Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Chapter 27
Flight Controls
Page Date: 8. December 1999
27
Page 1
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
TABLE OF CONTENTS
27-00-00
GENERAL .........................................................................................................4
Description ..........................................................................................................4
27-00-01
Cable Tensions ...................................................................................................4
27-01-00
CONTROL SPRINGS.......................................................................................6
Location...............................................................................................................6
27-01-01
Down-Spring ......................................................................................................6
Description ..........................................................................................................6
27-01-02
Interconnection Aileron / Rudder....................................................................6
Description ..........................................................................................................6
27-01-03
Centering Rudder..............................................................................................7
Description ..........................................................................................................7
27-01-04
Nose Gear Steering ............................................................................................7
Description ..........................................................................................................7
27-01-05
Nose Gear Control Cable ..................................................................................7
Description ..........................................................................................................7
27-10-00
AILERONS ........................................................................................................8
Description ..........................................................................................................8
Troubleshooting...................................................................................................9
Removal / Installation........................................................................................10
27-10-01
Aileron Cables..................................................................................................11
Removal / Installation........................................................................................11
27-20-00
RUDDER ..........................................................................................................12
Description ........................................................................................................12
Troubleshooting.................................................................................................13
Removal / Installation........................................................................................14
27-20-01
Rudder Cables .................................................................................................15
Removal / Installation........................................................................................15
Page 2
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Page Date: 27. September 2000
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-30-00
ELEVATOR AND TAB ................................................................................. 16
Description........................................................................................................ 16
Troubleshooting ................................................................................................ 17
Elevator Control System ................................................................................... 17
Elevator Trim Tab Control System ................................................................... 18
Removal / Installation....................................................................................... 19
27-30-01
Elevator Cables ............................................................................................... 20
Removal / Installation....................................................................................... 20
27-50-00
FLAP SYSTEM ............................................................................................... 21
Description........................................................................................................ 21
27-51-00
FLAP DRIVE SYSTEM ................................................................................. 22
Description........................................................................................................ 22
27-51-01
Drive Unit......................................................................................................... 22
27-51-02
Power Transmission........................................................................................ 22
27-52-00
FLAP CONTROL SYSTEM ......................................................................... 24
Description........................................................................................................ 24
27-53-00
RIGGING AND ADJUSTMENT FLAP SYS TEM ..................................... 25
27-53-01
Flap Track Adjustment .................................................................................. 25
27-53-02
Flap Guidance Checks and Adjustment ....................................................... 25
27-53-03
Flap Actuation Adjustment............................................................................ 26
27-53-04
Adjustment of Flap Limit Switches............................................................... 28
27-53-05
Flap Asymmetry Senders ............................................................................... 30
Adjustment ........................................................................................................ 30
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-00-00
GENERAL
Description
The flight controls consist of the ailerons, rudder and elevators. The right
elevator is equipped with a trim system. All these control surfaces are
constructed of composite material. The primary control system is a
conventional cable-system consisting of a double control wheel (pitch and roll)
with respective coupling systems, hanging control pedals (yaw), tubes, levers,
pulleys and push-pull rods. Between ailerons and rudder controls an
interconnection which is made via springs is installed. However, the coupling
can easily be overpowered (e.g. in side slipping).
27-00-01
Cable Tensions
The control cable systems generally use cable of 3.2 mm diameter. However
the aileron control uses cables of 4 mm diameter in the wing region.
Page 4
27
System
Cable Diameter
Cable Tension
Tolerance
Ailerons
3.2 mm / 4 mm
220 N / 49.5 lbs
± 20 N / 4.5 lbs
Rudder
3.2 mm
220 N / 49.5 lbs
± 20 N / 4.5 lbs
Elevator
3.2 mm
300 N / 67.4 lbs
± 20 N / 4.5 lbs
Page Date: 27. September 2000
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
Figure 27-01
System Surview
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-01-00
CONTROL SPRINGS
Location
The following springs are incorporated in the control system of the EA-400:
Application
27-01-01
Location
Down-spring
Cockpit, instrument shelf
Interconnection aileron / rudder
Cockpit, bulkhead
Centering rudder
Tailcone fairing
Nose gear steering
Nose wheel dome
Nose gear control cable
Cockpit
Down-Spring
Description
Safety spring, affecting the pulley segment of the elevator control, to create a
nose-down pitching control force. The down-spring is located on the LH side,
below the instrument shelf.
In case of down-spring failure the amount of steering force required will rise
when pushing the control yoke. Trimming "nose down" will compensate this
effect. Malfunction of the down-spring will not cause further reductions of
flight performance or any unsafe flight conditions.
27-01-02
Interconnection Aileron / Rudder
Description
To reduce tendency to raise the low wing, esp. during low speed flight (landing
approach), the EA-400 is furnished with an interconnection between the aileron
and the rudder control. When activating the rudder, the coupling
correspondingly actuates the aileron control. When moving the aileron, the
rudder — as long as being free of any control forces — remains in ne utral
position.
