all cases, the selection of
any GAIN switch position other
than CAL (CALibrated) results in
an uncalibrated system where a
given display color is not indicative
of the same rainfall rate as when
in the CAL position.
CAL:
This refers to the CALibrated position of the GAIN control switch.
CAL is the only position in which
the system display colors accurately present the detected rainfall
rate (Z level) for all range selections. It is anticipated that the
WXR-840 system is operated most
of the time with the GAIN control
in the CAL position and that the
other GAIN positions are used only
occasionally. To avoid misinterpretation, the system should never be
left operating unattended with the
GAIN switch in a position other
than CAL, especially in flight.
2-5
ADDENDUM 4
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet facing page 2-6
of the Installation Section (523-0775824-001118)
Change the first sentence to the first paragraph of Segment 2.3.1 General to read as follows:
This paragraph contains installation instructions and other data necessary for the proper installation of the WXR840 Advanced Weather Radar System, including the use of the optional WXA-850A Weather Radar Adapter.
Add the following information to Table 2-3 Contents of Installation Paragraph.
Table 2-3. Contents of Installation Paragraph.
SUBPARAGRAPH
NUMBER
2.3.7
Addendum 4
30 May 1998
523-0775822-04111A
SUBPARAGRAPH TITLE
RTA-84X and WXA-850A Option Installation
APPLICABLE DIAGRAMS
Figure 2-16, Figure 2-17, Figure 2-18
Sheet 3 of 9
(Facing Page 2-6)
ADDENDUM 2
TO
INSTALLATION SECTION (523-0775824)
Located in the
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
523-0775822-00111A, 1st Edition, dated 28 April 1991
Insert this addendum facing page 2-6
At the next revision to this manual, a new paragraph will be added as follows:
2.2.1 Criteria for Antenna Flat Plate Inspection
The following inspection criteria applies to all Collins radar antenna flat plates:
Before the flat plate is installed on the drive mechanism as well as at any service operation, the flat plate
should be inspected for physical damage.
Any dent that deforms the narrow (septum) sidewalls or the main feed manifold on the rear of the flat plate
should be seen as cause for rejection or replacement. The septum should be understood as referring to
the spacers between the front and back surfaces of the flat plate.
A surface dent with an area less than 2-in2 and a depth of not more than 0.050 inch should be seen as
acceptable. A greater surface area or deeper dent should be seen as unacceptable.
Any dent or bending that occurs at the extreme edge of the antenna and outside the last waveguide wall,
can be ignored unless the weld is broken. Any broken weld that results in a separation between the
waveguide wall and the flat plate surface should be seen as unacceptable.
Any warping that results in a flat plate distortion of 0.0625 inch or more, with respect to the center of the
flat plate, should be seen as cause of flat plate rejection and replacement. In the case of convex distortion,
this can be detected by laying the flat plate on a flat bench surface, face down, with the center area of the
flat plate firmly in contact with the bench surface. If any point on the edge of the flat plate is off the surface
by 0.0625 inch or more, the warping should be judged unacceptable. For concave distortion, use a straight
edge ruler of sufficient length against the front surface of the flat plate and note that all points are within
0.0625 inch of the straight edge surface. Use several points in both the vertical and horizontal plane to
ensure that the plate is not twisted.
Note:
If and when windshear detection becomes operational and if these antennae are used in such an
application, the above criteria may not apply. In this case, damage inspection criteria may be
redefined.
Addendum 2
12 May 1995
523-0775824-021118
Sheet 2 of 4
(Facing page 2-6)
installation 523-0775824
2.2 UNPACKING AND INSPECTION OF
EQUIPMENT
Carefully unpack the equipment from the shipping container and visually inspect it for shipping damage. Check the shipping container
against the invoice for proper content; account for
each item on the invoice. Be sure to inspect all
packing material so as not to inadvertently
discard any necessary parts or attaching materials. All claims for shipping damage should be
filed with the transportation company involved.
Replace the packing materials in the original
shipping container and save it for use if claims
for damage are to be filed or, if no defects are
detected, for future use, such as storage or reshipment.
A mockup or detailed drawing of the planned
installation, prepared in advance, frequently aids
in improving the installation by optimizing cable
lengths and determining the amount and type of
hardware needed.
2.3.2 Preparation, Installation, and
Replacement of Mating Connectors
The installation and removal of mating connectors requires special tools, such as the crimping
and extraction tools listed in Table 2-4. In using
these tools for the assembly and repair of connectors, follow the procedure described below and
refer to Figure 2-2 and Figure 2-3.
Observe the following instructions while installing the wires into the connector assemblies:
2.3 INSTALLATION INSTRUCTIONS
2.3.1 General
This paragraph contains installation instructions
and other data necessary for the proper installation of the WXR-840 Advanced Weather Radar
System. Table 2-3 gives an outline of the paragraph, along with a listing of the tables and
figures applicable to each subparagraph.
The installation procedures must be performed as
prescribed to ensure proper operation and
performance of the system. Deviation from these
instructions can result in reduced performance or
damage to the equipment.
a. Be sure to thread all wires through the connector hood assembly first, so the hood can be
installed on the back of the connector after all
wires have been connected.
b. The connecting wire must be crimped into the
contact so the crimped portion of the contact
can enter the connector shell and provide a
positive lock.
c. Use the crimping tool (CPN 372-8108-010) to
crimp each wire into a contact. Use the
insertion tool (CPN 371-8445-010) to insert
the contact into the proper hole in the connector shell, and press in until the lock clicks
into place.
Table 2-3. Contents of Installation Paragraph.
SUBPARAGRAPH
NUMBER
SUBPARAGRAPH TITLE
APPLICABLE DIAGRAMS
2.3
INSTALLATION INSTRUCTIONS
2.3.2
Preparation, Installation, and Replacement of Mating
Connectors
Table 2-4, Table 2-5, and Table 2-6
Figure 2-2 and Figure 2-3
2.3.3
Cabling and Wiring Harness Installation
Figure 2-2 thru Figure 2-6
2.3.4
RTA-84X Receiver/Transmitter/Antenna Installation
and Alignment
Table 2-4 thru Table 2-10
Figure 2-1 thru Figure 2-5 and Figure 2-7
thru Figure 2-11
2.3.5
WXP-840( ) Weather Radar Panel Installation
Table 2-4, Table 2-5, Table 2-6, and
Table 2-11
Figure 2-2, Figure 2-3, Figure 2-4,
Figure 2-6, Figure 2-12, and Figure 2-13
2.3.6
Aircraft Radome Considerations
28 April 1991
2-6
installation 523-0775824
Table 2-4. Special Installation Tools and Hardware.
DESCRIPTION
MANUFACTURER AND
TYPE NUMBER
COLLINS
PART NUMBER
Installation kits
Refer to Table 2-5, Table 2-6, and
Table 2-7.
Crimping tool
Cannon, CCT-D*C-1
372-8102-010
Insertion/extraction tool
Cannon, CIET-20HDB
371-8445-010
Alignment bar
Refer to Figure 2-10.
687-9729-001
RTA-84X mounting screws (qty 4)
1/4-inch-diameter shaft, length as required
Refer to Table 2-8.
For RTA-84X mounting
3/16 inch or as required
Not available from Collins
General Aviation Division
For WXP-840A locking screws
3/32 inch
Hexhead wrench
Electronic inclinometer (for antenna alignment)
Schaevitz Sensing Systems, Inc.
21640 North 14th Avenue
Phoenix, AZ 85027-2839
AngleStar Digital Protractor
d. After inserting each contact, pull gently on
the wire to be sure that it is securely locked.
Each wire should be capable of withstanding
a straight-out pull of about 1.4 kg (3 lb).
e. If it is necessary to remove a contact, use the
insertion/extraction tool to unlock the contact.
Then pull the contact out of the connector
from the rear (wire side). If the wire has
come loose from the contact because of crimp
failure, use the tool to unlock the contact.
Then, using a small stiff pin or piece of wire,
push out the contact by inserting the pin or
wire into the pin socket and pushing the
contact out the rear of the shell.
f. Slide the hood assembly (Figure 2-3) forward
onto the connector shell and secure with
screws as shown. Install the lock assembly.
g. Install the keying plug on WXP-840( ) connector pin J2-5.
2.3.3 Cable and Wiring Harness Installation
Figure 2-4 is the interconnect wiring diagram for
the WXR-840 system; Figure 2-5 and Figure 2-6
show the pin functions and numbering schemes
for the mating connectors. Figure 2-15 gives
detailed circuit information for the WXR-840
system input/output circuits.
It also shows
similar data for the stabilization sources. Refer
to the applicable EFIS system installation manu28 April 1991
Not available from Collins
General Aviation Division
al for similar data for the EFIS system components.
A number of strapping options are provided in
the WXR-840 system. These are shown on the
interconnect diagram and described in Table 2-9
and Table 2-11.
During the preparation and installation of the
interconnecting cabling/harness, observe the
following precautions and instructions:
a. Be sure that all parts of the aircraft electrical
system, such as generators and ignition systems, are properly bonded and shielded to
reduce the likelihood of interference.
b. Be sure to observe the wire length requirements between the RTA-84X and the WXP840( ) units in a dual WXP-840( ) installation.
Refer to Figure 2-4. The high data rate between these units causes the interconnect
cables to acquire the characteristics of an RF
transmission line. Therefore, equal or near
equal cable lengths can result in signal cancellation due to standing-wave interference.
c. Keep the harness away from high-current or
high-energy cables.
d. Leave slack in the cables to allow for normal
flexing due to vibration and installation/
removal.
2-7
ADDENDUM 4
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet facing page 2-8
of the Installation Section (523-0775824-001118)
Change Table 2-5 Contents of Crimp Type Mating Connector Kits as follows:
Change Table Header as shown below: (Change in bold)
Table 2-5. Contents of Crimp Type Mating Connector Kits.
ITEM
QUANTITY IN CONNECTOR KIT
COLLINS
PART NUMBER
687-9726003
002 (alternate)
687-9727002 (alternate)
003**
Add note to bottom row of Table 2-5: (Addition in bold)
* Use insertion/extraction tool CPN 371-8445-010 and crimping tool CPN 359-8102-010 with positioner CPN 359-8102-020.
**Use with WXA-850A Weather Radar Adapter.
Addendum 4
30 May 1998
523-0775822-04111A
Sheet 4 of 9
(Facing Page 2-8)
installation 523-0775824
e. Provide adequate protective wrapping and
clamping at locations where rubbing can
occur.
f. Shields on all shielded wires must be connected as shown on the interconnect diagram.
g. After installation of the harness and before
installation of the equipment, check by actual
application of power, if possible, that the
aircraft power is applied only to the pins
specified and does not appear on others,
especially signal lines.
h. All interconnect wires should be marked in
accordance with the Aircraft Electronics Association’s Wire Marking Standard (refer to
Figure 2-14).
Table 2-5. Contents of Crimp Type Connector Kits.
CRIMP TYPE CONNECTOR KITS
QUANTITY IN CONNECTOR KIT
687-9726ITEM
COLLINS
PART NUMBER
003
687-9727-
002 (alternate)
003
002 (alternate)
Mating connector
RTA-84X (P1)
Shell assembly
Shell assembly
Lock assembly
Hood
or
Hood (not supplied)
*Contacts, socket
*Contacts, socket
371-0213-040
371-0922-040
371-0040-010
371-0186-000
371-0147-000
371-0213-110
371-0946-040
1
1
1
1
1
1
37
37
WXP-840( ) (P1)
Shell assembly
Shell assembly
Lock assembly
Hood
or
Hood (not supplied)
*Contacts, socket
*Contacts, socket
371-0213-030
371-0922-030
371-0040-010
371-0185-000
371-0146-000
371-0213-110
371-0946-040
1
1
1
1
1
1
25
25
WXP-840( ) (P2)
Shell assembly
Shell assembly
Lock assembly
Hood
or
Hood (not supplied)
Key kit
*Contacts, socket
*Contacts, socket
371-0213-040
371-0922-040
371-0040-010
371-0186-000
371-0147-000
629-8381-001
371-0213-110
371-0946-040
1
1
1
1
37
1
1
1
1
37
*Use insertion/extraction tool CPN 371-8445-010 and crimping tool CPN 359-8102-010 with positioner CPN 359-8102-020.
28 April 1991
2-8
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
WXR-840 Advanced Weather Radar System
INSTALLATION MANUAL (523-0775822, 1ST EDITION, DATED APR 28/91)
TEMPORARY REVISION NO. 08
Insert facing page 2-9.
Subject: Revise table header
Revise column header in Table 2-7 as shown below. Change is in bold text.
P/O Table 2-7. Contents of Installation Kit.
ITEM
Temporary Revision 8
523-0775822-08111A
COLLINS PART NUMBER
QUANTITY IN KIT
CPN 687-9728-002
Page 4
Feb 2/01
installation 523-0775824
Table 2-6. Solder Type Connectors.
ITEM
CONNECTOR
COLLINS PART NUMBER
QUANTITY REQUIRED/
INSTALLATION
P1
371-0222-000
371-0186-000
1
1
371-0147-000
371-0040-010
1
1
371-0221-000
371-0185-000
1
1
371-0146-000
371-0040-010
1
1
371-0222-000
371-0186-000
1
1
371-0147-000
371-0040-010
629-8381-001
1
1
1
Mating connectors
RTA-84X
Connector assembly
Hood assembly
or
Hood assembly
Lock assembly
WXP-840( )
Connector assembly
Hood assembly
or
Hood assembly
Lock assembly
P1
Connector assembly
Hood assembly
or
Hood assembly
Lock assembly
Key kit
P2
Table 2-7. Contents of Installation Kit.
ITEM
COLLINS PART NUMBER
QUANTITY IN KIT
CPN 687-9728-001
310-0740-600
310-0288-000
4
4
687-9725-001
687-9725-002
687-9725-003
687-9725-004
1
1
1
1
687-9715-001, -002
687-9715-003, -004
687-9715-005, -006
687-9715-007, -008
687-9715-009, -010
687-9715-011, -012
687-9715-013, -014
2
2
2
2
2
2
2
523-0775-545
2
Mounting hardware
RTA-84X
Flat washers
Lockwashers
Alignment shims
Roll attitude
0.25°
0.50°
0.75°
1.00°
Pitch attitude
0.25°
0.50°
0.75°
1.00°
2.00°
4.00°
8.00°
Installation tag
Mounting screws, hexagon socket head, not supplied in kit; refer to table 2-8 and select length required; quantity 4
required for each RTA-84X.
28 April 1991
2-9
installation 523-0775824
Table 2-8. Mounting Screws.
COLLINS PART NUMBER
†SUPPLIER PART NUMBER
THICKNESS-THREAD, LENGTH
324-2634-000
324-2635-000
324-2636-000
324-2637-000
324-2638-000
324-2639-000
324-2640-000
324-2641-000
324-2642-000
324-2643-000
324-2644-000
324-2645-000
324-2646-000
324-2647-000
MS16997-57
MS16997-58
MS16997-59
MS16997-60
MS16997-61
MS16997-62
MS16997-63
MS16997-64
MS16997-65
MS16997-66
MS16997-67
MS16997-68
MS16997-69
MS16997-70
1/4-20UNC, 3/8 in
1/4-20UNC, 1/2 in
1/4-20UNC, 5/8 in
1/4-20UNC, 3/4 in
1/4-20UNC, 7/8 in
1/4-20UNC, 1 in
1/4-20UNC, 1/4 in
1/4-20UNC, 11/2 in
1/4-20UNC, 13/4 in
1/4-20UNC, 2 in
1/4-20UNC, 21/4 in
1/4-20UNC, 21/2 in
1/4-20UNC, 23/4 in
1/4-20UNC, 3 in
†Available from The Bristol Co., Waterbury, Connecticut.
Table 2-9. RTA-84X Strapping Options.
SELECTION
STRAP FUNCTION
CONNECTOR PINS
STRAPPED
UNSTRAPPED
Digital/Analog Attitude
P1-30 to P1-12
Analog
Digital
With digital attitude selected
P1-31 to P1-12
†ARINC 429, 100 kBd
ARINC 429, 50 kBd
With analog attitude selected
P1-31 to P1-12
50 mV/°
200 mV/°
*400-Hz attitude ref: 26 or 115 V ac
P1-32 to P1-12
26 V ac
115 V ac
Instant GCS
P1-34 to P1-12
Enabled
Disabled
Antenna flat plate size12-inch
P1-28 strapped to P1-12, P1-29 open
14-inch
P1-28 open, P1-29 open
18-inch
P1-28 open, P1-29 strapped to P1-12
*Attitude reference is not required when digital data is used.
†ARINC 429, 100 kBd available only in -002 units.
2.3.4 RTA-84X Receiver/Transmitter/
Antenna Installation and Alignment
2.3.4.1 Introduction
There are two primary requirements in radar
antenna installation:
a. The RTA-84X mounting surface must be as
perpendicular as possible to the aircraft pitch
attitude (roll axis). Some correction can be
accomplished by means of shims and spacers.
28 April 1991
Refer to Figure 2-1 and Figure 2-7 through
Figure 2-11.
b. The aircraft radome must allow a minimum
transmissivity of 85 percent. Refer to paragraph 2.3.6 for additional discussion regarding the aircraft radome.
2.3.4.2 Strapping Options
Refer to Table 2-9 for the RTA-84X strapping
options.
2-10
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
WXR-840 Advanced Weather Radar System
INSTALLATION MANUAL (523-0775822, 1ST EDITION, DATED APR 28/91)
TEMPORARY REVISION NO. 08
Insert facing page 2-10.
Subject: Revise note in Table 2-9. Change is in bold text.
Table 2-9. RTA-84X Strapping Options.
STRAP FUNCTION
CONNECTOR PINS
SELECTION
STRAPPED
UNSTRAPPED
Digital/Analog Attitude
P1-30 to P1-12
Analog
Digital
With digital attitude selected
P1-31 to P1-12
†ARINC 429, 100 kBd
ARINC 429, 50 kBd
With analog attitude selected
P1-31 to P1-12
50 mV/°
200 mV/°
*400-Hz attitude ref: 26 or 115 V ac
P1-32 to P1-12
26 V ac
115 V ac
Instant GCS
P1-34 to P1-12
Enabled
Disabled
Antenna flat plate size 12-inch
P1-28 strapped to P1-12, P1-29 open
14-inch
P1-28 open, P1-29 open
18-inch
P1-28 open, P1-29 strapped to P1-12
*Attitude reference is not required when digital data is used.
†ARINC 429, 100 kBd available only in –002, -003, -004 units.
Temporary Revision 8
523-0775822-08111A
Page 5
Feb 2/01
installation 523-0775824
2.3.4.3 Installation
center location, locate and drill one of the
upper mounting holes, either left or right.
Refer to Figure 2-1 and Figure 2-7 through
Figure 2-11.
Note
a. Park the aircraft in a reasonably level attitude.
Tap holes in bulkhead or use fixed position fasteners to secure the RTA-84X to
the aircraft bulkhead. The use of floating
fasteners will cause errors in antenna
alignment.
Note
It is not required that the aircraft be leveled. The objective is to have the aircraft
well within the limits of the inclinometer,
which is a gravity device and accurate up
to 19.99° from horizontal. All four edge
surfaces of the inclinometer are calibrated
so that measurements can be made with
the display window in its most horizontal
position.
b. Measure the aircraft roll attitude using the
electronic inclinometer referenced in table
2-4. Record the value measured.
c. Measure the aircraft pitch attitude using the
electronic inclinometer, and record the value.
d. If mounting holes are satisfactorily predrilled,
skip to step m below. Otherwise, select the
center location for the RTA-84X mounting
hole pattern.
Refer to Figure 2-7 or
Figure 2-9 for hole pattern dimensions. Be
sure to consider the contour of the radome in
selecting the antenna location.
Note
The antenna scans to a maximum of 62° left
and right and tilts to a maximum of 32° up
and down. Within those limits the cone of
radar beam illumination must be clear of any
material or fixtures that can be non-transparent to the RF energy or in any way distort
the beam. This includes such things as recognition lights. Further, the shape of the radome, as well as any other items in the vicinity of the antenna, must not mechanically
interfere with the free movement of the
antenna. If the bulkhead (or mounting surface) is not perpendicular to the aircraft pitch
attitude, some type of adapter is needed to
provide a perpendicular mounting surface.
e. Refer to figure Figure 2-7 or Figure 2-9 for
dimensions. Measuring from the selected
28 April 1991
f.