The coupling is being accomplished by means of a pair of safety springs,
located at the LH foot compartment. The control force is conducted from the
shafts of the rudder control to the safety springs by levers and cables, including
the pulleys.
Once the friction inside the control system has been overcome, a rudder control
input is led to the LH control column by a chain drive.
Failure of an interconnection spring will cause an additional force in one
direction at the aileron control, which is rated below the tolerated amount.
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-01-03
Centering Rudder
Description
Within the lower rudder bearing a spring- loaded pulley strains a steel plate
attached to the rudder, thus centering the rudder in neutral position and
providing a defined rising of control forces while moving the rudder.
Malfunction of the centering spring will disengage the centering and reduce the
control force rise. Unsafe flight conditions are excluded.
27-01-04
Nose Gear Steering
Description
The pivoting of the nose gear is part of the rudder control system, completing
the control cable arrangement. To de-couple the nose gear steering from the
rudder control, two safety springs are incorporated into the nose gear pivoting.
The springs will transmit the control force forward after having reached a
defined travel.
Malfunction of the nose gear steering springs will abolish pretension of the
control cables. With a 16° play arising inside the nose gear steering, reduction
of max. angular movement from ± 30° to approx. 10° in one direction will
occur, whereas control force at the rudder pedals will slightly increase.
27-01-05
Nose Gear Control Cable
Description
These additional springs will stretch the nose gear control cables, when one of
the springs at the nose gear pivoting has been lengthened due to a rudder
movement against the locked nose wheel.
Malfunction of one or both springs will not affect normal control functions.
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-10-00
AILERONS
Description
The coupling between the two control wheels of the main control system is
realized by a direct cable-chain coupling. The cables are connected to the
control wheels by means of a longitudinal toothed wheel and run through the
windshield center strut to the wing nose and move outboard. Outside the tank
area they cross the front spar. Then they are connected to a cable segment
which actuates the aileron via lever and push-rod.
Each aileron is attached to the rear spar of the wing by two hinges.
Page 8
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Page Date: 27. September 2000
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
Troubleshooting
Complaint
Lost motion in control wheel.
Resistance to control wheel
movement.
Control wheels not level with
ailerons neutral
Possible Cause
Remedy
Loose control cables.
Check cable tension. Adjust
cables to proper tension.
Broken pulley or braket, cable
of pulley or worn rod end
bearings.
Check visually. Replace worn
or broken parts, install cables
correctly.
Cables too tight.
Check cable tension. Adjust
cables to proper tension.
Pulleys binding or cable off.
Observe motion of the pulleys.
Check cables visually. Replace
defective pulleys. Install
cables correctly.
Defective quadrant assembly.
Check visua lly. Replace
defective quadrant.
Clevis bolts in system too
tight.
Check connections where
used. Loosen, then tighten
properly and safety.
Improper adjustment of cables. Adjust turnbuckle to obtain
proper alignment.
Improper adjustment of
aileron push-pull rods.
Adjust push-pull rods to obtain
proper alignment.
Dual control wheels not
coordinated.
Cables improperly adjusted.
Refer to paragraph XX.
Chain improperly adjusted.
Refer to paragraph XX.
Incorrect aileron travel.
Push-pull rod not adjusted
properly.
Refer to paragraph XX.
Incorrect adjustment of travel
stop bolts.
Refer to paragraph XX.
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
Removal / Installation
Detail Steps/Work Items
Key Items
Removal
1 Loosen push rod from central part of aileron
2 Remove cotter pin and bolt from each of the
two hinges
3 Remove aileron backwards
Installation
Install in reverse order of removal
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Page Date: 27. September 2000
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-10-01
Aileron Cables
Removal / Installation
Detail Steps/Work Items
Key Items
Removal
1 Remove center cover of wing root section
2 Remove turnbuckle below cover
Perform steps No 3 – 9 at LH and RH side wing each
3 Remove turnbuckle at outer wing rib
4 Remove rigging clamps of role servo at
inner wing rib
5 Remove recognition light at outer wing nose
section
6 Remove outer side pulley
7 Push up inner side pulley
8 Remove teflon guiding bushings at outer
wing rib
9 Loosen return cable segment at outer wing
rib for removal of 3.6 mm cable
Remove bolt and push
segment sideways
10 Remove 2 pulleys at windshield center strut
11 Remove teflon guiding bushings at
windshield center strut
12 Remove avionic panel
13 Remove LH and RH side return brackets
14 Remove LH and RH cable safety brackets
below instrument shelf
15 Loosen return cable segments at steering
column
Remove bolts and push
segments sideways
Installation
Install in reverse order of removal
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-20-00
RUDDER
Description
The rudder pedals are placed hanging on two tubes which have a lever arm at
the right side of the cabin. From there the cables are led along the cabin right
side armrest panel to the empennage around pulleys positioned in groups. Here
a direct connection to the lever arms of the rudder follows. The connection
points lay inside the tail cone adjacent to the lower rudder bearing.