As shown in Figure 2-11, use one mounting
screw (not supplied), one flat washer, and one
lockwasher (supplied in mounting hardware
kit), and attach the alignment bar. Use the
socket-head wrench to tighten the screw
enough to support the weight of the bar and
inclinometer, but yet allow the free end to be
manually adjusted up or down.
g. With the electronic inclinometer resting on
the alignment bar, adjust the bar by moving
its free end up or down so the inclinometer
indicates an angle as close as possible to the
aircraft roll attitude measured in step b.
Note
The objective is to locate the second upper
mounting hole so that a center line drawn
through the two upper mounting holes is
within 0.25° of the same attitude as the
aircrafts roll attitude. Shims are provided in the installation kit to correct for
errors up to 1°. However, accuracy in
locating this second hole can eliminate
the need for these shims.
h. Mark the second hole location using a center
punch in the countersunk hole. Remove the
inclinometer and alignment bar and drill this
hole.
i. Install two socket-head mounting screws (not
supplied) with washers and lockwashers from
the installation kit in the two upper mounting holes. Leave about 1/2 inch of space
between the mounting surface and the flat
washer for the RTA-84X mounting pads.
j. Install the RTA-84X onto the two socket-head
mounting screws. Be sure the washers are
between the screw head and the mounting
pad. Tighten the screws enough to hold the
unit securely against the mounting surface.
2-11
installation 523-0775824
k. Swing the flat plate to the left or right to
facilitate access to the lower mounting holes.
Mark the two lower screw locations. Locate
these holes in the center of the mounting slot
of the lower mounting pads to allow equal
adjustment in either direction if needed.
l. Loosen the two upper screws and remove the
RTA-84X. Drill the two lower holes.
m. Install the RTA-84X onto the two upper
screws, and then install the two lower screws
and tighten all four screws to a snug fit.
n. Locate and provide the necessary cable restraints for the interconnecting cable.
o. Connect the electrical mating connector to
connector J1, and engage and lock the lock
assembly.
p. Do not install the aircraft radome until after
the antenna alignment procedure is completed.
2.3.4.4 Mechanical Alignment
2.3.4.4.1 Introduction
In order to properly perform the mechanical
alignment, it is necessary to have the aircraft in
a reasonably level attitude. A precise measurement of the roll and pitch attitude is used as a
reference in making the following adjustments.
The objective of this procedure is:
a. To mechanically align the RTA-84X assembly
so that, when the antenna is at 0° tilt, the
radar beam is parallel within 0.25° of the
aircraft pitch attitude, measured vertically.
See Figure 2-1*.
Note
If alignment shims are used to compensate for a nonvertical mounting surface, it
is important to check that the resulting
forward displacement of the RTA-84X
does not result in interference between
the radome and the antenna flat plate
motion.
b. To mechanically align the RTA-84X so that
the horizontal scan plane is parallel within
0.25° of the aircraft roll attitude. This ensures that roll compensation is symmetrical;
see view C of figure Figure 2-8.
2.3.4.4.2 Procedure
a. Ensure the aircraft is park a reasonably level
attitude.
Note
It is not required that the aircraft be leveled.
The objective is to have the aircraft well
within the limits of the inclinometer, which is
a gravity device and accurate up to 19.99°
from horizontal. All four edge surfaces of the
inclinometer are calibrated so that measurements can be made with the display window
in its most horizontal position.
b. Measure the aircraft roll attitude using the
electronic inclinometer referenced in table
2-4. Record the value measured.
c. Measure the aircraft pitch attitude using the
electronic inclinometer, and record the value.
d. Ensure that the stabilization system is off or
that the roll and pitch inputs to the radar
system are at null.
e. Turn radar power on and select STBY on the
WXP-840( ). The antenna should stop at
boresight (zero pitch and zero scan). Turn
the power off.
f. Remove RTA-84X from the aircraft.
g. Install two socket-head screws in the two
upper mounting holes. Leave about 1/2 inch
of space between the mounting surface and
the socket-head.
h. Place the electronic inclinometer across both
screws. Record the reading on the inclinometer. Subtract the aircraft roll attitude measured in step b from this reading. This is the
rotational error that will be removed by
means of a shim selected from the installation
kit, CPN 687-9728-001.
* A third potential misalignment is suggested in view B of figure 2-8. In this condition, the mounting
surface is horizontally misaligned with respect to the aircraft center line so that the antenna faces
to the left or right of dead ahead. This causes a target to appear on the screen at the wrong azimuth.
At installation, this error is hard to detect. Fortunately, however, the error tends to become
insignificant at close-in ranges.
28 April 1991
2-12
installation 523-0775824
Table 2-10. Pitch Alignment Correction Shim Selection Guide.
ANTENNA PITCH
CORRECTION
NEEDED
UPPER SHIMS FOR ANTENNA PITCH
DOWN OR LOWER SHIMS FOR
ANTENNA PITCH UP
LOWER SHIMS FOR ANTENNA PITCH
DOWN OR UPPER SHIMS FOR
ANTENNA PITCH UP
DEGREE(S)
THICKNESS
(INCH)
COLLINS
PART NUMBER
THICKNESS
(INCH)
COLLINS
PART NUMBER
0.25
0.50
0.75
1.00
2.00
4.00
8.00
0.045
0.089
0.134
0.178
0.356
0.713
1.433
687-9715-001
687-9715-003
687-9715-005
687-9715-007
687-9715-009
687-9715-011
687-9715-013
0.021
0.042
0.063
0.084
0.168
0.336
0.674
687-9715-002
687-9715-004
687-9715-006
687-9715-008
687-9715-010
687-9715-012
687-9715-014
Note
1. The values are approximately linear: therefore, combinations can be selected for correction values not specifically listed.
For example, for a correction of 3.75°, add shim thickness listed for 2.0°, 1.0°, and 0.75°.
2. Two of each shim are supplied in kit CPN 687-9725-001.
i.
If the result is more than 1.25°, the mounting
holes were improperly located. If they can be
relocated, this action should be taken. Otherwise, install the 1-inch shim supplied in the
installation kit. The remaining, excess error
cannot be mechanically removed. The inflight calibration procedures can be used to
remove up to one additional degree of error.
j. If the error is less than 0.13°, no shims are
needed and this alignment procedure is complete for this installation.
k. If the error is more than 0.13° but less than
1.25°, select the shim closest to the angle
measured.
l. Manually tip the inclinometer slightly to
determine the direction of rotation needed to
bring the reading to within 0.25° of the roll
attitude.
m. If ccw rotation is needed, remove the upper
righthand screw and install the selected shim
on it. If cw rotation is needed, remove the
upper left-hand screw and install the selected
shim on it.
n. Reinstall the screw with the selected shim.
Be sure the shim is properly seated within
the mounting hole.
o. Use the electronic inclinometer to ensure that
the flat plate is at 90° ±0.25° with respect to
the aircraft pitch attitude.
28 April 1991
Note
By placing the side of the electronic inclinometer against the flat plate surface,
you can measure the angle directly. Refer
to figure 2-1. Be sure to get the edge of
the inclinometer between the vertical
rows of solder tabs on the flat plate surface and try to make all measurements at
approximately the same place on the flat
plate. The reading should be within 0.25°
of the pitch attitude.
Caution
If shims are necessary for pitch alignment, they must be placed under both the
upper and lower mounting pads as shown
in Figure 2-1. Placing the shims under
the upper pads only, for example, will
result in a gap between the lower pads
and the mounting surface. This gap must
be filled by a shim of complementary
thickness, otherwise the force applied by
the lower mounting screws can break the
pad.
Install shims under the upper and lower
mounting pads to correct for proper alignment. Refer to Table 2-10 and Figure 2-1.
Tighten all four screws.
2-13
installation 523-0775824
Pitch and Roll Attitude Alignment Diagram
Figure 2-1
p. When the alignment procedure is completed
and satisfactory shims have been selected for
installation, bond all selected shims to the
airframe radar antenna mounting surface,
this includes the roll and pitch alignment
shims. Refer to the instructions shown in
Figure 2-1. Be sure to use about the same
amount of adhesive on all shims to minimize
the misaligning effect of the adhesive. Be
sure, also, to use a minimum amount of
bonding material and remove excess to avoid
28 April 1991
bonding the RTA-84X or the mounting screws
to the mounting surface or to the shims.
q. Collins General Aviation Division recommends that a record be made of the type/size
of shims installed on a particular aircraft.
Figure 2-1 shows the tag that is supplied as
part of the shim kit (CPN 687-9728-001).
This tag is to be completed and appropriately
secured near the radar installation. Do not
affix it to the RTA-84X.
2-14
installation 523-0775824
Table 2-11. WXP-840( ) Strapping Options.
SELECTION
CONNECTOR PINS
STRAPPED
UNSTRAPPED
*Dual WXP-840( )
J2-29 to J2-12
Right side
Left side
Enable in-flight stabilization calibration
J2-28 to J2-12
Enabled
Disabled
STRAP FUNCTION
*Leave J2-29 open for single WXP-840( ) installations.
2.3.5 WXP-840( ) Weather Radar Panel
Installation
2.3.5.1 Introduction
Mount the WXP-840A/B(s) in the aircraft instrument panel in a convenient location for easy
access by the operator(s). Refer to Figure 2-12 or
Figure 2-13 for outline and mounting dimensions
and connector information. The WXP-840A is
front panel mounted. The WXP-840B requires
Dzus fasteners.
2.3.5.2 Strapping Options
Table 2-11 describes the strapping options for the
WXP-840( ).
2.3.5.3 Lighting Selection
For 28-V dc lighting, connect the lighting source
to J2-2 and connect a jumper between rear connector pins J2-1 and J2-22.
For 5-V ac/dc lighting, connect the lighting source
to J2-1. (Leave J2-2 open.)
2.3.5.4 Installation
If the WXP-840( ) is to be installed in an IMT-85
mounting tray, refer to the appropriate EFIS
installation manual for installation details.
Otherwise, refer to Figure 2-12 or Figure 2-13 for
the outline and mounting dimensions.
Warning
Be sure to open the circuit breaker before
connecting the equipment to the aircraft
harness. Check for complete connector
mating before applying power.
28 April 1991
Connect the aircraft harness mating connectors
to WXP-840( ) rear connectors Jl and J2 as
required. Insert the unit into its proper location.
Secure the WXP-840A with four integral turnlock
fasteners. Use a 3/32-inch hexkey drive to tighten the fasteners. Secure the WXP-840B by
tightening the Dzus fasteners. Clearance is
required on the rear surfaces of the panel for the
turnlock fasteners.
2.3.6 Aircraft Radome Considerations
The average one-way transmission should not be
less than 90 percent for any continuous scan of
the antenna relative to the radome. The minimum transmissivity at any point should not be
less than 85 percent throughout the window area
of the basic radome, including any installed rain
erosion protection. (The window area is that
portion of the radome which is illuminated by the
antenna as the antenna is tilted and rotated in
azimuth to its mechanical limits.)
The addition of lightning protection devices and
trim finishes should not degrade the transmission
efficiency by more than 3 percent. Average
radome paint causes a loss of about 3.5 to 5
percent in transmissivity. Rubber or Mylar®
boots, where properly installed, present about a
5-percent loss. If a boot is used, it must be
adequately sealed to prevent moisture accumulation between the boot and the radome surface.
Plastic boots usually present a loss of 20 to 50
percent, which makes them totally unacceptable.
If there is reason to question the transmissivity
of the radome, it should be checked by a reputable radome authority, such as Cair Radomes,
Plastics and Synthetics Division of Norton Company, Akron, Ohio.
2-15
ADDENDUM 4
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet facing page 2-16
of the Installation Section (523-0775824-001118)
Add new Paragraph 2.3.7.
2.3.7 RTA-84X and WXA-850A Option Installation
If the WXA-850A option is to be installed, complete all applicable parts of Paragraphs 2.3.1 through 2.3.4.
The WXA-850A then is installed with use of two control adapter mounts (either CPN 827-5060-001
[standard mount] or CPN 628-9865-001 [preferred mount]). Refer to Figure 2-19, Figure 2-20 and Figure 221 for more details.
The WXA-850A typically installed in the equipment bay of the aircraft.
NOTE
One or two WXA-850A units may be installed depending on aircraft specifications.
Electrical interconnects are given in Figure 2-4 WXR-840 Advanced Weather Radar System Interconnect
Wiring Diagram with the exception of two pins.
NOTE
The wiring connections for the WXA-850A are the same as for the WXP-840A/B except
for pins J2-15 and J2-16 (ARINC 429 CONTROL DATA OUTPUT) which are not applicable
to the WXA-850A.
With the WXA-850A installation, the ARINC 429 control words for the RTA come from a secondary source,
usually from a Control Display Unit (CDU).
Refer to the WXA-850A CMM (CPN 523-0776543) for more details.
Addendum 4
30 May 1998
523-0775822-04111A
Sheet 5 of 9
(Facing Page 2-16)
installation 523-0775824
The antenna scans up to a maximum of 62° to the
left and right and 32° tilt up and tilt down (half
for manual tilt adjust and half for stabilization).
Within those limits, the cone of radar beam
illumination must be clear of any material or
fixtures that can be nontransparent to the RF
energy or in any way distort the beam. This
includes such things as recognition lights. Further, the shape of the radome, as well as any
other items in the vicinity of the antenna, must
not interfere with the mechanical movement of
the antenna. Figure 2-7 defines the minimum
space required by the unit, as measured from the
unit mounting base. If shims and/or special
mounting adapters are used which effectively
move the unit forward from the antenna mounting surface, these added dimensions must be
taken into consideration for determining whether
adequate clearance is provided.
than one LRU, the MOST PROBABLE CAUSE
OF FAILURE column lists the line replaceable
units in the order of the greatest likelihood of
failure.
Users should be guided by FAA Advisory Circular
43-14, dated 24 February 1977, Maintenance of
Weather Radomes, in the Collins Installation
Practices Manual (CPN 523-0775254).
2.4.1.2 Radar Antenna Operation
2.4 POSTINSTALLATION TEST
2.4.1.1 EFIS Cross-side Switching
Typically, the MFD and the left side ND are controlled by the pilot’s (left) side controls (DCP-85
or DSP-85). If cross-side control switching is
provided, it is assumed that the operator is
familiar with that system’s operation. No attempt is made in this procedure to guide the
operator in that regard. Further, it is also
assumed that in dual WXP-840A/B installations,
the MFD and left side ND radar displays are
controlled by the pilot’s WXP-840A/B, while the
right side ND radar display is controlled by the
right side WXP-840A/B.
If this is your first exposure to the WXR-840 Advanced Weather Radar System, you will notice
antenna operation somewhat different from other
systems. This paragraph describes that operation.
2.4.1 Introduction
Warning
The area within the scan arc and within
0.65 meter (2 feet) of an operating WXR840 Advanced Weather Radar System can
be a hazardous area. Do not operate the
system in any mode other than standby
(STBY) or test (TEST) when the antenna
might scan over personnel within that
range. FAA Advisory Circular 20-68B
provides additional details on the radiation hazards associated with ground operation of airborne weather radar (refer to
the Collins Installation Practices Manual,
CPN 523-0775254).
Only authorized and qualified personnel should
be allowed to operate the WXR-840 Advanced Weather Radar System. The postinstallation test
procedures are provided in table 2-12. In those
cases where a test failure can be caused by more
28 April 1991
There are three distinct operational features that
you may see:
a. Altitude Determination
At the scan turnaround point for every third
scan sweep, the antenna automatically changes its tilt to two specific downward tilt angles.
In flight, this allows the system to establish
an altitude reference that is used in the AUTO
tilt feature. Therefore, depending on where
the TILT control is set, you will see the antenna tilt up or down at these scan turnaround
points.
b. Automatic Tilt Calibration
This operational feature is dependent on the
TILT control setting.
The automatic tilt
feature requires knowledge of tilt-zero reference. Tilt-zero is established by means of an
optical sensor built into the tilt mechanism.
2-16
installation 523-0775824
As the antenna sweeps, the zero reference
used in the calculating process can become
less precise because of computational error
buildup. Consequently, the program periodically drives the antenna to zero tilt (the optical sensor) and thereby recalibrates the tilt
system. In systems using two WXP-840A/B
controls, however, this will not occur if one
TILT control is set above zero and the other
below zero. In this case, the unit will cross
through zero at each scan sweep and thus no
special calibration action is required. Similarly, in single or dual control systems, with
either or both TILT controls set above zero,
you will not see this zero calibration maneuver
because the system will calibrate as it passes
through zero during the altitude pass as
described in paragraph a.
c. Rectangular Scan Pattern
This scan pattern is seen in systems using two
WXP-840A/B controls and is caused when the
TILT control settings are not identical. In
such a system, the antenna alternates between the two different TILT commands for
each sweep, resulting in the rectangular scan
pattern.
2.4.1.3 Test Procedures
The postinstallation test procedures are provided
in Table 2-12.
Table 2-12. Postinstallation Test Procedures.
TEST
NO.
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Warning
The relatively low power output of the WXR-840 Advanced Weather Radar System makes is reasonably safe to operate
indoors. However, operators should take necessary and reasonable precautions to ensure that personnel and
equipment specially sensitive to microwave radiation are not exposed. Be guided by FAA Advisory Circular 20-68B
(refer to the Collins Installation Practices Manual, CPN 523-0775254).
1.0
Initialization
Make the following selections.
On WXP-840A/B (both sides if dual):
MODE - OFF
GCS - released
STB - released
GAIN - CAL
TILT - center (0)
AUTO - in (off)
HLD - not selected
SEC - not selected
RANGE - 5
Aircraft power - on
On MFD:
PWR - on
MODE - RDR
On DCP-85/DSP-85:
ARC or MAP format
Push RDR button.
Note
The colors of weather radar mode annunciators, arc format, and map format depend on the type of EFIS display being
used. Refer to the appropriate EFIS manual for annunciator, arc format, and map format colors.
28 April 1991
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Table 2-12. Postinstallation Test Procedures.
TEST
NO.
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Note
In dual installations, perform this procedure first from the left side WXP-840A/B. At the start of the procedure,
depress the SLV switch on the right side WXP-840A/B. During the course of the procedure, the right side ND display
should be identical to that of the left side except that the mode annunciation will be preceded by an X (eg, XWX,
XMAP, etc). Therefore, during the course of the procedure, it is wise to glance over to the right side display,
occasionally, to ensure that the displays agree. When this procedure for the left side is completed, it must be repeated
for the right side.
1.0
(Cont)
Stabilization
Off or null
Note
A portion of the test in this table can be performed inside the hanger.
2.0
Standby Test
On WXP-840A/B, left side, set MODE to
STBY.
3.0
On MFD or ND, range annunciator indicates the following:
RTA, WXP
RANGE
FULL
HALF
5
10
25
50
100
200
300
5
10
25
50
100
200
300
2.5
5
12.5
25
50
100
150
Self-Test
On WXP-840A/B, set RANGE to 25 and
MODE to TEST.
5.0
EFIS, WXP, RTA
Range Annunciator
On WXP-840A/B, set RANGE as follows:
4.0
In approximately 20 seconds, one range
arc with (2.5) at right end of range arc,
airplane symbol at bottom center, compass sector, and STBY annunciator appear.
On MFD or ND, antenna scans, test pattern 120°, six color bands outward beyond black around apex: green, yellow,
red, magenta, red/magenta, and yellow
(red/magenta alternates colors each scan
sweep). Refer to Figure 3-2 in the operation section.
RTA, WXP
Set RANGE to 10 or 50 and then back to
25.
Test pattern erases and then begins to
redevelop.
RTA
Before pattern is complete, press HLD
(only once).
Test pattern development stops and annunciator alternates between HOLD and
TEST.
Press HLD.
Test pattern resumes development and
annunciator is constant TEST.
Hold Test
28 April 1991
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Table 2-12. Postinstallation Test Procedures.
TEST
NO.
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Note
If the radome is installed, antenna operation cannot be observed. Unless it can be removed easily, you may skip this
test in favor of the outside-of-hanger tests, where the display is used to determine tilt operation.
6.0
TILT Control Test
On WXP-840A/B, set MODE to TEST and
RANGE to 25.
RTA, WXP
Adjust TILT cw from center.
Antenna tilts up and a positive tilt angle
is displayed on MFD or ND, 15° max.
Adjust TILT ccw from center.
Antenna tilts down and a negative tilt
angle is displayed on MFD or ND, 15°
max.
Set MODE to STBY.
Antenna stops at boresight.
RTA, WXP
Tilt angle is now shown prefixed with an
A (eg, A+10.0, A-2.5, etc).
WXP, RTA
AUTO Tilt Annunciator Test
On WXP-840A/B, pull outward on AUTO
knob and adjust TILT.
Push in AUTO knob.
Note
The following step applies only to installations with dual WXP-840A/B controls.
7.0
SLV Function Test
Up to this point, all annunciations on the
right side should have been in agreement
with those on the left side except that
the mode annunciation was preceded by
an X.
Right Side Test
Release SLV switch on right side WXP840A/B and depress left side SLV switch.
Repeat all tests, starting with test 2.0,
using right side WXP-840A/B.
Double SLV Default Test
Depress SLV switch on both WXP-840A/B
controls.
Note that all displays show that system
is in standby and antenna parks at center scan.
EFIS, WXP, RTA
Set MODE on either WXP-840A/B to
TEST.
Note that all displays show that system
remains in standby.
EFIS, WXP
28 April 1991
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Table 2-12. Postinstallation Test Procedures.
TEST
NO.
8.0
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
STB Control Test
Note
In this step, a stabilization source input is required. There are three possible methods to supply this input:
1. Install the gyro on a tilt table and introduce the necessary input by tilting the gyro.
2. Use the flight-line test fixture shown in Figure 5-3 in the maintenance section, and patch a simulated roll/pitch
signal into the RTA-84X.
3. On an AHS-85( ) equipped installation, actuate the STIM mode to supply one or more of the simulated pitch/roll
input signals.
Note
There should be no need to make an accurate measurement of this function. The objective is to ascertain that the
system responds to a roll and pitch input. However, if a stabilization problem is likely, perform the stabilization
accuracy test below.
8.1
Inside Hanger STB Control Test With Radome Removed
On WXP-840A/B, set MODE to TEST and
TILT to 0 (center).
Antenna scans.
Using one of the methods described in
test 8.0, apply 4° to 8° of pitch-down input.
Antenna pitches up by amount of input.
ON WXP-840A/B, release STB switch
(STB off).
Antenna returns to horizontal scan and
USTB is annunciated.
Set pitch input to zero (null).
There is no change in antenna scan motion.
Press in on STB switch (STB on).
USTB is not displayed.
Apply 4° to 8° of roll right input (right
wing down).
Antenna tilts up when scan is to right of
center and down when scan is to left.
ON WXP-840A/B, release STB switch
(STB off).
Antenna returns to horizontal scan and
USTB is annunciated.
Set pitch input to zero (null).
There is no change in antenna scan motion.
Press in on STB switch (STB on).
USTB is not displayed.
RTA, WXP
RTA, WXP
Note
Unless any additional stabilization testing is necessary (test 9.0), disconnect any equipment or facility used in this
stabilization test and restore the installation to its normal configuration.
Note
This completes the in-hanger procedures for installations with a single WXP-840A/B. If desired, test 9.0 can be
performed to check the stabilization to its normal configuration.
28 April 1991
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Table 2-12. Postinstallation Test Procedures.
TEST
NO.
8.2
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Outside Hanger STB Control Test With
Radome Installed
In the next step, the aircraft must be outside the hanger. You should situate the aircraft so that the radar has a
clear view, extending ideally for several miles, and a reasonable horizontal and of 60° to 120°.
Warning
In the next step, the transmitter is turned on. Be certain that no personnel or combustible materials are within the
±60° hazardous area and a few feet from the front of the aircraft. Be guided by FAA Advisory Circular 20-68B (refer to
the Collins Installation Practices Manual, CPN 523-0775254).
On WXP-840A/B, set MODE to WX and
RANGE to 10 or 25. Be sure GCS is not
selected.
RTA, WXP, stabilization system
Adjust TILT so that ground return is
shown at or near max distance.
9.0
Using one of the methods described in
test 8.0, apply 4° to 8° of pitch down input.
Ground return disappears or moves away
from apex (antenna tilts up).
Release STB switch (STAB off).
Ground return moves back to earlier
position and USTB is annunciated.
Press in on STB switch (STAB on).
Ground return position does not change
and USTB is not displayed.
Apply 4° to 8° of pitch-up input.
Ground return moves closer to apex of
display.
Set pitch input to zero (null).
Ground return moves back to earlier
position.
Apply 4° to 8° of roll right input (right
wing down).
Ground return moves away or disappears
on right side of display and moves closer
on left.
On WXP-840A/B, press in on STB switch
(STAB off).
Ground return moves back to earlier
position and USTB is annunciated.
Set roll input to zero (null) and press STB
switch (STB on).
Ground return remains and USTB is not
displayed.
Stabilization Accuracy Test
Note
This test requires that the radome be removed and therefore should be seen as optional. This test is only required if
there is strong evidence of a stabilization accuracy problem.
Note
This test requires a means of stopping antenna scan at certain scan angles in order to measure the tilt angle resulting
from the stabilization inputs. This is most conveniently done by using the RTA flight-line test fixture shown in
Figure 5-3 in the maintenance section and using the POWER ON/OFF switch to interrupt primary power to the unit.
An alternate method is to interrupt primary power by opening the circuit breaker at the appropriate instant. Antenna
scan can be monitored in the cockpit by observing the sweep on the radar display; antenna scan and display sweep are
synchronized.
28 April 1991
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installation 523-0775824
Table 2-12. Postinstallation Test Procedures.
TEST
NO.
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Note
The objective of this step is to detect relatively large errors in antenna mechanical alignment. The in-flight stabilization alignment procedure can compensate for a maximum of about 1° of roll and 1° of pitch alignment error and for a
gyro gain error of about 25%. Therefore, this step should prove that the antenna is within 1° of perfect alignment.
9.0
(Cont)
On WXP-840A/B, set MODE to TEST.
Apply the following gyro inputs, using one
of the methods described in step 8.0.
9.1
Gyro input:
ROLL
PITCH
(Null)
Up 10°
Note
In analog stabilization systems, it may be wise to measure the gyro input for added assurance that the input is correct.
Use the test jacks on the RTA flight-line test fixture and an accurate RMS meter. 10° of roll or pitch at 50 mV/° should
give a reading of 0.500 V ac, and 10° of roll or pitch at 200 mV/° should give a reading of 2.00 V ac.
Note
Use the electronic inclinometer placed against the face of the antenna (shown in Figure 2-1) or against the flat plate
waveguide mounting flange to make the following measurements.
When antenna is at 0° scan, turn power
off.
9.2
RTA
Measure antenna tilt. It should be tilted
up 10° from aircraft/gyro pitch 0.
RTA
Reapply power and set gyro input to:
ROLL
PITCH
(Null)
Down 10°
When antenna is at 0° scan, turn power
off.
9.3
Measure antenna tilt. It should be tilted
down 10° from aircraft/gyro pitch 0.
Reapply power and set gyro input to:
ROLL
PITCH
Right 10°
(Null)
Note
In the following steps, you are asked to stop the antenna at the right or left scan points. You should avoid stopping the
antenna at those points where it tilts down for the altitude check. Watch the movement for a time and notice when
those down tilts occur (you should see them at the end of every third sweep) and pick one of the other two points. Be
aware that you may pick one of the points where the antenna does its periodic 0° calibration check. If you do, you will
likely measure 0° pitch. One cannot reliably predict where or how frequently these checks will occur.
When antenna is at extreme left scan
point, turn power off.
Measure antenna tilt. It should be tilted
down 8.7 ±0.2° from aircraft/gyro 0.
Reapply power and, when antenna is at
extreme right scan point, turn power off.
Measure antenna tilt. It should be tilted
up 8.7 ±0.2° from aircraft/gyro pitch 0.
28 April 1991
RTA
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Table 2-12. Postinstallation Test Procedures.
TEST
NO.
9.4
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Reapply power and set gyro input to:
ROLL
PITCH
Left 10°
(Null)
Note
In the preceding step and in the next step, an equal and opposite deviation can indicate that the antenna is not aimed
correctly along the longitudinal (roll) axis of the aircraft (view B in Figure 2-8). To correct this condition, shim either
the left or right side of the antenna, using the same shim thickness for both the upper and lower mounting tabs, to
shift the aim of the antenna toward the right or left side respectively. If the error is not equal, it can indicate pitch
misalignment of the antenna (view D of Figure 2-8). This error should have been detected in steps 9.1 and 9.2. Too
much tilt at both scan angles can indicate that the antenna is rotated; that is, the antenna scan plane is not parallel
to the wings of the aircraft. This requires rotation of the antenna to compensate.
When antenna is at extreme left scan
point, turn power off.
Measure antenna tilt. It should be tilted
up 8.7 ±0.2° from aircraft/gyro pitch 0.
Reapply power and, when antenna is at
extreme right scan point, turn power off.
Measure antenna tilt. It should be tilted
down 8.7 ±0.2° from aircraft/gyro pitch 0.
RTA
Note
If any of these tests were significantly out of tolerance and it is clearly not the result of misalignment or a stabilization
system failure, the RTA-84X should be returned for repair.
Remove power from the system and disconnect the RTA flight-line test fixture.
Reapply power to the system and continue below.
10.0
Target Alert Function Test
Set MODE to TGT.
Antenna sweeps and a boxed TGT appears in upper right corner of display.
RTA, WXP
No weather or ground clutter is displayed.
Note
If a radar target such as a fairly intense rain cloud is visible at a distance of at least 7 miles and within 15° of straight
ahead, it may cause the annunciator to flash. If such a radar target is not available in the area, it may not be possible
to make a reasonable test of the target alert function.
11.0
Map Mode Function Test
Set Mode to MAP.
Antenna sweeps and MAP is annunciated.
RTA, WXP
TGT from previous step disappears.
Range mark changes color.
Ground targets appear.
Select different range.
28 April 1991
Ground targets become less pronounced
with grater ranges and tend to disappear
into vertex at ranges of 200 and 300.
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installation 523-0775824
Table 2-12. Postinstallation Test Procedures.
TEST
NO.
11.0
(Cont)
12.0
MANUAL PROCEDURE
TEST RESULT
Press HLD.
Mode annunciator alternates between
MAP and HOLD.
Press HLD again.
Annunciator resumes a constant MAP
display.
MOST PROBABLE
CAUSE OF FAILURE
RTA, WXP
WX Mode Function Test
On WXP-840A/B, set range to 10 and
MODE to WX.
Antenna sweeps.
WXP, RTA
In addition to possible targets, display
shows range mark and WX mode annunciator.
Note
If a distant target such as a rain cloud or terrain feature is evident, adjust TILT control on WXP-840A/B for the best
(largest) display of that target. Otherwise, adjust tilt for a reasonable ground target display.
Targets are displayed in green, yellow,
red, and magenta.
ON WXP-840A/B, set RANGE to 25, 50,
100, etc.
WXP, RTA
Target(s) shift position on display according to range selected.
Note
Obviously, any target visible at 10 nmi will disappear into the vertex when the 100 or greater range is selected.
13.0
Press HLD.
MODE annunciator alternates between
WX and HLD.
Press HLD again.
Annunciator resumes a constant WX display.
WXP, RTA
AUTO Tilt Function Test
Note
The AUTO tilt function cannot be tested easily and reliably while the aircraft is on the ground.
14.0
PAC and PAC Alert Functions Test
Note
The PAC and PAC Alert functions cannot be tested easily and reliably while the aircraft is on the ground.
15.0
Gain Function Test
Set GAIN selector to first click ccw from
horizontal.
Size of target decreases.
WXP, RTA
G-1 is annunciated in upper left corner of
MFD and in lower left corner of ND.
Any contour area should decrease in size.
Set GAIN selector to second and then to
third click ccw from horizontal.
At each step, target size and intensity
level decreases.
G-2 or G-3 is annunciated.
28 April 1991
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installation 523-0775824
Table 2-12. Postinstallation Test Procedures.
TEST
NO.
15.0
(Cont)
MANUAL PROCEDURE
Set GAIN selector to first, second, and
third click cw from horizontal.
TEST RESULT
At each step, target size and intensity
level increases.
MOST PROBABLE
CAUSE OF FAILURE
WXP, RTA
G+1, G+2, or G+3 is annunciated.
Note
Each click of the GAIN adjustment from CAL to -3 effectively decreases the gain by about 6 dB. Each click of the GAIN
adjustment in the positive (+) direction has the effect of increasing the receiver gain by that same amount. This is
accomplished by decreasing the number of target illuminations required for a given target presence decision at ranges
beyond the STC range (approximately 50 nmi). GAIN CAL is the only gain selection in which a given rainfall rate
(Z-level) will be displayed at the proper display color for all ranges.
Set GAIN selector to CAL.
16.0
G+0 may be annunciated.
GCS Function Test
Press in GCS switch.
GCS is annunciated.
WXP, RTA
Number of ground targets is noticeably
reduced.
Release GCS switch.
Ground target display reappears.
Note
This completes the tests for installations with a single WXP-840A/B control. For dual system, repeat tests 10.0
through 16.0, using the right side control. Select SLV on the left side control and, during the course of the procedures,
note that the left side ND display agrees with that of the right side except that the mode annunciators are preceded by
an X (for cross-side). All other annunciators are the proper color according to the type of EFIS installed.
2.5 IN-FLIGHT STABILIZATION
ALIGNMENT PROCEDURES
2.5.1 Introduction
The in-flight stabilization alignment procedures
need not be performed if the following two conditions are otherwise satisfied:
1. The RTA-85X is installed with good mechanical accuracy so that the installation is well
within the requirements of paragraph 2.3.4.4,
Mechanical Alignment, and,
2. The installation uses a digital horizontal
reference system like the AHS-85/85E Attitude Heading System.
In those installations where the in-flight procedure is enabled for customer use, the radar
system Pilot’s Guide includes detailed instructions for in-flight alignment.
In all cases it is not intended that installers
28 April 1991
should make a special flight with the single
mission of performing these radar system alignment procedures. Rather, if the procedures are
needed, installers should integrate them into
other aircraft check-out flight operations.
In those segments of the alignment procedure
where straight and level flight is required, it is
best to use heading or manual flight mode. The
deviation in beam centering that is normal in
VOR and RNAV modes can detract from the
desired precision.
These stabilization alignment procedures are to
be performed in flight. The procedures calibrate
the WXR-840 system to the specific aircraft, and
especially to the vertical reference system, by
compensating for the remaining mounting errors.
The procedures utilize an alignment mode, built
into the RTA-84X, to introduce certain offsets
into the antenna roll and pitch attitude control
functions. These are stored in nonvolatile memory and, therefore, if done correctly, need be per2-25
installation 523-0775824
formed only once for a given equipment complement. If any part of the installation affecting
the stabilization system is changed or replaced,
the process must be repeated for that equipment.
In some installations, the stabilization alignment
feature may not be enabled. This procedure
cannot be performed unless a strap is connected
between WXP-840A/B rear connector pins J2-28
and J2-12.
The in-flight stabilization alignment procedures
are provided in paragraphs 2.5.3 (Table 2-14) and
in 2.5.4 (Table 2-15). The first is a more detailed
version that can be used to gain familiarity with
the process. For those experienced in the process, paragraph 2.5.4 is an abbreviated version
that requires less reading during the actual
procedure.
2.5.2 Alignment Controls
All the controls used for this procedure are on the
WXP-840A/B control panel. These are described
in the following paragraphs:
a. Stabilization Alignment Mode Activate Button
This is a recessed black pushbutton located at
the bottom center of the WXP-840A/B control.
Use this button to activate or deactivate the
stabilization alignment mode.
Refer to
Figure 3-1 in the operation section if necessary. Use a small probe, similar to a ballpoint pen, to press in on the button. Do not
use a lead pencil. Lead residue can cause
damage to the unit. When the stabilization
alignment mode is activated, TRIM is annunciated on the EFIS display. When one of the
adjustment parameters is selected by means
of the MODE switch, the selected parameter
is annunciated in place of TRIM. After one or
more of the parameters have been satisfactorily adjusted and stored in temporary memory
by means of the HLD button (see below),
pressing in on the recessed button enters the
parameters into permanent nonvolatile memory.
b. MODE Switch
The MODE switch is used to select the parameter to be adjusted, and the TILT control
is used to adjust that parameter. The switch
positions and the parameters thus selected
are summarized in Table 2-13.
c.
TILT Control Knob
The TILT control knob is used to adjust the
alignment parameter selected by means of the
MODE switch. The amount of adjustment
introduced becomes the electrical offset that
is used by the radar stabilization function.
d. HLD (Hold) Switch
The HLD switch is used to store the adjusted
value of the parameter into temporary radar
memory during the alignment process. There
are three adjustment parameters: roll offset,
pitch offset, and stabilization gain. Each of
these is adjusted separately and must be
entered into temporary memory before the
next parameter is selected.
2.5.3 Detailed In-Flight Alignment
Procedures
The detailed alignment procedures are provided
in Table 2-14.
2.5.4 Abbreviated In-Flight Alignment
Procedures
The abbreviated in-flight alignment procedures
are provided in Table 2-15.
28 April 1991
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Table 2-13. MODE Switch In-Flight Alignment Parameters.
MODE SWITCH POSITION
STABILIZATION ALIGNMENT MODE
WX
Selects roll offset for adjustment.
MAP
Selects pitch offset for adjustment.
TGT
Select stabilization gain for adjustment.
STBY
Discards any adjusted parameters, activates all alignment parameters stored in memory,
cancels alignment mode, and resumes normal operation.
TEST
Activates normal MAP mode to allow viewing of any radar target(s) using currently
adjusted alignment parameters not yet entered into memory.
OFF, then any mode
Regarding stabilization alignment, selecting OFF has the same effect as selecting STBY.
Pulling the primary power circuit breaker also has the same effect.
Table 2-14. Detailed In-Flight Stabilization Alignment Procedures.
STEP
NO.
PROCEDURE
DESIRED RESULT/DISPLAY
1.0
Before takeoff, be sure that stabilization alignment mode is enabled by a strap
between WXP-840A/B rear connector pins J2-28 and J2-12.
2.0
Before takeoff, position WXP-840A/B MODE switch to STBY and RANGE
switch to 50.
3.0
Complete all ground procedures for WXR-840 system installation and prepare
aircraft for flight.
Note
You may want to delay the following step until immediately before starting the alignment procedures (step 10.0).
This allows the full compass rose format to be used during takeoff and climbout.
4.0
For EFIS installations with an MFD, push PWR and RDR buttons.
For EFIS installations without an MFD, place ND in a sector format that
allows radar display.
5.0
After takeoff, select MAP mode.
6.0
Climb to normal cruise altitude and trim aircraft.
7.0
Wait about 5 minutes, with no roll or pitch changes, for attitude reference
system to stabilize. Use heading or manual flight mode.
8.0
If not already done, select MAP MODE. (Be sure GCS is not selected.)
9.0
Adjust TILT and RANGE. Depending on cruise altitude, select range that
gives best half-range ground clutter ring with least downward tilt.
10.0
If not already done in step 4.0:
Adjust so that near edge of
ground clutter ring is aligned
with EFIS half-range arc.
For EFIS installations with an MFD, push PWR and RDR buttons.
For EFIS installations without an MFD, place ND in a sector format that
allows radar display.
28 April 1991
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installation 523-0775824
Table 2-14. Detailed In-Flight Stabilization Alignment Procedures.
STEP
NO.
PROCEDURE
DESIRED RESULT/DISPLAY
Note
In the following step you will activate the stabilization alignment mode by using a probe to depress the recessed
switch. Do not use a lead pencil. Lead residue can cause damage to the mechanical switches and can cause short
circuits.
11.0
Activate alignment mode by depressing recessed black button at bottom center
of WXP-840A/B control panel.
Note
During the course of this procedure, STBY can be used at any time to erase any adjusted parameters and return to
the value stored in permanent memory. For new installations, the stored values may be zero for all parameters.
12.0
Select WX MODE.
This selects roll offset for adjustment.
13.0
Adjust TILT.
Adjust for best left/right symmetry of ground return display.
14.0
Press HLD momentarily to store adjusted value in temporary memory.
15.0
Select MAP MODE.
This selects pitch offset for
adjustment.
16.0
Adjust TILT.
Adjust so that near edge of
display is at a constant distance display arc.
17.0
Press HLD momentarily to store adjusted value in temporary memory.
18.0
Select TGT MODE.
19.0
Place aircraft into, and maintain, a shallow bank (10° to 15°, either left or
right).
This select stabilization gain
for adjustment.
Note
Prolong flight at a constant bank angle can cause precession in some gyro systems. Therefore, this attitude should
not be maintained for more than a few minutes. Additionally, after resuming straight and level flight, it is wise to
wait a few minutes for the gyro system to be corrected.
20.0
Adjust TILT.
21.0
Press HLD momentarily to store adjusted value in temporary memory.
22.0
At this point, select TGT MODE and any desired RANGE to view any radar
target display before storing adjusted parameters in permanent memory.
28 April 1991
Adjust for best lest/right symmetry of ground return display.
2-28
ADDENDUM 7
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, 1ST EDITION, DATED 27 APRIL 1991
Insert this addendum sheet facing page 2-29
of the Installation Section (523-0775824-001118)
Table 2-16 contains an In-Flight Stabilization Alignment Procedure for AMS-5000 Equipped Beechjet 400A.
Table 2-16. In-Flight Stabilization Alignment Procedure for AMS-5000 Equipped Beechjet 400A
STEP
NO
PROCEDURE
1
Fly to cruise altitude (15k to 30k feet). Fly in HDG or ROLL mode for wings level
flight over known level terrain.
2
Select RANGE 50 and MAP mode.
3
Enter the STAB TRIM mode by pressing the STABILIZATION TRIM line key on CDU
Radar page 2.
Enter WXSETUP in the scratchpad and press the ENTER PASSWORD line key.
DESIRED RESULT/DISPLAY
The STAB TRIM page should now be
displayed on the CDU.
Note
Leaving the STAB TRIM page for any
reason, such as going to a TUN page, will
end the STAB TRIM without saving any
settings and the process must be started
over.
4
Adjust TILT for ground returns at about 25 miles.
5
Press the ROLL OFFSET line key to display the ROLL OFFSET page.
Adjust the TILT knob for an equal amount of ground returns on the left and right
sides of the display.
Press TEMPORARY CAPTURE line key when satisfied.
6
Press the PITCH OFFSET line key to display the PITCH OFFSET page.
Adjust the TILT knob for returns in the center and returns on the left/right to be equal
distance.
Set for best arc shape, not egg-shaped or
flat. The picture should stay the same with
the aircraft nose up or down.
Press TEMPORARY CAPTURE line key when satisfied.
7
Use ½ BANK to set up and maintain a 10° to 15° bank angle.
8
Press the ROLL GAIN line key to display the ROLL GAIN page.
Adjust the TILT knob for equal amount of ground returns on the left and right sides
of the display.
Press the TEMPORARY CAPTURE line key when satisfied.
9
Repeat any adjustments as necessary.
Press the CAPTURE line key to permanently store the new settings or press the
CANCEL line key to exit the STAB TRIM mode without saving.
10
Observe the radar display in normal flight for proper stabilization. Repeat the above
adjustments as necessary.
Addendum 7
23 May 1999
523-0775822-07111A
Sheet 1 of 1
(Facing Page 2-29)
installation 523-0775824
Table 2-14. Detailed In-Flight Stabilization Alignment Procedures.
STEP
NO.
PROCEDURE
23.0
If, for any reason, you want to readjust a parameter, select MODE switch
position corresponding to desired parameter and readjust TILT as necessary.
Press HLD to store adjusted value in temporary memory.
24.0
If, for any reason, you want to restart procedure, select STBY to discard any
adjusted values and return to step 8.0.
25.0
If you are satisfied that the adjustments are the best that can be obtained,
press recessed button to store adjusted values in permanent memory and exit
stabilization alignment mode.
DESIRED RESULT/DISPLAY
Table 2-15. Abbreviated In-Flight Stabilization Alignment Procedures.
STEP
NO.
PROCEDURE
DESIRED RESULT/DISPLAY
1.0
After arriving at cruise altitude, trim aircraft for straight and level flight. Use
heading or manual flight for straight and level flight.
2.0
Select RANGE 50 and MAP MODE.
3.0
Adjust TILT.
Adjust for ground return at
about 25 nmi.
4.0
Press recessed button.
This activates alignment
mode
5.0
Select WX, adjust TILT, and press HLD to save.
Adjust for left/right symmetry of display.
6.0
Select MAP, adjust TILT, and press HLD to save.
Adjust for uniform distance
to display edge.
7.0
Set up and maintain a constant aircraft bank altitude of about 10° to 15°.
8.0
Select TGT, adjust TILT, and press HLD to save.
9.0
Trim aircraft for straight and level flight.
10.0
Repeat as necessary:
Adjust for left/right symmetry of display.
a. Select STBY.
b. Go back to step 2.0.
or
Return to step 5.0, 6.0, or 7.0
11.0
Press recessed button.
28 April 1991
2-29
installation 523-0775824
Use of Crimp and Insertion Tools
Figure 2-2
28 April 1991
2-30
installation 523-0775824
RTA-84X and WXP-840( ) Mating Connector Assembly
Figure 2-3
28 April 1991
2-31/(2-32 blank)
installation 523-0775824
WXR-840 Advanced Weather Radar System,
Interconnect Wiring Diagram
Figure 2-4 (Sheet 1 of 3)
28 April 1991
2-33/(2-34 blank)
installation 523-0775824
WXR-840 Advanced Weather Radar System,
Interconnect Wiring Diagram
Figure 2-4 (Sheet 2)
28 April 1991
2-35/(2-36 blank)
installation 523-0775824
WXR-840 Advanced Weather Radar System,
Interconnect Wiring Diagram
Figure 2-4 (Sheet 3)
28 April 1991
2-37/(2-38 blank)
ADDENDUM 6
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, 1ST EDITION, DATED 27 APRIL 1991
Insert this addendum sheet facing page 2-39
of the Installation Section (523-0775824-001118)
In Figure 2-5, the description for pin 31 of the RTA-840 mating connector does not completely show the functions
provided on this pin for attitude input.
The description for pin 31 should read as follows:
31
ARINC 429 12.5 kBd / 100 kBd DIGITAL OR
50 mV/DEGREE / 200 mV/DEGREE
ANALOG ATTITUDE INPUT
The line over the description indicates that the pin is connected to pin 12, PROGRAM COMMON.
Addendum 6
20 May 1999
523-0775822-06111A
Sheet 1 of 1
(Facing Page 2-39)
installation 523-0775824
RTA-84X Receiver/Transmitter/Antenna Connector J1 Pin Assignments
Figure 2-5
28 April 1991
2-39
installation 523-0775824
WXP-840( ) Weather Radar Panel, Connector J1 Pin Assignments
Figure 2-6 (Sheet 1 of 2)
28 April 1991
2-40
installation 523-0775824
WXP-840( ) Weather Radar Panel, Connector J1 Pin Assignments
Figure 2-6 (Sheet 2)
28 April 1991
2-41/(2-42 blank)
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
WXR-840 Advanced Weather Radar System
INSTALLATION MANUAL (523-0775822, 1ST EDITION, DATED APR 28/91)
TEMPORARY REVISION NO. 08
Insert facing page 2-43.
Subject: Replace Figure 2-7.
Temporary Revision 8
523-0775822-08111A
Page 6
Feb 2/01
installation 523-0775824
RTA-84X Receiver/Transmitter/Antenna,
Outline and Mounting Diagram
Figure 2-7
28 April 1991
2-43
installation 523-0775824
RTA-84X Antenna to Aircraft Axis Mounting Diagram
Figure 2-8
28 April 1991
2-44
installation 523-0775824
RTA Mounting Hole Pattern Diagram
Figure 2-9
RTA Mounting Hole Alignment Bar
Figure 2-10
28 April 1991
2-45
installation 523-0775824
Use of Alignment Bar Diagram
Figure 2-11
28 April 1991
2-46
installation 523-0775824
WXP-840A Weather Radar Panel,
Outline and Mounting Dimensions
Figure 2-12
28 April 1991
2-47
installation 523-0775824
WXP-840B Weather Radar Panel,
Outline and mounting dimensions
Figure 2-13
28 April 1991
2-48
installation 523-0775824
Wire Marking Strandard
Figure 2-14
28 April 1991
2-49
installation 523-0775824
WXR-840 System Input/Output Circuits
Figure 2-15 (Sheet 1 of 4)
28 April 1991
2-50
installation 523-0775824
WXR-840 System Input/Output Circuits
Figure 2-15 (Sheet 2)
28 April 1991
2-51
installation 523-0775824
WXR-840 System Input/Output Circuits
Figure 2-15 (Sheet 3)
28 April 1991
2-52
installation 523-0775824
WXR-840 System Input/Output Circuits
Figure 2-15 (Sheet 4)
28 April 1991
2-53/(2-54 blank)
ADDENDUM 4
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet and following sheets
with Figure 2-17 and Figure 2-18 after Page 2-54
of the Installation Section (523-0775824-001118)
Insert new Figure 2-16 (Sheet 1).
Figure 2-16 (Sheet 1 of 2). WXA-850A Weather Radar Adapter (CPN 822-0053-001),
Installation Control Drawing
Addendum 4
30 May 1998
523-0775822-04111A
Sheet 6 of 9
(Following Page 2-54)
ADDENDUM 4
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert new Figure 2-16 (Sheet 2).
Figure 2-16 (Sheet 2 of 2). WXA-850A Weather Radar Adapter (CPN 822-0053-001),
Installation Control Drawing
Addendum 4
30 May 1998
523-0775822-04111A
Sheet 7 of 9
ADDENDUM 4
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert new Figure 2-17
Figure 2-17. WXA-850A Control Adapter Mount (CPN 827-5060-001),
Component Location Diagram
PARTS LIST
MOUNT, CONTROL ADAPTER, CPN 827-5060-001 (REV –)
SYMBOL DESCRIPTION
–
1
2
3
4
5
6
7
8
Mount, control adapter
Strap, mounting
Spring, conical
Clamp, mounting
Nut, special
Retainer, nut, special
Screw, .112-40 X .19 (qty 2)
Screw, .138-32 X .375 (qty 5)
Washer, lock, No. 6 (qty 5)
Addendum 4
30 May 1998
523-0775822-04111A
USED
ON
CODE
COLLINS
PART
NUMBER
827–5060–001
827–5053–001
634–1519–002
827–5058–001
653–1299–001
653–2142–001
342–0043–000
343–0169–000
310–0282–000
Sheet 8 of 9
ADDENDUM 4
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert new Figure 2-18
Figure 2-18. WXA-850A Control Adapter Mount (CPN 628-9865-001),
Component Location Diagram
PARTS LIST
MOUNT, CONTROL ADAPTER, CPN 628-9865-001 (REV –)
SYMBOL DESCRIPTION
–
1
2
3
4
5
6
7
10
11
Mount, control adapter
Strap, mounting
Spring, conical
Clamp, mounting
Nut, special
Retainer, nut, special
Screw, .112-40 X .19 FLH (qty 2)
Screw, .138-32 X .75 PNH
Washer, lock, No. 6 (qty 5)
Nut, hex, lock, No. 6
Addendum 4
30 May 1998
523-0775822-04111A
USED
ON
CODE
COLLINS
PART
NUMBER
628–9865–001
628–9866–001
634–1519–002
628–9867–001
653–1299–001
653–2142–001
342–0043–000
343–0174–000
310–0282–000
846–2016–010
Sheet 9 of 9
III
section
operation
3.1 WEATHER RADAR SYSTEM
OPERATION
the WXR-840 system operating mode, range, tilt,
etc, for display on their respective NDs (Navigation Displays).
This section provides information for a basic
understanding of the operation of the WXR-840
Advanced Weather Radar System.
Figure 3-1 shows the WXR-840 Advanced Weather Radar System operating controls. All operating controls for the WXR-840 Advanced Weather
Radar System are located on the WXP-840A or
WXP-840B Weather Radar Panel. The installation can feature either one or two WXP-840A/B
panels. This optional dual control capability
allows the pilot and copilot to individually select
3.1.1 Introduction
The WXP-840A/B Weather Radar Panel provides
the data processing, mode control, range selection, and other system operating controls for the
WXR-840 Advanced Weather Radar System.
Weather radar information from the WXP-840A/B
is displayed on the MFD (MultiFunction Display;
refer to Figure 3-2) or the NDs (Navigation
Displays) which are part of the Collins EFIS
(Electronic Flight Instrument System).
WXP-840A/B Control Functions
Figure 3-1
28 April 1991
3-1
operation 523-0775825
The WXR-840 system provides the following
display and performance features:
a. A 4-color weather display: green, yellow, red,
and magenta, plus the black screen itself
b. PAC (Path Attenuation Correction), with a
PAC Alert arc appearing in yellow at the
perimeter of the display
c. GCS (Ground Clutter Suppression)
d. SLV (SLaVe) switching for use when two
indicators (such as both NDs or an MFD and
an ND) and two WXP-840A/B controls are
installed
e. AUTO (AUTOtilt)
f. Sector scan
g. In-flight stabilization/alignment mode (installation option)
The following paragraphs describe the WXP840A/B operating controls.
Note
The colors of weather radar mode annunciators, arc format, and map format depend on the type of EFIS display being
used. Refer to the appropriate EFIS manual for annunciator, arc format, and map
format colors.
3.1.2
MODE Control
The MODE control is a rotary switch used to
select the various operating modes of the WXR840 system. The MODE control switch positions
and the corresponding modes are as follows.
3.1.2.1 OFF
OFF mode removes power from the RTA-84X
Receiver/Transmitter/Antenna and WXR-840A/B
Weather Radar Panel. OFF will be displayed on
the MFD.
3.1.2.2 STBY (Standby)
In STBY mode, power is applied to the RTA-84X
Receiver/Transmitter/Antenna with a short (approximately 3-second) initialization period. During the initialization process, the RTA drives its
antenna to the boresight position (0° azimuth and
0° tilt). The antenna will remain in this position
as long as STBY is selected. The weather display, radar transmitter, and, after initialization,
28 April 1991
antenna scan drive circuits, are inhibited whenever STBY is selected. Approximately 20 seconds
after turning the MFD PWR switch on, one range
arc, airplane symbol, compass sector, and STBY
should appear on the MFD. It may be necessary
to adjust the INT (intensity) control on the MFD.
3.1.2.3 TEST
TEST mode initiates the radar self-test function
and causes the radar self-test display to appear.
TEST is annunciated on the MFD.
The radar self-test display is graphically described in Figure 3-2 and consists of six colored
arcs evenly spaced across the full sector of the
display. Each arc verifies the system’s ability to
process and display the precipitation intensity
level or other display data that is normally represented by that color. At the apex, occupying a
range approximately equal to two of the color
bands, are two arcs of black which represent no
detectable moisture. Progressing outward, the
colored arcs proceed as green, yellow, red, magenta, a ring that alternates between red and magenta, and, finally, an outer band of yellow. The
green band represents the first level of precipitation. The first band of yellow represents the
second level of precipitation intensity, while the
outer band represents PAC Alert. Red is used for
the third level of intensity, and magenta is used
for the most intense precipitation level.
3.1.2.4 TGT (Target Alert)
TGT mode permits weather targets to be detected
and annunciated without the targets themselves
appearing on the weather radar display. This
mode is normally used when other data (eg,
checklists, remote data, etc) is being displayed on
the MFD.
When TGT mode is selected, the radar transmitter is energized, the antenna scans, TGT (mode)
is annunciated, and, box with TGT inscribed
appears non-flashing to the right of the lubber
line or the digital heading readout. The target
alert mode notifies the pilot when a weather
target that is producing rainfall rates greater
than 0.5 inch/hour within 7 to 200 nmi and ±15°
of dead ahead is detected. The boxed TGT annunciator will flash when preceding target conditions are detected within the target alert window,
regardless of the range selected.
3-2
operation 523-0775825
WXR-840 Advanced Weather Radar System, Typical Self-Test Pattern
Figure 3-2
This flashing annunciation indicates to the pilot
that a severe precipitation rate has been detected. When this occurs, the pilot should select the
weather mode and RDR should be selected or the
MFD, or the NDs should be placed in a format
that allows weather to be displayed.
3.1.2.5 MAP
Selecting MAP mode automatically disables the
PAC Alert and GCS features. Map format, range
annunciators, ground targets, and MAP will be
displayed. MAP will be displayed in the upper
left of the MFD.
3.1.2.6 WX
Selecting WX mode allows the weather radar
system to operate in the weather detection mode.
Detectable weather is color coded; detectable
28 April 1991
weather above the minimum display threshold
appears as one of four colors: green, yellow, red,
or magenta (in the order of least reflective to
most reflective). (Refer to Table 3-2 for a reflectivity chart that shows the relationship between
reflectivity levels, precipitation rates, and displayed colors.) WX will be displayed in the upper
left of the MFD.
With WX mode selected, the PAC (Path Attenuation Correction) feature is automatically enabled.
The purpose of PAC is to compensate for the
radar beam absorption as it penetrates a given
precipitation cell. This overcomes the tendency
in non-compensated radar to underestimate the
true image of a precipitation cell simply because
the energy is absorbed as it penetrates the cell.
When radar targets are of sufficient magnitude
(intensity and depth) to exhaust the full range of
attenuation correction, a condition known as PAC
3-3
operation 523-0775825
Alert exists. PAC Alert highlights those sectors
of uncertainty which are masked by intervening
beam absorption. The bearing toward these
areas is shown by a yellow arc (bar) at the perimeter of the radar display (refer to Figure 3-3).
(For the WXR-840 system, the yellow PAC Alert
arc will appear when the system can no longer
detect a Z4 (red level) target at a range where Z3
(yellow level) targets would normally be detectable without intervening weather.) The pilot can
then recognize that, from his present position,
any precipitation in the sector between the
displayed weather and the yellow PAC Alert arc
may be underestimated and should be avoided.
Note
The PAC feature is intended for weather
detection modes only. Using a weather
detection mode and downward tilt to produce a ground map will probably produce
a display which makes correct interpretation more difficult. The PAC circuit will
interpret the return signals from ground
targets as intense storm targets and try
to compensate for the attenuated signal,
resulting in the yellow PAC Alert arc
appearing at the perimeter of the display.
In MAP mode, the PAC Alert feature is
automatically disabled.
3.1.3 GAIN Control
The GAIN control is a 7-position switch for
manual gain control of the radar receiver. When
placed in the CAL position, the gain is preset to
a value that allows the radar receiver to calibrate
its operation to the Z4 (red) return level. Each of
the minus settings (-1, -2, -3) reduces receiver
sensitivity below the CAL level by 6 dB for a
total reduction of 18 dB when in the -3 position.
Adjusting the GAIN control switch cw (ie, in the
+ direction) has the effect of increasing the
system sensitivity by appropriating sensitivity
factors from other features. For example, within
the STC range, the normal receiver sensitivity
reduction for STC is partially or wholly canceled
in order to effect an increase in receiver sensitivity. At ranges beyond STC, the various rainfall rate threshold levels are reduced or narrowed
to give the appearance of an increase in sensitivity.
28 April 1991
The GAIN control can be used in the MAP and
WX modes. The display color of a target depends
on the GAIN setting currently being used. In WX
mode and with the GAIN control in the CAL
position, all detectable targets are shown in the
following four colors: green, yellow, red, and
magenta (least reflective to most reflective). In
MAP mode and with the GAIN control in the CAL
position, all detectable targets are shown in four
colors.
The selected GAIN is annunciated (G-1, G+3, etc)
in the upper left of the MFD. In the CAL position, G+0 may be annunciated.
3.1.4 TILT Control
The radar antenna is fully stabilized to compensate for aircraft pitch and roll attitude changes.
The TILT control allows adjusting the vertical
aim of the radar antenna from approximately 15°
down to 15° up from horizontal. When stabilization (STB) is on, the combined TILT and stabilization control range is from 30° down to 30° up.
The tilt angle, in fourths of a degree with the
hundredth’s digit rounded off (eg, +10.7, -5.2,
etc), is annunciated on the MFD.
3.1.5 RANGE Control
The RANGE control is a rotary switch that is
used to select the maximum display range of the
WXR-840 system. All of the selectable ranges
provide one range arc in the center of the MFD
and ND (if weather radar is selected on the ND’s
control panel along with a sector format) with
half-scale range annunciation at the right-hand
end of the range arc and full range annunciation
at the outer range arc. The selectable ranges and
range mark annunciations are shown in
Table 3-1.
Table 3-1. Selectable Ranges and Annunciation.
SELECTED RANGE,
nmi (MAXIMUM)
RANGE MARK
ANNUNCIATION
5
10
25
50
100
200
300
2.5
5
12.5
25
50
100
150
3-4
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
WXR-840 Advanced Weather Radar System
INSTALLATION MANUAL (523-0775822, 1ST EDITION, DATED APR 28/91)
TEMPORARY REVISION NO. 08
Insert facing page 3-5.
Subject: Revise table
In Table 3-2, delete the column “REFLECTIVITY LEVEL”, the result of which is shown below:
Table 3-2. Reflectivity Chart.
PRECIPITATION RATE
COLOR
in/hr
mm/hr
less than 0.03
Less than 0.762
Black
0.03 to 0.15
0.762 to 3.81
Green
0.15 to 0.5
3.81 to 12.7
Yellow
0.5 to 2.0
12.7 to 50.8
Red
2.0 and greater
50.8 and greater
Magenta
Temporary Revision 8
523-0775822-08111A
Page 7
Feb 2/01
operation 523-0775825
Table 3-2. Reflectivity Chart.
PRECIPITATION RATE
REFLECTIVITY
LEVEL
in/hr
mm/hr
COLOR
Z1 = <20 dBz
less than 0.03
Less than 0.762
Black
Z2 = >20 dBz
0.03 to 0.15
0.762 to 3.81
Green
Z3 = >30 dBz
0.15 to 0.5
3.81 to 12.7
Yellow
Z4 = >40 dBz
0.5 to 2.0
12.7 to 50.8
Red
Z5 = >50 dBz
2.0 and greater
50.8 and greater
Magenta
PAC Alert Radar Display
Figure 3-3
3.1.6 GCS (Ground Clutter Suppression)
Pushbutton
The ground clutter suppression feature is enabled
by pressing the GCS button and is available only
in the wx mode. When selected, GCS reduces the
intensity of ground returns so that most of them
disappear from the display, allowing better
definition of precipitation targets. Any MODE or
RANGE change automatically cancels GCS. At
system power-up, GCS is not selected. GCS
should only be used to help differentiate weather
returns from ground returns (clutter). When
selected, GCS is enabled for approximately 12
seconds, after which normal operation is restored
automatically. A special strap is used at installation to select a feature called "Instant GCS."
When selected, this feature allows fast removal of
28 April 1991
ground return display.
When not selected,
ground display is removed at the normal antenna
sweep rate.
When selected, GCS is annunciated on the MFD.
3.1.7 SLV (SLaVe) Pushbutton (Not present
on some systems)
The slave mode is enabled by pressing the latching push-on/push-off SLV button so that the
feature is selected (button in). The SLV mode is
used only in those installations that have dual
WXP-840A/B panels. Therefore, in SLV operable
systems, pressing the SLV button on one WXP840A/B selects the slave mode and causes the ND
on that side to display the MODE, RANGE, TILT,
and GAIN selected by the other WXP-840A/B in
3-5
operation 523-0775825
the installation. (Weather radar must be selected
on the ND’s control panel along with a sector
format.) System control is then accomplished by
the other WXP-840A/B (the one without SLV
selected). Selecting SLV on both WXP-840A/B
panels places the WXR-840 in the standby mode,
and STBY is annunciated on the MFD and the
NDs. Momentarily pressing the SLV button a
second time returns the system to normal operation.
manually for different altitudes or range selections. The normal procedure for using autotilt is
as follows:
3.1.8 STB (STaBilization) Pushbutton
When autotilt is on and a different range is
selected or the aircraft changes altitude, the
RTA-84X automatically tilts the antenna to
maintain the same relationship between beam
deflection and display. Altitude information is
internally derived. Pushing the AUTO switch
back to its "in" position turns off the autotilt
feature.
The latching push-on/push-off STB button enables or disables the radar antenna pitch and roll
stabilization circuits. This feature is disabled
only when a failure in the horizontal and/or
vertical reference system causes the radar system
to become unusable. STB is normally enabled
(button in).
If stabilization is not selected, USTB is annunciated on the MFD. If stabilization is selected,
there is no stabilization-related annunciation. If
there is an attitude fault, a flashing USTB is
annunciated.
3.1.9 HLD (Hold) Pushbutton
Pressing the non-latching HLD button (located
concentric with the GAIN control) interrupts
updating of the weather display on the MFD.
Updating is resumed when the HLD button is
pressed again; when a MODE, RANGE, GAIN,
GCS, SLV, or SEC change occurs; or when power
to the system is cycled (turned off and then
turned on again). The system powers up with
HLD mode not selected.
ln HLD mode, the weather radar annunciator in
the upper left corner of the MFD and at the left
end of the range mark on the ND alternates
between HOLD and the selected mode (HOLDWX-HOLD-WX, etc). The alternating words serve
to remind the pilot that the system is in the HLD
mode and the weather radar display is not being
updated.
3.1.10 AUTO (AUTOtilt) Switch
Autotilt is selected by pulling outward on the
AUTO switch (located concentric with the TILT
control). Autotilt is designed to reduce pilot
workload by reducing the need to readjust tilt
28 April 1991
a. Select WX or MAP mode and the maximum
range desired.
b. Adjust the TILT control so that a light band
of ground return is visible at the outer perimeter of the display.
c. Engage AUTOtilt.
Autotilt is annunciated with an A preceding the
tilt angle in fourths of a degree with the
hundredth’s digit rounded off (eg, A+10.7, A-5.2,
etc).
3.1.11 SEC (Sector) Pushbutton
The sector scan switch is a non-latching momentary switch located concentric with the RANGE
control. Sector scan is selected by pressing in on
the SEC switch. When SEC is thus selected, the
antenna azimuth scan angle is reduced from ±60°
on either side of the aircraft’s nose to ±30°. With
the antenna scan angle reduced by 50 percent,
the weather radar display update rate is doubled.
This feature can be effectively used for a more
careful study of dynamic conditions and is especially useful in aircraft which use two WXP840A/B’s. In such an installation, either panel
can select or cancel the reduced sector scan
function for the WXR-840 system. The system
powers up with SEC mode not selected.
SEC mode is annunciated by decreasing the
range mark to the new reduced sector scan area.
3.1.12 Fault Monitor
The fault monitoring function built into the
WXR-840 system has priority over any selected
mode. The word FAULT is annunciated and
alternates between FAULT and the selected mode
annunciation if a fault is detected anywhere in
the system. If the fault is in the form of an
3-6
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
WXR-840 Advanced Weather Radar System
INSTALLATION MANUAL (523-0775822, 1ST EDITION, DATED APR 28/91)
TEMPORARY REVISION NO. 08
Insert facing page 3-7.
Subject: Revise table
Revise data in Table 3-3 as shown below. Changes are in bold text.
Table 3-3. Table of Radar Display Versus Rainfall Rate.
WXR-840 ADVANCED WEATHER RADAR DISPLAY LEVELS VERSUS RAINFALL RATES
MFD OR
ND
DISPLAY
LEVEL
Magenta
Red
RAINFALL
RATE
(in/hr)
VIDEO INTEGRATED PROCESSOR (VIP)
CATEGORIES
VIP LEVEL
RAINFALL
RATE
(in/hr)
Extreme
6
Greater than 5.0
Severe turbulence, large hail,
lightning, extensive wind gusts and
turbulence
Intense
5
2.0 to 5.0
Severe turbulence, lightning,
organized wind gusts, hail likely
Very strong
4
1.02 to 1.97
Severe turbulence likely, lightning
Strong
3
0.48 to 0.98
Severe turbulence possible, lightning
Light to moderate turbulence
possible, lightning
Greater than 2.0
0.5 to 2.0
Yellow
0.15 to 0.5
Moderate
2
0.10 to 0.48
Green
0.03 to 0.15
Weak
1
0.01 to 0.10
Black
Less than 0.03
Temporary Revision 8
523-0775822-08111A
REMARKS
STORM
CATEGORY
Page 8
Feb 2/01
operation 523-0775825
interrupted communication link between the
RTA-84X and the WXP-840A/B, then the word
FAULT appears non-flashing. Temporary fault
conditions can be cleared by selecting STBY mode
and then returning the mode control to any other
operational selection. If this method does not
clear the fault, then the system should be turned
off and some type of repair action performed.
Caution
The WXR-840 Advanced Weather Radar
System has been designed to exhibit a
very high degree of functional integrity.
Nevertheless, the pilot must recognize
that it is not practical to provide monitoring for all failure conditions. However
unlikely, it is possible that erroneous
operation could occur without a fault
indication. It is therefore the responsibility of the pilot and/or copilot to detect
such an occurrence by continually assessing the reasonableness of the displayed
information and by monitoring returns
from known weather or terrain and crosschecking the displayed data against other
sources of weather information, such as
radio broadcasting stations, other pilots,
and visual sightings.
3.1.13 Other Operational Considerations
3.1.13.1 Precipitation Display Levels
The WXR-840 has been designed to accurately
detect and display precipitation. While it is not
uncommon for a weather radar system to detect
and display solid or dry objects, weather radar
should never be used for that purpose. Table 3-3
is an expansion of the reflectivity chart in
Table 3-2 and shows the relationship between the
displayed levels of the WXR-840 system, rainfall
rates, and VIP (Video Integrated Processor)
thunderstorm levels as used by the US national
Weather Service.
The table shows that the display color green
corresponds closely with the weather service VIP
level 1. Display color yellow corresponds with
VIP level 2. Display color red covers VIP levels
3 and 4, and magenta covers VIP levels 5 and 6.
Storm categories from strong to very strong with
rainfall rates up to approximately 2 inches/hour
are included in the red display level return, while
storm categories from intense to extreme and
rainfall rates greater than 5 inches/hour are
included in the magenta display level return.
The REMARKS column of the table suggests
Table 3-3. Table of Radar Display Versus Rainfall Rate.
WXR-840 ADVANCED WEATHER RADAR DISPLAY LEVELS VERSUS RAINFALL RATES
MFD OR
ND
DISPLAY
LEVEL
RAINFALL
RATE
(in/hr)
Magenta
Greater than 2.0
Red
0.47 to 2.0
VIDEO INTEGRATED PROCESSOR
(VIP) CATEGORIES
STORM
CATEGORY
VIP LEVEL
RAINFALL
RATE
(in/hr)
REMARKS
Extreme
6
Greater than 5.0
Severe turbulence, large hail, lightning, extensive wind gusts and turbulence
Intense
5
2.0 to 5.0
Severe turbulence, lightning, organized wind gusts, hail likely
Very strong
4
1.02 to 1.97
Severe turbulence likely, lightning
Strong
3
0.48 to 0.98
Severe turbulence possible, lightning
Light to moderate turbulence possible, lightning
Yellow
0.16 to 0.47
Moderate
2
0.10 to 0.48
Green
0.04 to 0.16
Weak
1
0.01 to 0.10
Black
Less than 0.04
28 April 1991
3-7
operation 523-0775825
what can probably be expected for each storm
category.
It is important to note that when the WXP840A/B GAIN control is in the CAL position and
a red target is being displayed, it cannot be
determined from the display alone if the red area
is a VIP level 3 or 4 storm. Likewise, if a magenta target is being displayed, it cannot be determined from the display alone if the magenta area
is a VIP level 5 or 6 storm. If this information is
necessary, it must be acquired during preflight or
from Flight Watch when in route. If WX mode is
selected and the display shows areas of magenta,
Table 3-3 shows that VIP level 5 or 6 storms can
be expected to be extremely hazardous, and the
pilot is cautioned that flight near these areas can
be hazardous and should be avoided.
Note
Proper use of the GAIN control allows the
experienced pilot to estimate rainfall
rates greater than a VIP level 3 (red) or 5
(magenta) return. Targets still being displayed in a reduced gain condition would
imply that hail and very heavy rainfall
are likely.
3.1.13.2 Signal Strength at the Target and
Propagation Attenuation
A limitation that must be understood involves
factors affecting the transmitted radar signal
strength at the target. A number of easily identifiable factors can be considered:
a.
b.
c.
d.
Propagation attenuation
Beam width
Transmitter output power
Radome transmissivity
As the transmitted radar beam radiates through
the atmosphere, it gradually weakens. This loss
of signal strength is called propagation attenuation and is due primarily to distance and intervening atmospheric conditions.
The second
factor, beam width, somewhat related to the first,
involves the degree to which the transmitted
energy is concentrated into a beam. The specifications for beam width generally relate to the
angle which encloses the power level between 50
and 100 percent of the peak power level of the
beam.
The third factor, transmitter output
28 April 1991
power, addresses the performance of the transmitter. Obviously, if insufficient energy is available at the radiating antenna, insufficient energy
will be available at the target and the performance of the radar system will be degraded. The
fourth item, radome transmissivity, has become
an increasingly important issue with the more
modern radar systems. The output power of
modern radar systems has been significantly
decreased compared to earlier systems. For
example, a typical weather radar system available about mid-century featured a power output of
several hundred kilowatts. The WXR-840 output
power is a nominal 25 watts. This dramatic
reduction in output power demands a compensating increase in overall performance efficiency,
largely in the form of increased receiver sensitivity and sophisticated signal processing.
A good analogy of weather radar operation is that
of operating a flashlight on a dark night. First,
consider beam focus; the sharper the focus of the
flashlight beam, the greater the distance at
which an object can be seen and the more detail
is observable in the illuminated object. The
reason for this is that the light energy is concentrated into a narrower cross-sectional area and
therefore a greater concentration of energy is
available at the target to be reflected back to the
observer. In radar, technology has yet to achieve
good narrow beam concentration in a small
antenna reflector. Hence, it is true today that
the larger the reflector, the narrower the beam,
and the narrower the beam the better the radar
performance. It is also true that the larger
reflector offers improved return signal reception.
In the case of the flashlight analogy, however,
your eye is able to distinguish the position of an
object even if it is on the fringe of the flashlight
beam. This part of the analogy does not hold in
radar. Radar is not able to detect, with precision,
that the reflected energy being detected may have
reflected from an object on the fringe of the radar
beam and hence is being diminished in its prominence because it is positioned outside the area of
greatest energy concentration. In a radar display, all detected objects are assumed to be at the
center of the beam. This can result in a slight
exaggeration in the size of a target.
Attenuation due to distance is a function of basic
physics as well as the design of the weather
radar antenna (beam width). The same conditions that cause the transmitted energy to be
3-8
BUSINESS AND REGIONAL SYSTEMS
INSTALLATION MANUAL
WXR-840 Advanced Weather Radar System
WXR-840 Advanced Weather Radar System
INSTALLATION MANUAL (523-0775822, 1ST EDITION, DATED APR 28/91)
TEMPORARY REVISION NO. 08
Insert facing page 3-8.
Subject: Revise table
Revise data in Table 3-3 as shown below. Changes are in bold text.
Table 3-3. Table of Radar Display Versus Rainfall Rate.
WXR-800 ADVANCED WEATHER RADAR DISPLAY LEVELS VERSUS RAINFALL RATES
MFD OR
ND
DISPLAY
LEVEL
Magenta
Red
RAINFALL
RATE
(in/hr)
VIDEO INTEGRATED PROCESSOR (VIP)
CATEGORIES
VIP LEVEL
RAINFALL
RATE
(in/hr)
Extreme
6
Greater than 5.0
Severe turbulence, large hail,
lightning, extensive wind gusts and
turbulence
Intense
5
2.0 to 5.0
Severe turbulence, lightning,
organized wind gusts, hail likely
Very strong
4
1.02 to 1.97
Severe turbulence likely, lightning
Strong
3
0.48 to 0.98
Severe turbulence possible, lightning
Light to moderate turbulence
possible, lightning
Greater than 2.0
0.5 to 2.0
Yellow
0.15 to 0.5
Moderate
2
0.10 to 0.48
Green
0.03 to 0.15
Weak
1
0.01 to 0.10
Black
Less than 0.03
Temporary Revision 8
523-0775822-08111A
REMARKS
STORM
CATEGORY
Page 9
Feb 2/01
operation 523-0775825
attenuated also affect the reflected (returning)
energy. As a rule of thumb, doubling the distance to a target reduces the strength of the
signal by a factor of 4 and in some instances by
a factor of 16. All airborne weather radars have
a maximum range for detecting any returns from
a storm that contains just 12.5 mm (approximately 1/2 inch)/hour rainfall. That distance is known
as the "avoidance range" and is a performance
index that results when certain standard conditions (specified by ARINC characteristic no 564-1)
are applied to the radar system performance
characteristics. Other factors, such as a poorly
designed radome or one that has been subjected
to poor maintenance care, will measurably degrade the theoretical avoidance range of the
airborne weather radar system.
The avoidance range of the WXR-840 Advanced
Weather Radar System is 280 nmi when used
with a 12-inch flat plate antenna. This means
that the radar system is capable of showing a
green return from a storm at 280 nmi that has a
level 3 rainfall rate of 12.5 mm/ hour, provided
the radar system is searching through dry air
and a good radome. Notice the result of attenuation due to distance on this theoretical target:
At 280 nmi, 12.5 mm (or 1/2 inch)/hour rainfall,
which is a VIP level 3 (or possibly 5; refer to
Table 3-3), the radar produces only a green
display on the MFD or ND, a full two levels less
than the true intensity level. In the WXR-840
system, STC (sensitivity time control) is used to
compensate somewhat for this condition. Obviously, there is a practical limit as to the amount
of correction that can be applied. In the WXR840 system, the limit is an optimized function of
the mode and maximum range selected.
3.1.13.3 Range Compensation
As previously discussed, attenuation due to
distance reduces the strength of radar signals.
As the aircraft approaches a storm, this type of
attenuation rapidly decreases, thus increasing
signal strength and giving the appearance on the
displays of rapid intensification of the target. At
ranges of approximately 65 nmi (with a 12- or
14-inch antenna) or 75 nmi (with an 18-inch
antenna), the weather radar system compensates
for this problem by its sensitivity time control
(STC) circuit. As the aircraft approaches a
storm, the returns displayed on the MFD or NDs
28 April 1991
will grow in intensity due to lessened attenuation
right up to the 65- or 75-nmi STC boundary.
From the STC boundary inward, the MFD or NDs
display a justified image that allows accurate
assessment (assuming attenuation due to precipitation is taken into account). For most radars,
targets beyond the STC boundary will not be
properly displayed according to the standard
relationship between return level and rainfall
intensity.
However, the WXR-840 provides
range-adjusted thresholds to help compensate for
this relationship at ranges beyond 65 or 75 nmi.
Pilots are well advised to remember that any
return (display level 1, 2, 3, or 4) from a storm at
a significant distance usually indicates extremely
high rates of rainfall and, as shown in the REMARKS column of Table 3-3, moderate to severe
turbulence can be expected. These areas of
rainfall should be avoided. As the aircraft approaches a target, the decrease in range causes
the target display intensity to increase. This
intensification may be the result of decreasing
range and not necessarily target intensification.
The second type of attenuation that can reduce
the performance of any X-band airborne weather
radar system is attenuation due to intervening
precipitation. Moisture, and especially rainfall,
deflects radar signals. This has the effect of
reducing the energy level available at a more
distant target and thus can be seen as signal
path attenuation. The amount of attenuation due
to precipitation depends entirely on the rainfall
rate.
For example, the WXR-840 Advanced
Weather Radar System, with its avoidance range
of 280 nmi in dry air, may not be able to detect a
VIP level 5 or 6 storm even at 125 nmi if there is
intervening rainfall. There are instances where
wide bands of moderate rainfall or narrower
bands of heavy rainfall can attenuate the transmitted energy to a point where it can no longer
detect rainfall beyond a certain point. This can
result in a display that would seem to indicate no
rainfall beyond that point when in fact it is not
known whether there is rainfall or not simply
because there is no "visibility" beyond that point.
These blind areas are caused by the inability of
the radar energy to penetrate the intervening
precipitation.
As an aid in the detection and avoidance of these
potentially hazardous blind areas, the WXR-840
system provides a PAC (Path Attenuation Correc3-9
operation 523-0775825
tion) feature. The purpose of PAC is to compensate for the radar beam attenuation as it penetrates a given precipitation cell. This overcomes
the tendency in non-compensated radar to underestimate the true image of a precipitation cell
simply because the radar energy is attenuated as
it penetrates atmospheric conditions ahead of the
object cell. When these radar targets are of
sufficient magnitude (intensity and depth) to use
up the full range of attenuation correction, a
condition known as "PAC Alert" exists. PAC
Alert informs the pilot when the radar encounters a target having rainfall rates heavy enough
to attenuate the beam so much that targets
behind it may be hidden. PAC Alert highlights
these areas of uncertainty by placing a yellow
PAC Alert arc at the outer perimeter of the radar
range being displayed and located along the
perimeter with respect to the bearing toward
these areas. The pilot can then recognize that,
from his present position, any precipitation in the
area between the displayed target(s) and the yellow PAC Alert arc(s) is undetectable and should
be avoided.
Note
In addition to the PAC Alert feature,
proper adjustment of the TILT control
allows the pilot to "see" radar shadows,
thus avoiding the mistake of trying to fly
through a thin spot that is actually the
heart of the storm. This adjustment
procedure is located in the operation
section of the pilot’s handbook.
The important thing to remember about attenuation due to precipitation is that the radar energy
may not be able penetrate a given precipitation
cell with enough energy remaining to give an
accurate assessment of any additional cell(s) that
may be lurking beyond. Of course, it is also
possible that a given single cell can be of sufficient depth and/or intensity that the radar is
unable to detect its full depth. Even with PAC
Alert, the pilot is cautioned never to assume that
an area behind heavy rainfall is clear of precipitation because the radar is showing a level 0
(black) return and/or the yellow PAC Alert arc is
not being displayed.
28 April 1991
3.1.13.4 Antenna Size
The WXR-840 Advanced Weather Radar System
is available with an 18-, 14-, or 12-inch flat-plate,
phased-array antenna. In most cases, the area
available within the radome of the aircraft determines which antenna can be used. Collins General Aviation Division recommends installing the
largest possible antenna that will fit into the
space available. The larger the antenna, the
narrower the beam width, and the better the
overall system performance.
Figure 3-4 shows the beam width relationship
between the 18-, 14-, and 12-inch antennas. (The
beam width angle shown on the drawing is not to
scale but the dimensions shown are correct.) The
commonly held concept of radar beam shape is
that the beam is a very narrow and parallel beam
(pencil beam). Note that the beam of energy
radiating from the antenna is actually coneshaped. The diagram also shows that the larger
the diameter of the antenna, the narrower the
beam width. The narrower beam width improves
the ability of the radar system to detect targets
at the longer ranges, minimize beam width
distortion, and improve detail on the display.
The radar system performance at lower altitudes
is also improved when a larger antenna (narrower beam width) is used. Figure 3-4 shows that a
radar system with a 12-inch antenna and at
40,000 ft and 0° tilt angle would probably show
ground targets at less than 100 nmi. With an
18-inch reflector and at the same altitude, the
ground return would probably not appear until
well over 100 nmi. The narrower beam allows a
more direct observation at the lower and midsections of a storm cell and reduces the display
clutter caused by ground targets.
The airborne weather radar system measures the
intensity of the precipitation in a storm cell by
the amount of signal reflected back from the
target. Therefore, all other factors being equal,
radar systems with different sized antennas may
not agree on the intensity of a given cell. This is
caused by the different level of energy available
at a given cell location simply because it is
spread over a larger area (in the case of the
3-10
operation 523-0775825
smaller antenna sizes). Note the beam width at
50 nmi for the 18-, 14-, and 12-inch antennas in
Figure 3-4. At 50 nmi, the 18-inch antenna produces a beam having a circular diameter of
approximately 5.2 nmi. At the same distance, the
14-inch antenna has a beam approximately 6.3
nmi in diameter, and the 12-inch antenna produces a beam approximately 7 nmi in diameter.
At this point, it is appropriate to introduce a phenomenon that is evidenced when a given radar
target transitions from being less than, to more
than, beam filling.
This is illustrated in
Figure 3-5. If a given cell which is less than
beam filling has a reflectivity of R, that same
cell, having grown to be beam filling, displays a
reflectivity of R4. The WXR-840 system compensates somewhat for this by comparing the
data received to that of a theoretical average.
The result of this comparison is used to adjust
the processing of that data and provide a more
uniform and consistent display as the average
cell transitions from being less than, to more
than, beam filling. Obviously, not every cell fits
this model exactly. Therefore, it is not uncommon for a given cell to appear to increase and/ or
decrease in intensity at various distances.
3.1.13.5 Aircraft Radomes
Although not part of the WXR-840 Advanced
Weather Radar System, the radome contributes
significantly to overall system performance. A
poorly designed, constructed, repaired, or maintained radome can blind the radar antenna,
resulting in poor transmission and reception of
signals. There are many instances where the
crew will squawk the radar as being inoperable
or weak when the problem is actually the radome.
28 April 1991
The average one-way transmission should not be
less than 90 percent for any continuous scan of
the antenna relative to the radome. The minimum transmissivity at any point should not be
less than 85 percent throughout the window area
of the basic radome, including any installed rain
erosion protection. (The window area is that
portion of the radome which is illuminated by the
antenna as the antenna is tilted and rotated in
azimuth to its mechanical limits.)
The addition of lightning protection devices and
trim finishes should not degrade the transmission
efficiency by more than 3 percent. When properly
applied, radome paint causes a loss of about 3.5
to 5 percent in transmissivity. Rubber boots,
when properly installed, present about a 5percent loss. If a boot is used, it must be adequately sealed to prevent moisture accumulation
between the boot and the radome surface. Plastic
boots usually present a loss of 20 to 50 percent,
which makes them totally unacceptable.
A radome not meeting the above requirements
will cause a reduction in weather radar detection
and definition. If there is reason to question the
transmissivity of the radome, it should be
checked by a reputable radome authority, such as
Cair Radomes, Plastics and Synthetics Division of
Norton Company, Akron, Ohio.
To further assist the pilot in selecting or evaluating a radome, refer to FAA Advisory Circular
43-14, Maintenance of Weather Radomes, in the
Collins Installation Practices Manual (CPN
523-0775254).
3-11
operation 523-0775825
Radar Antenna Reflector Size Versus Beam Width
Figure 3-4
28 April 1991
3-12
operation 523-0775825
Storm Cell Reflectivity, Beam Filling Versus Non-Beam Filling
Figure 3-5
28 April 1991
3-13/(3-14 blank)
IV
section
theory of operation
4.1 WEATHER RADAR SYSTEM THEORY
4.1.2 Physical Description
4.1.1 General
Refer to Figure 4-1. The WXR-840 system is a
second generation solid-state weather radar
system. The system consists of two separate
units: the RTA-84X Receiver/Transmitter/Antenna and the WXP-840A/B Weather Radar
Panel. EFIS indicators are used to display the
radar presentation.
This section provides an introduction to the
operation of the WXR-840 Advanced Weather
Radar System. The material begins with a brief
physical description. This is followed by a brief
outline of the purpose of weather radar. The
background paragraph provides peripheral information on weather radar in general and relates
this to the WXR-840 system. The theory of
operation is contained in paragraph 4.4. Detailed
circuit theory is provided in the individual repair
manuals.
The mechanical feature that distinguishes the
RTA-84X unit from earlier generation weather
radar designs is its 1-piece construction, combining the receiver, transmitter, and antenna into a
single unit. Refer to Figure 4-2. The forward
WXR-840 Advanced Weather Radar System, Overall View
Figure 4-1
28 April 1991
4-1
theory of operation 523-0775826
portion of this unit is the flat-plate antenna,
which is available in either 12-, 14-, or 18-inchdiameter models. The antenna size is the primary distinguishing feature between the RTA-842
(12-inch antenna), RTA-844 (14-inch antenna),
and RTA-848 (18-inch antenna) models. Directly
behind the antenna is the RF assembly, consisting of the transmitter and receiver. Mating the
antenna and receiver-transmitter eliminates the
need for a waveguide. The RTA (receiver/transmitter/antenna) assembly is mounted on the drive
assembly and therefore swings from left to right
as the system scans and points up or down for
tilt. The drive assembly contains the motors and
mechanical system for the scan and tilt functions
and is attached to the base assembly. The base
assembly is cylindrical in shape, about 15 inches
in diameter and slightly less than 2 inches in
depth. It serves as the mounting base and
contains the power supplies and signal processing
portion of the RTA-84X unit. The complete
RTA-84X assembly must be mounted on a forward bulkhead or radar antenna mounting
surface and enclosed by a radome. It is vital to
proper performance of any radar system that the
radome be at least 85 percent RF transparent.
Refer to Figure 4-3. The WXP-840A (panel
mount) or WXP-840B (Dzus mount) Weather
Radar Panel provides the operating control
functions. These units are normally mounted in
the instrument panel. The WXP-840A occupies a
space about 1.5 inches high and 6.2 inches wide.
The WXP-840B occupies a space about 1.88
inches high and 5.75 inches wide. The control
functions include MODE, GAIN, TILT, and
RANGE selection knobs, plus pushbuttons for
ground clutter suppression (GCS), slave mode
(SLV), and stabilization enable/disable (STB)
selection. The WXP-840A/B also supplies the
final data processing function to format the video
data as needed by the EFIS system.
RTA-84X Major Subassemblies
Figure 4-2
28 April 1991
4-2
theory of operation 523-0775826
WXP-840A and WXP-840B Weather Radar Panels, Front Panel View
Figure 4-3
28 April 1991
4-3
theory of operation 523-0775826
4.2 PURPOSE OF EQUIPMENT
4.3 BACKGROUND
detecting an echo reflected by a target. Because
the propagation velocity of a radio wave is known
and fairly constant*, the range to the target is
easily determined by measuring the time between
transmit and the arrival of the echo. By using a
fairly narrow beam of transmitted energy, the
direction (aim) of the radiating antenna is the
direction to the target.
Radar is an acronym derived from RAdio Detecting And Ranging. The technique involved is one
of transmitting a burst (pulse) of energy and
X-band weather radar depends on the reflective
character of water to provide visibility of rain or
wet hail. Dry precipitation generally does not
The WXR-840 Advanced Weather Radar System
provides the flight crew with a display of radardetectable precipitation along and within 60° on
either side of the flight path. Refer to Figure 4-4.
Precipitation Presentation on an EFIS Indicator
Figure 4-4
*The propagation velocity of a radio wave is generally recognized to be 12.359 microseconds/radar mile.
That is, it takes a signal 12.359 µs to travel 2 nautical miles, 1 mile out and one mile back. Therefore,
distance (radar miles) = time (microseconds) divided by 12.359 microseconds/radar mile.
28 April 1991
4-4
theory of operation 523-0775826
Table 4-1. Z-Level Rainfall Rate and WXR-840 System Display Colors.
REFERENCE
WXR-840 DISPLAY
Z LEVEL
dBZ
COLOR
Z1
<20
Not displayed
Z2
>20
Z3
RAINFALL RATES
in/hr
mm/hr
<0.03
<0.762
Green
0.03 to 0.15
0.762 to 3.81
>30
Yellow
0.15 to 0.5
3.81 to 12.7
Z4
>40
Red
0.5 to 2.0
12.7 to 50.8
Z5
>50
Magenta
2.0 to 5.0
50.8 to 127.0
6
>60
Magenta
5.0 to 8.0
127.0 to 203.2
Z
Table 4-2. VIP Categories and WXR-840 System Display Colors.
VIDEO INTEGRATED PROCESSOR
(VIP CATEGORIES)
CATEGORY
LEVEL
RATE
WXR-840
SYSTEM
DISPLAY
COLOR
RAINFALL
RATE (in/hr)
Not displayed
<0.04
VIP DEFINITION
Weak
1
0.01 to 0.10
Green
0.04 to 0.16
Light to moderate turbulence (is possible with)* lightning
Moderate
2
0.10 to 0.48
Yellow
0.16 to 0.47
Light to moderate turbulence (is possible with) lightning
Strong
3
0.48 to 1.02
Red
0.47 to 2.0
Severe turbulence (is possible with)
lightning
Very strong
4
1.02 to 1.97
Intense
5
2.0 to 5.0
Extreme
6
>5.0
Severe turbulence (is possible with)
lightning
Magenta
>2.0
Severe turbulence (is very likely with)
lightning, organized wind gusts, and
hail.
Severe turbulence (is certain with) large
hail, lightning, and extensive wind
gusts.
*Words in parenthesis are added for clarity.
provide a reliable reflectivity to X-band radio
wave energy. Fog, at virtually all densities, as
well as clouds, also do not provide a reliable echo,
probably because of the small size of the water
particles. It is for this reason that visual sightings of cloud formations may not appear on a
weather radar display.
The WXR-840 system is a color weather radar
system (ie, various colors are used to differentiate
between a number of target intensities). There
are two systems used in measuring relative
rainfall rate or weather intensities. The first is
28 April 1991
used most often by industry and refers to rainfall
rate in terms of a Z-level, which is a measure of
the rainfall reflectivity. In this system, rainfall
rate is occasionally expressed in terms of dBZ.
The second system is used by the US National
Weather Service. This system relates rainfall
rate and a measure of possible associated turbulence to a defined VIP (video integrated processor) category. Table 4-1 and Table 4-2 describe
these systems and show the color used by the
WXR-840 system to display rainfall intensity
within each of the defined levels or categories.
4-5
theory of operation 523-0775826
4.4 SYSTEM OPERATION
4.4.2 Block Diagram Theory of Operation
4.4.1 Introduction
Refer to Figure 4-5. The desired range and mode
is selected on the WXP-840A/B control panel. In
response to this manual selection, control data is
transmitted to the RTA via either of the three
ARINC 429 data input bus lines. This data is
received by the program control function. This
function is microprocessor controlled and, depending on the range and mode selected, sends
control information to the antenna scan and tilt
control circuits, the transmitter, the receiver, and
the data processing circuits.
Refer to Figure 4-5. The operation of the WXR840 system can be described in terms of the
following major functions:
a.
b.
c.
d.
e.
f.
g.
Manual interface
Electronic control
Scan and tilt control
Transmitter
Receiver
Data processing
Display control
The manual interface function consists of the
manual controls on the WXP-840A/B. The data
link between the WXP-840A/B and the RTA-84X
is in the form of a ARINC 453 digital data bus.
With power applied and WX (weather) mode
selected, the appropriate data is supplied to the
RTA-84X, which causes the process control to
enable the scan and tilt electronics and mechanism. This causes the RTA RF and antenna
assembly to scan (ie, to physically move in a
sweeping motion from side to side, 60° to either
side of straight ahead, as shown on Figure 4-4).
The tilt function moves the RTA assembly vertically (ie, up or down). The tilt function is both
automatic (for stabilization) and manual (for pilot
selectable antenna aiming). A total of 60° of tilt
deflection is available, 30° above and 30° below
horizontal. One-half of that amount is for manual tilt and the other half is for automatic stabilization. At the same time, the process control also
causes the transmit, receiver, and data processing functions to operate. The transmit function
involves the generation of the RF pulses that are
radiated by the antenna. The energy reflected
back to the antenna by the precipitant is detected
in the receive function. The resulting video
information is processed into a signal which
identifies the direction, intensity, and range of
the precipitation that produced the reflected
energy. This signal is supplied to the control
panel, which formats the signal suitable for use
in the EFIS processing and display function.
Thus, by synchronizing the antenna sweep with
the display, the pilot is presented with a radar
picture of the precipitation pattern along the
flight path.
28 April 1991
The scan and tilt control circuits drive the mechanical scan function, which sweeps the antenna
horizontally for scan and vertically for tilt.
Horizontal motion is a constant sweeping movement. The vertical movement depends on either,
or both, of two sources: manual tilt and automatic stabilization.
The objective of automatic
stabilization is to keep the antenna scan line
horizontal; it automatically adjusts the antenna
tilt (vertical aim) as needed in response to aircraft pitch and roll attitude changes. The manual tilt is supplied by the operator and depends on
the need to observe a particular precipitation
pattern at an antenna aim other than straight
ahead.
The transmitter function generates the energy
bursts that are radiated by the antenna. These
energy bursts are in the form of X-band pulses of
various widths, depending on the mode and range
selected, and at a repetition rate of 208 to 324
pulses per second in weather detection modes.
The energy level is a nominal 24 watts.
When the radiated energy encounters a sufficient
amount of wet precipitant (liquid water), a
portion of the energy is reflected back to the
antenna. This returned energy is directed into
the receiver by means of a special RF switching
device known as a duplexer. The receiver extracts the received signal from the other RF noise
which is usually present and supplies it to the
data processing function in the form of raw
(unprocessed) video data. The data processing
function uses this video data to generate the
ARINC 453 digital data which is supplied to the
ARINC 453 receiver function in the WXP-840( )
4-6
theory of operation 523-0775826
panel. The data contains all information necessary to properly display the location and character of the radar target: range, azimuth, and
intensity.
The raster timing and EFIS output driver function generates the main control signals needed by
the EFIS display device. These include the
retrace and clock signals. Integrated into this
signal pattern is the radar display information,
including the range mark(s) and text information
such as mode, range, tilt angle, and possible pilot
alert data.
The receiver function extracts various items of
information from this data input. Weather data,
such as precipitation targets, is stored in the
WXR data RAM devices. The other display items,
such as range, mode, tilt, and gain annunciation
parameters, are stored in the screen memory
circuits. The operating instructions are stored in
the program EPROM devices. The raster timing
WXR-840 Advanced Weather Radar System, Block Diagram
Figure 4-5
28 April 1991
4-7
ADDENDUM 5
TO
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
PART NUMBER 523-0775822-00111A, DATED 28 APRIL 1991
Insert this addendum sheet facing page 4-8
of the Theory of Operation Section (523-0775826-001118)
Add new Paragraph 4.4.4 just after Paragraph 4.4.3 Input and Output Circuits.
4.4.4. Optional WXA-850A operation
The optional WXA-850A receives system operating data and range bin data from the RTA-84X by way of
the ARINC 453 serial digital bus. Range bin data is reformatted, processed, and then stored in RAM to
compose the radar picture. During display update cycles, the entire data content is read from RAM and
converted to red, blue, and green video signals that are sent to the EFIS display. System operating data is
separated from the range bin data and sent to the EFIS display by way of a serial data bus. This
information is mode, range, gain, etc. that is stroke written onto the display over the raster image. The
WXA-850A generates all of the raster timing signals that control the video circuits in the EFIS display
during raster image part of the display update cycle.
Addendum 5
30 May 1998
523-0775822-05111A
Sheet 1 of 1
(Facing Page 4-8)
theory of operation 523-0775826
and EFIS output driver circuits provide the
display signals for the EFIS display. This data is
the EFIS raster timing data and the video display data.
The data for operation of the entire radar system
is generated by the CPU and supporting circuits.
This data is largely in response to the front panel
operating controls which are used to determine
mode, range, and the other operational parameters. The control data for the RTA-84X is formatted in the ARINC 429 transmitter circuits.
28 April 1991
4.4.3 Input and Output Circuits
Figure 2-15 in the installation section shows the
input and output circuits and system interface for
the RTA-84X and WXP-840A/B and the stabilization sources and affected EFIS. Sheet 1 of the
figure begins with the primary power inputs for
the RTA-84X and WXP-840A/B. Notice that the
MODE switch in the WXP-840A/B applies the
ground necessary to enable the power supply in
the RTA-84X but it does not affect its own power
supply.
4-8
V
section
maintenance
5.1 GENERAL
5.2 FLIGHT-LINE PERFORMANCE TEST
This section contains information necessary to
evaluate the performance capability of the WXR840 Advanced Weather Radar System. Throughout the remainder of the section, the term RTA84X should be understood as applying to either
the RTA-842, RTA-844, or RTA-848. Similarly,
the term WXP-840( ) should be understood as
applying to either the WXP-840A or the WXP840B. Where reference is intended to a specific
model, the specific model reference will be used.
5.2.1 Introduction
In performing flight-line maintenance on the
WXR-840 system it must be recognized that you
are dealing with a number of aircraft systems in
addition to the radar system. Those additional
systems can be summarized into the following.
a. EFIS: These are the DPU, MPU, EFD, MFD,
and either a DSP or a DCP and CHP, components of that system.
b. Attitude source: This system consists of the
gyro, 332D-11( ), or other type attitude source
(eg, AHS-85( )).
c. Radome: This is one of the most critical portions of the airframe affecting radar performance. Refer to paragraph 3.1.13.5 in the
operation section of this manual for more
discussion on radome requirements.
d. Aircraft wiring. After the radar system has
been successfully installed and has operated
satisfactorily, a failure in the aircraft wiring
generally appears as broken wires, loose
connections, frayed wires causing a short
circuit, etc. Intermittent system operation is
most often caused by this type of failure.
The flight-line performance test is for performance evaluation in the aircraft and will aid in
isolating a problem to a system component, the
RTA-84X, or the WXP-840( ).
28 April 1991
Warning
The area within the scan arc and within
0.65 meter (2 feet) of an operating WXR840 Advanced Weather Radar System can
be a hazardous area. Do not operate the
system in any mode other than standby
(STBY) or test (TEST) when the antenna
might scan over personnel within that
range. FAA Advisory Circular 20-68B
provides additional details on the radiation hazards associated with ground operation of airborne weather radar (refer to
the Collins Installation Practices Manual,
CPN 523-0775254).
Only authorized and qualified personnel should
be allowed to operate the WXR-840 Advanced
Weather Radar System. The flight-line performance test procedures are provided in Table 5-1.
In those cases where a test failure can be caused
by more than one LRU, the MOST PROBABLE
CAUSE OF FAILURE column lists the line replaceable units in the order of the greatest
likelihood of failure.
5.2.1.1 EFIS Cross-Side Switching
Typically, the MFD and the left side ND are controlled by the pilot’s (left) side controls (DCP-85
or DSP-85). If cross-side control switching is
provided, it is assumed that the operator is
familiar with that system’s operation. No attempt is made in this procedure to guide the
operator in that regard. Further, it is also
assumed that in dual WXP-840A/B installations
the MFD and left side ND radar displays are
controlled by the pilot’s WXP-840A/B, while the
right side ND radar display is controlled by the
right side WXP-840A/B.
5-1
maintenance 523-0775827
Table 5-1. Flight-Line Performance Test Procedures.
TEST
NO.
1.0
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Initialization
Make the following selections.
On WXP-840A/B (both sides if dual):
MODE - OFF
GCS - released
STB - released
GAIN - CAL
TILT - center (0)
AUTO - in (off)
HLD - not selected
SEC - not selected
RANGE - 5
Aircraft power - on
On MFD:
PWR - on
MODE - RDR
On DCP-85/DSP-85:
ARC or MAP format
Push RDR button.
Note
The colors of weather radar mode annunciators, arc format, and map format depend on the type of EFIS display
being used. Refer to the appropriate EFIS manual for annunciator, arc format, and map format colors.
Note
In dual installations, perform this procedure first from the left side WXP-840A/B. At the start of the procedure,
depress the SLV switch on the right side WXP-840A/B. During the course of the procedure, the right side ND display
should be identical to that of the left side except that the mode annunciation will be preceded by an X (eg, XWX,
XMAP, etc). Therefore, during the course of the procedure, it is wise to glance over to the right side display,
occasionally, to ensure that the displays agree. When this procedure for the left side is completed, it must be
repeated for the right side.
Stabilization
Off or null
Note
A portion of the test in this table can be performed inside the hanger.
2.0
Standby Test
On WXP-840A/B, left side, set MODE to
STBY.
28 April 1991
In approximately 20 seconds, the range
arc with (2.5) at right end of range arc,
airplane symbol at bottom center, compass sector, and STBY annunciator
appear.
EFIS, WXP, RTA
5-2
maintenance 523-0775827
Table 5-1. Flight-Line Performance Test Procedures.
TEST
NO.
3.0
MANUAL PROCEDURE
On MFD or ND, range annunciator
indicates the following:
RANGE
FULL
HALF
5
10
25
50
100
200
300
5
10
25
50
100
200
300
2.5
5
12.5
25
50
100
150
RTA, WXP
Self-Test
On WXP-840A/B, set RANGE to 25 and
MODE to TEST.
5.0
MOST PROBABLE
CAUSE OF FAILURE
Range Annunciator
On WXP-840A/B, set RANGE as follows:
4.0
TEST RESULT
On MFD or ND, antenna scans, test
pattern 120°, six color bands outward
beyond black around apex: green, yellow, red, magenta, red/magenta, and
yellow (red/magenta alternates colors
each scan sweep).
RTA, WXP
Set RANGE to 10 or 50 and then back to
25.
Test pattern erases and then begins to
redevelop.
WXP, RTA
Before pattern is complete, press HLD
(only once).
Test pattern development stops and annunciator alternates between HOLD
and TEST.
Press HLD again.
Test pattern resumes development and
annunciator is constant test.
Hold Test
Note
If the radome is installed, antenna operation cannot be observed. Unless it can be removed easily, you may skip this
test in favor of the outside-of-hanger tests, where the display is used to determine tilt operation.
6.0
TILT Control Test
On WXP-840A/B, set MODE to TEST and
RANGE to 25.
6.1
RTA, WXP
Adjust TILT cw from center.
Antenna tilts up and a positive tilt
angle is displayed on MFD or ND, 15°
max.
Adjust TILT ccw from center.
Antenna tilts down and a negative tilt
angle is displayed on MFD or ND, 15°
max.
Set MODE to STBY.
Antenna stops at boresight.
AUTO Tilt Annunciator Test
On WXP-840A/B, pull outward on AUTO
knob and adjust TILT.
Tilt angle is now shown prefixed with
an A (eg, A+10.0, A-2.5, etc).
WXP, RTA
Push in AUTO knob.
28 April 1991
5-3
maintenance 523-0775827
Table 5-1. Flight-Line Performance Test Procedures.
TEST
NO.
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Note
The following step applies only to installations with dual WXP-840A/B controls.
7.0
SLV Function Test
Note
Up to this point, all annunciations on the right side should have been in agreement with those on the left side except
that the mode annunciation was preceded by an X.
7.1
Right Side Test
Release SLV switch on right side WXP840A/B and depress left side SLV switch.
Repeat all tests, starting with test 2.0,
using right side WXP-840A/B.
Double SLV Default Test
8.0
Depress SLV switch on both WXP-840A/B
controls.
Note that all displays show that system
is in standby and antenna parks at
center scan.
EFIS, WXP, RTA
Set MODE on either WXP-840A/B to TEST.
Note that all displays show that system
remains in standby.
EFIS, WXP
STB Control Test
Note
In this step, a stabilization source input is required. There are three possible methods to supply this input:
1. Install the gyro on a tilt table and introduce the necessary input by tilting the gyro.
2. Use the RTA flight-line test fixture shown in Figure 5-3, and patch a simulated roll/pitch signal into the
RTA-84X.
3. On an AHS-85( ) equipped installation, actuate the STIM mode to supply one or more of the simulated pitch/roll
input signals.
Note
There should be no need to make an accurate measurement of this function. The objective is to ascertain that the
system responds to a roll and pitch input. However, if a stabilization problem is likely, perform the stabilization
accuracy test below.
8.1
Inside Hanger STB Control Test With Radome Removed
On WXP-840A/B, set MODE to TEST and
TILT to 0 (center).
Antenna scans.
Using one of the methods described in test
8.0, apply 4° to 8° of pitch-down input.
Antenna pitches up by amount of input.
On WXP-840A/B, release STB switch (STB
off).
Antenna returns to horizontal scan and
USTB is annunciated.
Set pitch input to zero (null).
There is no change in antenna scan
motion.
Press in on STB switch (STB on).
USTB is not annunciated.
28 April 1991
RTA, WXP
5-4
maintenance 523-0775827
Table 5-1. Flight-Line Performance Test Procedures.
TEST
NO.
8.1
(Cont)
MANUAL PROCEDURE
TEST RESULT
Apply 4° to 8° of roll right input (right
wing down).
Antenna tilts up when scan is to right
of center and down when scan is to left.
On WXP-840A/B, release STB switch (STB
off).
Antenna returns to horizontal scan and
USTB is annunciated.
Set pitch input to zero (null).
There is no change in antenna scan
motion.
Press in on STB switch (STB on).
USTB is not annunciated.
MOST PROBABLE
CAUSE OF FAILURE
RTA, WXP
Note
Unless any additional stabilization testing is necessary (test 9.0), disconnect any equipment or facility used in this
stabilization test and restore the installation to its normal configuration.
Note
This completes the in-hanger procedures for installations with a single WXP-840A/B. If desired, test 9.0 can be
performed to check the stabilization to its normal configuration.
8.2
Outside Hanger STB Control Test With Radome Installed
Situate the aircraft so that the radar has a
clear view, extending ideally for several
miles, and a reasonable horizontal and of
60° to 120°.
Warning
In the next step, The aircraft must be outside when the transmitter is turned on. Be certain that no personnel or
combustible materials are within the ±60° hazardous area and a few feet from the front of the aircraft. Be guided by
FAA Advisory Circular 20-68B (refer to the Collins Installation Practices Manual, CPN 523-0775254).
On WXP-840A/B, set MODE to WX and
RANGE to 10 or 25. Be sure GCS is not
selected.
RTA, WXP, stabilization system
Adjust TILT so that ground return is
shown at or near max distance.
Using one of the methods described in test
8.0, apply 4° to 8° of pitch down input.
Ground return disappears or moves
away from apex (antenna tilts up).
Release STB switch (STAB off).
Ground return moves back to earlier
position and USTB is annunciated.
Press in on STB switch (STAB on).
Ground return position does not change
and USTB is not annunciated.
Apply 4° to 8° of pitch-up input.
Ground return moves closer to apex of
display.
Set pitch input to zero (null).
Ground return moves back to earlier
position.
Apply 4° to 8° of roll right input (right
wing down).
Ground return moves away or disappears on right side of display and
moves closer on left.
28 April 1991
5-5
maintenance 523-0775827
Table 5-1. Flight-Line Performance Test Procedures.
TEST
NO.
8.2
(Cont)
9.0
MANUAL PROCEDURE
TEST RESULT
On WXP-840A/B, press in on STB switch
(STAB off).
Ground return moves back to earlier
position and USTB is annunciated.
Set roll input to zero (null) and press STB
switch (STB on).
Ground return remains and USTB is
not displayed.
MOST PROBABLE
CAUSE OF FAILURE
RTA, WXP, stabilization system
Stabilization Accuracy Test
Note
This test requires that the radome be removed and therefore should be seen as optional. This test is only required if
there is strong evidence of a stabilization accuracy problem.
On WXP-840A/B, set MODE to TEST.
Apply the following gyro inputs, using one
of the methods described in step 8.0.
Note
Use the electronic inclinometer to make the following measurements. Refer to Figure 2-1 in the installation section.
Antenna at boresight.
ROLL
PITCH
ANTENNA TILT
(Null)
(Null)
Up 10°
Down 10°
Down 10°
Up 10°
RTA
Manually swing antenna toward right stop
(toward right wing).
ROLL
PITCH
ANTENNA TILT
Right 10°
Left 10°
(Null)
(Null)
Up 8.7 ±0.2°
Down 8.7 ±0.2°
Note
If any of these tests were significantly out of tolerance and it is clearly not the result of misalignment or a
stabilization system failure, the RTA-84X should be returned for repair.
10.0
Target Alert Function Test
Set MODE to TGT.
Antenna sweeps and a boxed TGT appears in upper right corner of display.
RTA, WXP
No weather or ground clutter is displayed.
Note
If a radar target such as a fairly intense rain cloud is visible at a distance of at least 7 miles and within 15° of
straight ahead, it may cause the annunciator to flash. If such a radar target is not available in the area, it may not
be possible to make a reasonable test of the target alert function.
28 April 1991
5-6
maintenance 523-0775827
Table 5-1. Flight-Line Performance Test Procedures.
TEST
NO.
11.0
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Map Mode Function Test
Set Mode to MAP.
MAP is annunciated.
RTA, WXP
TGT from previous step disappears.
Range mark changes color.
Ground targets appear.
12.0
Select different range.
Ground targets become less pronounced
with grater ranges and tend to disappear into vertex at ranges of 200 and
300.
Press HLD.
Mode annunciator alternates between
MAP and HOLD.
Press HLD again.
Annunciator resumes a constant MAP
display.
WX Mode Function Test
On WXP-840A/B, set range to 10 and
MODE to WX.
Antenna sweeps.
WXP, RTA
In addition to possible targets, display
shows range mark and a WX mode
annunciator.
Note
If a distant target such as a rain cloud or terrain feature is evident, adjust TILT control on WXP-840A/B for the best
(largest) display of that target. Otherwise, adjust tilt for a reasonable ground target display.
Targets are displayed in green, yellow,
red, and magenta.
On WXP-840A/B, set RANGE to 25, 50,
100, etc.
WXP, RTA
Target(s) shift position on display according to range selected.
Note
Obviously, any target visible at 10 nmi will disappear into the vertex when the 100 or greater range is selected.
13.0
Press HLD.
MODE annunciator alternates between
WX and HLD.
Press HLD again.
Annunciator resumes a constant WX
display.
WXP, RTA
AUTO Tilt Function Test
Note
The AUTO tilt function cannot be tested easily and reliably while the aircraft is on the ground.
14.0
PAC and PAC Alert Functions Test
Note
The PAC and PAC Alert functions cannot be tested easily and reliably while the aircraft is on the ground.
28 April 1991
5-7
maintenance 523-0775827
Table 5-1. Flight-Line Performance Test Procedures.
TEST
NO.
15.0
MANUAL PROCEDURE
TEST RESULT
MOST PROBABLE
CAUSE OF FAILURE
Gain Function Test
Set GAIN selector to first click ccw from
horizontal.
Size of target decreases.
WXP, RTA
G-1 is annunciated. Any contour area
should decrease in size.
Set GAIN selector to second and then to
third click ccw from horizontal.
At each step, target size and intensity
level decreases.
G-2 or G-3 is annunciated.
Set GAIN selector to first, second, and
third click cw from horizontal.
At each step, target size and intensity
level increases.
G+1, G+2, or G+3 is annunciated.
Note
Each click of the GAIN adjustment from CAL to -3 effectively decreases the gain by about 6 dB. Each click of the
GAIN adjustment in the positive (+) direction has the effect of increasing the receiver gain by that same amount.
This is accomplished by decreasing the number of target illuminations required for a given target presence decision
at ranges beyond the STC range (approximately 50 nmi). GAIN CAL is the only gain selection in which a given
rainfall rate (Z-level) will be displayed at the proper display color for all ranges.
Set GAIN selector to CAL.
16.0
G+0 may be annunciated.
GCS Function Test
Press in GCS switch.
GCS is annunciated.
WXP, RTA
Number of ground targets is noticeably
reduced.
Press GCS switch again to release GCS
function.
Ground target display reappears.
Note
This completes the tests for installations with a single WXP-840A/B control. For dual system, repeat tests 10.0
through 16.0, using the right side control. Select SLV on the left side control and, during the course of the
procedures, note that the left side ND display agrees with that of the right side except that the mode annunciators
are preceded by an X (for cross-side). All other annunciators are the proper color according to the type of EFIS
installed.
5.3 FLIGHT-LINE ISOLATION
PROCEDURES
Table 5-2 is a list of equipment needed for the
flight-line fault isolation procedures. The test
fixtures are shown in Figure 5-1 and Figure 5-3
and are for local fabrication. The fixture in
Figure 5-1 allows access to the input/output
signals for the WXP-840A/B. Generally, the
presence of a signal at any of the test points can
28 April 1991
be seen as an indication that the source of the
signal is operational. Table 5-3 make use of this
fixture.
The fixture shown in Figure 5-3 provides access
to the input/ output signals of the RTA-84X. The
procedures in Table 5-4 make use of this fixture.
This fixture also provides access to the stabilization signals. These are not available at the
WXP-840A/B connector. If the complaint or fault
5-8
maintenance 523-0775827
isolation suggests a stabilization system failure,
it may be more expedient to diagnose the failure
at the RTA-84X rather than at the gyro location.
To use this fixture, however, it is necessary to
remove the radome. Because of the difficulty in
radome removal, it is best not to remove it unless
there is strong evidence of an RTA-84X failure.
Table 5-2. Equipment Required for In-Aircraft Fault Isolation.
ITEM
DESCRIPTION
COMMENTS
WXP-840( )/850( ) flight-line test
fixture
Refer to Figure 5-1.
For fault isolation in cockpit
RTA flight-line test fixture
Refer to Figure 5-3.
For fault isolation under radome and for
input of simulated stabilization signals
Oscilloscope
Tektronix 435 or equivalent
For signal analysis
Digital voltmeter
Any; 35 V dc max and 130 V ac max
For voltage measurement
Ammeter
Any; 5 A dc max
For current measurement
Table 5-3. Fault Isolation Procedures at the WXP-840A/B.
STEP
Setup
PROCEDURE
DESIRED TEST RESULT
PROBABLE CAUSE OF
FAILED TEST
Turn off aircraft power to radar system.
Remove WXP-840A/B from its normal location and connect test fixture (as shown in Figure 5-1)
between WXP-840A/B and aircraft wiring.
Be sure 28 V DC PWR ON/OFF switch on test set is set to OFF.
Connect dvm between +V and -V jacks.
Connect ammeter between HI-I and LO-I jacks.
Turn on power to radar and EFIS systems.
Set 28 V DC PWR ON/OFF switch to ON.
Set MODE switch to STBY.
REMOTE ON LED is on.
Note
Strapping Options LED indicators may light, depending on straps installed. A lighted lamp indicates an installed strap.
Input voltage
Measure input voltage.
+27.5 V dc, ±5 V dc
A/C power supply
Input current
Measure input current (press PUSH I
switch).
0.5 A max, 0.25 A min
WXP-840A/B
Lighting voltage
Connect dvm 28 V or 5 V LIGHTING
COMMON.
Depends on lighting used.
Lighted lamp indicates
voltage used.
Data bus (429)
Connect scope to CONTROL DATA
(ARINC 429) test jacks.
Look for signal activity.
WXP-840A/B
Data bus (453)
Connect scope to WXR DATA (ARINC 453)
test jacks.
Look for signal activity.
RTA-84X
WXP DATA
Connect scope to WXP DATA test jacks.
Look for signal activity.
WXP-840A/B
WXP CLOCK
Connect scope to WXP CLOCK test jacks.
Look for signal activity.
WXP-840A/B
28 April 1991
5-9
maintenance 523-0775827
Table 5-3. Fault Isolation Procedures at the WXP-840A/B.
STEP
PROCEDURE
DESIRED TEST RESULT
PROBABLE CAUSE OF
FAILED TEST
RANGE MARK
Connect scope to RANGE MARK test
jacks.
Look for signal activity.
WXP-840A/B
WXR BUSY
Connect scope to WXR BUSY test jacks.
Look for signal activity.
WXP-840A/B
WXR RETRACE
Connect scope to WXR RETRACE test
jacks.
Look for signal activity.
WXP-840A/B
WXR SHADOW
Connect scope to WXR SHADOW test
jacks.
Look for signal activity.
WXP-840A/B
WXR CONTROL
Connect scope to WXR CONTROL test
jacks.
Look for signal activity.
WXP-840A/B
Table 5-4. Fault Isolation Procedures at the RTA-84X.
STEP
Setup
PROCEDURE
DESIRED TEST RESULT
PROBABLE CAUSE OF
FAILED TEST
Turn off aircraft power to radar system.
Disconnect aircraft mating connect/cable from RTA-84X and connect test fixture (as shown in
Figure 5-3) between RTA-84X and aircraft wiring.
Be sure 28 V DC PWR ON/OFF switch on test set is set to OFF.
Set test fixture REMOTE ON/OFF/NORMAL switch to OFF.
Connect dvm between V/I+ and V- jacks.
Connect ammeter between V/I+ and I- jacks.
Turn on power to radar and EFIS systems.
Set 28 V DC PWR ON/OFF switch to ON.
Set WXP-840A?B MODE switch to STBY.
Set test fixture REMOTE ON switch to NORMAL.
Input voltage
Measure input voltage.
+27.5 V dc, ±5 V dc
A/C power supply
Input current
Measure input current (press PUSH I
switch).
3.5 A max, 3.0 A min
RTA-84X
Discretes
Data bus (429)
28 April 1991
Some of the TYPE
DISCRETES - WIRED indicators should light. Those
that do light indicate the
strapping options installed.
You may want to compare
the indication to the aircraft
documentation to verify
correct installation.
Connect scope to CONTROL DATA (ARINC
429 NO. 1) test jacks.
Look for signal activity.
WXP-840A/B (no. 1)
5-10
ADDENDUM 2
TO
MAINTENANCE SECTION (523-0775827)
Located in the
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
523-0775822-00111A, 1st Edition, dated 28 April 1991
Insert this addendum sheet between pages 5-10 and 5-11
At the next revision to this manual, paragraph 5.4 will be revised and expanded as follows:
5.4 ROUTINE AND PERIODIC MAINTENANCE PROCEDURES
There are no regular, routine, or periodic maintenance requirements for the Collins WXR-840 Advanced
Weather Radar System. However, it must be recognized that mechanically moving parts typically require
cleaning and lubrication. Therefore, it is suggested that whenever the system is inspected, tested, or repaired
for any other reason, the mechanical drive mechanism should be inspected to determine whether cleaning and
lubrication may be required. Furthermore, instances have been reported where physical damage to the radar
flat plate and/or mechanism has occured while the radar was exposed (radome removed). Therefore, users are
urged to be alert to the possibility of inadvertent damage during such procedures and ensure that the radar is in
good working condition when the radome is reinstalled and secured.
5.4.1 Cleaning and Lubrication of Scan and Tilt Mechanism
Inspect the mechanical portion of the RTA-84X, primarily the scan and the tilt gears and sectors, for
contaminants such as dirt and/or grease buildup. Unless the mechanism has been severely contaminated by
dirt and dried/baked lubricant, it should not be necessary to remove the unit for disassembly. In most cases, if
a small amount of contamination is present, adequate cleaning is possible using a small soft-bristled brush and
a lubricant based cleaning solution such as Genesolv 2004 or equivalent. After cleaning, apply a small amount
of grease, such as Aeroshell 7 or equivalent, to the gear and sector teeth. Wipe any excess grease from the
surrounding areas using a lint free cloth. Pay particular attention to the scan and tilt mechanism and note that
all mechanically mating parts are adequately lubricated. The scan and tilt motor bearings are lifetime lubricated
and therefore should not require re-lubrication.
5.4.2 Criteria for Antenna Flat Plate Inspection
Flightline Inspection:
At any service operation in which the radome is removed, ensure that the radar is in good physical condition
before the radome is reinstalled; that is, that no damage has been inflicted to the radar while the radome was
off. If such damage has occured, the radar should be removed and returned to a repair shop to determine the
extent of the damage and affect whatever repair is needed.
Shop Inspection:
At any service operation in which it is necessary to remove the radar assembly, antenna assembly, or the flat
plate, the flat plate should be carefully inspected for physical damage. The flat plate, or the flat plate drive
mechanism, should never be removed from the airplane for the single purpose of inspecting the flat plate for
damage unless it is clear that such damage has occured and removal is therefore necessary in order to
critically evaluate the extent of the damage.
Continued on reverse side:
Addendum 2
12 May 1995
523-0775827-022118
Sheet 3 of 4
(Facing page 5-11)
ADDENDUM 2
TO
MAINTENANCE SECTION (523-0775827)
Located in the
COLLINS WXR-840 ADVANCED WEATHER RADAR SYSTEM
INSTALLATION MANUAL
523-0775822-00111A, 1st Edition, dated 28 April 1991
This addendum is backing sheet 1 of Addendum 2
Continued from reverse side:
Criteria for shop inspection:
Any dent that deforms the plate surfaces; either front or back, septum sidewalls, or the main feed manifold
on the rear of the flat plate should be seen as cause for rejection or replacement. The septum should be
understood as referring to the spacers between the front and back surfaces of the flat plate.
A surface dent with an area less than 2-in2 and a depth of not more than 0.050 inch should be seen as
acceptable. A greater surface area or deeper dent should be seen as unacceptable.
Any dent or bending that occurs at the extreme edge of the antenna and outside the last waveguide wall,
can be ignored unless the weld is broken. Any broken weld that results in a separation between the
waveguide wall and the flat plate surface should be seen as unacceptable.
Any warping that results in a flat plate distortion of 0.0625 inch or more, with respect to the center of the
flat plate, should be seen as cause of flat plate rejection and replacement. In the case of convex distortion,
this can be detected by laying the flat plate on a flat bench surface, face down, with the center area of the
flat plate firmly in contact with the bench surface. If any point on the edge of the flat plate is off the surface
by 0.0625 inch or more, the warping should be judged unacceptable. For concave distortion, use a straight
edge ruler of sufficient length against the front surface of the flat plate and note that all points are within
0.0625 inch of the straight edge surface. Use several points in both the vertical and horizontal plane to
ensure that the plate is not twisted.
Note:
If and when windshear detection becomes operational and if these antennae are used in such an
application, the above criteria may not apply. In this case, damage inspection criteria may be
redefined.
Addendum 2
12 May 1995
523-0775827-022118
Sheet 4 of 4
(Backing Addendum 2, sheet 3)
maintenance 523-0775827
Table 5-4. Fault Isolation Procedures at the RTA-84X.
STEP
PROCEDURE
DESIRED TEST RESULT
PROBABLE CAUSE OF
FAILED TEST
In a dual WXP-840A/B installation only:
Data bus (429)
Connect scope to CONTROL DATA (ARINC
429 NO. 2) test jacks.
Look for signal activity.
WXP-840A/B (no. 2)
Data bus (453)
Connect scope to WXR DATA (ARINC 453)
test jacks.
Look for signal activity.
RTA-84X
TEST
Set WXP-840A/B MODE switch to TEST.
Antenna scans.
RTA-84X
STAB tests
Connect scope to STAB REF - IN test jacks.
Look for an ac signal (either
26 or 115 V ac).
Stabilization system
reference source
Connect scope to PITCH - IN test jacks.
Look for an ac signal.
Stabilization source
Input a pitch command from gyro source or
simulated source.
Look for antenna response:
antenna up for pitch-down,
antenna down for pitch-up.
RTA-84X
Input a roll command from gyro source or
simulated source.
Look for antenna response;
antenna pitch changes as it
scans from side to side.
RTA-84X
Complete
Remove test equipment and restore system to its normal operating configuration.
5.4 ROUTINE AND PERIODIC
MAINTENANCE PROCEDURES
5.5 IN-FLIGHT STABILIZATION
ALIGNMENT PROCEDURES
As part of each maintenance operation the mechanical portion of the RTA-84X, primarily the
scan and the tilt gears and sectors, should be
inspected for contaminants such as dirt and/or
grease buildup. Unless the mechanism has been
severely contaminated, it should not be necessary
to disassemble the unit for lubrication purpose.
In most cases if contaminants are present, adequate cleaning is possible using a small softbristled brush and lubricant-based cleaning solution. After cleaning to remove the contaminants,
apply a small amount of grease to the gear and
sector teeth. Wipe excess grease from the surrounding areas using a lint-free cloth. After
lubricating these parts, it is good practice to
operate the unit, paying particular attention to
the scan and tilt mechanism and noting that all
mechanically mating parts are lubricated adequately at the mating points. The scan and tilt
motor bearing are lifetime lubricated and should
not require re-lubrication. Table 5-5 is a listing
of the materials needed for this maintenance.
5.5.1 Introduction
28 April 1991
The stabilization alignment procedures are to be
performed in flight. The procedures calibrate the
WXR-840 system to the specific aircraft, and
especially to the vertical reference system, by
compensating for the remaining mounting errors.
The procedures utilize an alignment mode, built
into the RTA-84X, to introduce certain offsets
into the antenna roll and pitch attitude control
functions. These are stored in nonvolatile memory and, therefore, if done correctly, need to be
performed only once for a given installation.
In some installations, the stabilization alignment
feature may not be enabled. This procedure
cannot be performed unless a strap is connected
between WXP-840A/B rear connector pins J2-28
and J2-12.
The in-flight stabilization alignment procedures
are provided in paragraph 5.5.3 (Table 5-7) and
in paragraph 5.5.4 (Table 5-8). The first is a
more detailed version that can be used to gain
5-11
maintenance 523-0775827
Table 5-5. Materials and Tools Required for Routine/Periodic Maintenance.
ITEM
MANUFACTURE AND
PART NUMBER
DESCRIPTION
COLLINS
PART NUMBER
Oil
Lubrication oil
Cobehn Inc.,
Fairchild, N.J.
Univis P12, 04882
005-0392-000, 2-oz bottle
Freon
Fluorocarbon cleaning agent
E.I Du Pont de Nemours & Co., Inc.,
Freon Products Div,
Wilmington, Del.
Freon TMS, 73925
Not available
or:
Allied Chemical,
Allied Corp.,
Morristown, N.J.
Genesolv DMS, 70308
Grease
Lubricating grease
Shell Oil Co.,
Huston Tex.
Aeroshell 7
005-0810-000, 5-lb pail*
Brush
Soft bristled
Not available
Cloth
Lint-free cloth
Not available
*Contact manufacturer for lesser quantities.
familiarity with the process. For those experienced in the process, paragraph 5.5.4 is an abbreviated version that requires less reading during
the actual procedure.
5.5.2 Alignment Controls
All of the controls used for this procedure are on
the WXP-840A/B control panel. These are described in the following paragraphs.
parameters is selected by means of the MODE
switch, the selected parameter is annunciated in
place of TRIM. After one or more of the parameters have been satisfactorily adjusted and stored
in temporary memory by means of the HLD button (see below), pressing in on the recessed
button enters the parameters into permanent
nonvolatile memory.
b. MODE Switch
a. Stabilization Alignment Mode Activate Button
This is a recessed black pushbutton located at
the bottom center of the WXP-840A/B control.
Use this button to activate or end the stabilization alignment mode. Refer to Figure 3-1
in the operation section if necessary. Use a
small probe, similar to a ballpoint pen, to
press in on the button. Do not use a lead
pencil. Lead residue can cause damage to the
unit. When the stabilization alignment mode
is activated, TRIM is annunciated on the
EFIS display. When one of the adjustment
28 April 1991
The MODE switch is used to select the parameter to be adjusted, and the TILT control
is used to adjust that parameter. The switch
positions and the parameter thus selected are
summarized in Table 5-6.
c.
TILT Control Knob
The TILT control knob is used to adjust the
alignment parameter selected by means of the
MODE switch. The amount of adjustment
introduced becomes the electrical offset that
is used by the radar stabilization function.
5-12
maintenance 523-0775827
5.5.3 Detailed Alignment Procedures
d. HLD (Hold) Switch
The HLD switch is used to store the adjusted
value of the parameter into temporary radar
memory during the alignment process. There
are three adjustment parameters: roll offset,
pitch offset, and stabilization gain. Each of
these is adjusted separately and must be
entered into temporary memory before the
next parameter is selected.
The detailed alignment procedures are provided
in Table 5-7.
5.5.4 Abbreviated Alignment Procedures
The abbreviated alignment procedures are provided in Table 5-8.
Table 5-6. MODE Switch In-Flight Alignment Parameters.
MODE SWITCH POSITION
STABILIZATION ALIGNMENT MODE
WX
Selects roll offset for adjustment.
MAP
Selects pitch offset for adjustment.
TGT
Select stabilization gain for adjustment.
STBY
Discards any adjusted parameters, activates all alignment parameters stored in memory,
cancels alignment mode, and resumes normal operation.
TEST
Activates normal MAP mode to allow viewing of any radar target(s) using currently
adjusted alignment parameters not yet entered into memory.
OFF, then any mode
Regarding stabilization alignment, selecting OFF has the same effect as selecting STBY.
Pulling the primary power circuit breaker also has the same effect.
Table 5-7. Detailed In-Flight Stabilization Alignment Procedures.
STEP
NO.
PROCEDURE
DESIRED RESULT/DISPLAY
1.0
Before takeoff, be sure that stabilization alignment mode is enabled by a strap
between WXP-840A/B rear connector pins J2-28 and J2-12.
2.0
Before takeoff, position WXP-840A/B MODE switch to STBY and RANGE
switch to 50.
3.0
Complete all ground procedures for WXR-840 system installation and prepare
aircraft for flight.
Note
You may want to delay the following step until immediately before starting the alignment procedures (step 10.0).
This allows the full compass rose format to be used during takeoff and climbout.
4.0
For EFIS installations with an MFD, push PWR and RDR buttons.
For EFIS installations without an MFD, place ND in a sector format that
allows radar display.
5.0
After takeoff, select MAP mode.
6.0
Climb to normal cruise altitude and trim aircraft.
7.0
Wait about 5 minutes, with no roll or pitch changes, for attitude reference
system to stabilize.
8.0
If not already done, select MAP MODE. (Be sure GCS is not selected.)
28 April 1991
5-13
maintenance 523-0775827
Table 5-7. Detailed In-Flight Stabilization Alignment Procedures.
STEP
NO.
PROCEDURE
DESIRED RESULT/DISPLAY
9.0
Adjust TILT and RANGE. Depending on cruise altitude, select range that
gives best half-range ground clutter ring with least downward tilt.
10.0
If not already done in step 4.0:
Adjust so that near edge of
ground clutter ring is aligned
with EFIS half-range arc.
For EFIS installations with an MFD, push PWR and RDR buttons.
For EFIS installations without an MFD, place ND in a sector format that
allows radar display.
Note
In the following step you will activate the stabilization alignment mode by using a probe to depress the recessed
switch. Do not use a lead pencil. Lead residue can cause damage to the mechanical switches and can cause short
circuits.
11.0
Activate alignment mode by depressing recessed black button at bottom center
of WXP-840A/B control panel.
Note
During the course of this procedure, STBY can be used at any time to erase any adjusted parameters and return to
the value stored in permanent memory. For new installations, the stored values may be zero for all parameters.
12.0
Select WX MODE.
This selects roll offset for
adjustment.
13.0
Adjust TILT.
Adjust for best left/right symmetry of ground return display.
14.0
Press HLD momentarily to store adjusted value in temporary memory.
15.0
Select MAP MODE.
This selects pitch offset for
adjustment.
16.0
Adjust TILT.
Adjust so that near edge of
display is at a constant distance display arc.
17.0
Press HLD momentarily to store adjusted value in temporary memory.
18.0
Select TGT MODE.
19.0
Place aircraft into, and maintain, a shallow bank (5° to 10°, either left or
right).
This select stabilization gain
for adjustment.
Note
Prolong flight at a constant bank angle can cause precession in some gyro systems. Therefore, this attitude should not
be maintained for more than a few minutes. Additionally, after resuming straight and level flight, it is wise to wait a
few minutes for the gyro system to be corrected.
20.0
Adjust TILT.
21.0
Press HLD momentarily to store adjusted value in temporary memory.
28 April 1991
Adjust for best lest/right
symmetry of ground return
display.
5-14
maintenance 523-0775827
Table 5-7. Detailed In-Flight Stabilization Alignment Procedures.
STEP
NO.
PROCEDURE
22.0
At this point, select TGT MODE and any desired RANGE to view any radar
target display before storing adjusted parameters in permanent memory.
23.0
If, for any reason, you want to readjust a parameter, select MODE switch
position corresponding to desired parameter and readjust TILT as necessary.
Press HLD to store adjusted value in temporary memory.
24.0
If, for any reason, you want to restart procedure, select STBY to discard any
adjusted values and return to step 8.0.
25.0
If you are satisfied that the adjustments are the best that can be obtained,
press recessed button to store adjusted values in permanent memory and exit
stabilization alignment mode.
DESIRED RESULT/DISPLAY
Table 5-8. Abbreviated In-Flight Stabilization Alignment Procedures.
STEP
NO.
PROCEDURE
DESIRED RESULT/DISPLAY
1.0
After arriving at cruise altitude, trim aircraft for straight and level flight.
2.0
Select RANGE 50 and MAP MODE.
3.0
Adjust TILT.
Adjust for ground return at about
25 nmi.
4.0
Press recessed button.
This activates alignment mode
5.0
Select WX, adjust TILT, and press HLD to save.
Adjust for left/right symmetry of
display.
6.0
Select MAP, adjust TILT, and press HLD to save.
Adjust for uniform distance to
display edge.
7.0
Set up and maintain a constant aircraft bank altitude of about 5° to 10°.
8.0
Select TGT, adjust TILT, and press HLD to save.
9.0
Trim aircraft for straight and level flight.
10.0
Repeat as necessary:
a.
Adjust for left/right symmetry of
display.
Select STBY.
b. Go back to step 2.0.
or
Return to step 5.0, 6.0, or 7.0
11.0
Press recessed button.
28 April 1991
5-15
maintenance 523-0775827
WXP-840( )/850( ) Flight-Line Test Fixture, Panel Layout Diagram
Figure 5-1
28 April 1991
5-16
maintenance 523-0775827
Table 5-9. WXP-840( )/850( ) Flight-Line Test Fixture Parts List.
SYMBOL
DESCRIPTION
COLLINS PART NUMBER
Chassis, 4 x 6
504-1918-002
Cover, chassis, qty 2
504-1920-001
Indicator, lampholder/lens, red
262-2322-070
Bulb, 28 V
262-1883-020
Indicator, lampholder/lens, red
262-2322-070
Bulb, 28 V
262-1883-020
Indicator, lampholder/lens, red
262-2322-070
Bulb, 5 V
262-1883-000
DS4
LED, red
353-0293-040
DS5
LED, red
353-0293-040
DS6
LED, red
353-0293-040
R1
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R2
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R3
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
S1
Switch, spdt
266-5321-150
S2
Switch, pushbutton
260-2708-000
TP1-TP30
Choose from list below
DS1
DS2
DS3
Jack, tip, white
Jack, tip, red
Jack, tip, black
Jack, tip, brown
Jack, tip, green
Jack, tip, orange
Jack, tip, blue
Jack, tip, yellow
Jack, tip, violet
Jack, tip, gray
28 April 1991
360-0149-000
360-0150-000
360-0151-000
360-0152-000
360-0153-000
360-0154-000
360-0155-000
360-0156-000
360-0157-000
360-0158-000
5-17
maintenance 523-0775827
WXP-840( )/850( ) Flight-Line Test Fixture, Schematic Diagram
Figure 5-2 (Sheet 1 of 2)
28 April 1991
5-18
maintenance 523-0775827
WXP-840( )/850( ) Flight-Line Test Fixture, Schematic Diagram
Figure 5-2 (Sheet 2)
28 April 1991
5-19
maintenance 523-0775827
RTA Flight-Line Test Fixture, Panel Layout Diagram
Figure 5-3
28 April 1991
5-20
maintenance 523-0775827
Table 5-10. RTA Flight-Line Test Fixture Parts List.
SYMBOL
DESCRIPTION
COLLINS PART NUMBER
Chassis, 4 x 6
504-1918-002
Cover, chassis, qty 2
504-1920-001
Indicator, lampholder/lens, red
262-2322-070
Bulb, 28 V
262-1883-002
DS2
LED, red
353-0293-040
DS3
LED, red
353-0293-040
DS4
LED, red
353-0293-040
DS5
LED, red
353-0293-040
DS6
LED, red
353-0293-040
DS7
LED, red
353-0293-040
DS8
LED, red
353-0293-040
DS9
LED, red
353-0293-040
DS10
LED, red
353-0293-040
R1
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R2
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R3
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R4
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R5
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R6
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R7
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R8
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R9
Resistor, cc, 2.7 kΩ, 10%, 1/4W
745-0764-000
R10
Resistor, cc, 10 kΩ, 10%, 1/4W
745-0785-000
S1
Switch, spdt
266-5321-150
S2
Switch, pushbutton
260-2708-000
S3
Switch, dpdt
266-5321-200
S4
Switch, dpdt
266-5321-200
S5
Switch, dpdt
266-5321-200
S6
Switch, dpdt
266-5321-200
DS1
TP1-TP24
Choose from list below
Jack, tip, white
Jack, tip, red
Jack, tip, black
Jack, tip, brown
Jack, tip, green
Jack, tip, orange
Jack, tip, blue
Jack, tip, yellow
Jack, tip, violet
Jack, tip, gray
28 April 1991
360-0149-000
360-0150-000
360-0151-000
360-0152-000
360-0153-000
360-0154-000
360-0155-000
360-0156-000
360-0157-000
360-0158-000
5-21
maintenance 523-0775827
RTA Flight-Line Test Fixture, Schematic Diagram
Figure 5-4 (Sheet 1 of 2)
28 April 1991
5-22
maintenance 523-0775827
RTA Flight-Line Test Fixture, Schematic Diagram
Figure 5-4 (Sheet 2)
28 April 1991
5-23/(5-24 blank)