The rudder is connected to the rear fin spar at three points.
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Page Date: 27. September 2000
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
Troubleshooting
Complaint
Possible Cause
Remedy
Rudder does not respond to
pedal movement.
Broken or disconnected
cables.
Open armrest panel, access
plates and check visually.
Connect or replace cables.
Binding or jumpy movement
of rudder pedals.
Cables too tight.
Rig the system in accordance
with paragraph XX.
Cables not riding properly on
pulleys.
Open armrest panel, access
plates and check visually.
Route cables correctly over
pulleys.
Binding, broken or defective
pulleys or cable guards.
Open armrest panal, access
plates and check visually.
Replace defective pulleys and
install guards properly.
Pedal bears need lubrication.
Lubricate pedal bears.
Defective rudder bar bearings.
If lubricate fails to eleminate
binding. Replace bearing
blocks.
Defective rudder hinge
bushings.
Check visually. Replace
defective bushings.
Clevis bolts too thight.
Check and readjust bolts to
eleminate binding.
Steering rods improperly
adjusted.
Rig the system in accordance
with paragraph XX.
Lost motion between rudder
pedals and rudder.
Insufficient cable tension.
Rig the system in accordance
with paragraph XX.
Incorrect rudder travel.
Incorrect rigging.
Rig in accordance XX.
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
Removal / Installation
Detail Steps/Work Items
Key Items
Removal
1 Remove right aft seat
Refer to Ch 25-21-02
2 Remove RH side panelling
3 Loosen two turnbuckles of rudder cables,
located at RH wall adjacent to right aft seat
and baggage compartment
4 Loosen rudder cables at lower rudder
bearing
5 Remove bolt at LH side of central rudder
bearing
6 Remove lower rudder bearing
5 screws M5
7 Remove cotter pin and nut at lower rudder
bearing
8 Slightly lift rudder above higher bearing and
remove rudder backwards
Installation
Install in reverse order of removal
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Page Date: 27. September 2000
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-20-01
Rudder Cables
Removal / Installation
Detail Steps/Work Items
Key Items
Removal
1 Remove lower RH side panels in flight,
passenger and baggage compartments
2 Remove upper rear wall of baggage
compartment
3 Remove instrument shelf
4 Remove turnbuckle below RH side of
instrument shelf
5 Remove 2 turnbuckles at RH side wall in
baggage compartment
6 Remove turnbuckle at rear wall of baggage
compartment
7 Remove 2 pulleys below instrument shelf
Remove safety pin from
smaller pulley
8 Remove 2 pulleys from RH side wall in
flight compartment
Remove bolts
9 Remove 2 pulleys from RH side wall in rear
passenger compartment
Remove bolts
10 Remove teflon guiding bushings at rear wall
of baggage compartment
11 Remove LH access panel at rear fin
12 Remove 2 smaller pulleys
13 Remove 2 pulleys at LH and RH side each
below instrument shelf
14 Remove teflon guiding bushings to nose
wheel well
Remove safety sheet
15 Remove nose gear cable control springs
Installation
Install in reverse order of removal
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-30-00
ELEVATOR AND TAB
Description
A lever system transfers elevator control movement from each of the two
steering wheels by a respective carrier bolt bushing to a cable segment. From
this cable segment the elevator cables run horizontally to the right cabin side to
a 90° pulley and parallel to the rudder cables to the empennage. They are led to
the elevator in front of the front fin spar and are attached to a lever positioned
in front of the horizontal stabilizer front spar, which actuates the two elevator
sides separately by means of push pull rods. Each elevator is attached to the
respective horizontal stabilizer by three bearings.
The mechanic al pitch trim is actuated through a trim wheel in the pedestal. The
pitch trim tab is located in the right elevator and is linked over a 'redundant'
cable- lever system to the trim wheel. The trim bowden cables run from the
middle console down crossing the cabin floor and are then directed rearwards
to the empennage following the nose section of the fin to the right side
elevator. Pitch trim can be actuated electrically also by means of switches
located on the pilot's control wheel. The system can be overpowered by pilot's
hand forces in case of system failure.
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Page Date: 27. September 2000
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
Troubleshooting
Elevator Control System
Complaint
Lost motion in control wheel.
Possible Cause
Remedy
Loose control cables.
Check cable tension. Adjust
cables to proper tension.
Broken pulley or bracket,
cable of pulley or worn rod
end bearings.
Check visually. Replace worn
or broken parts, install cables
correctly.
Cables too tight.
Check cable tension. Adjust
cables to proper tension.
Pulleys binding or cable off.
Observe motion of the
pulleyes. Check cables
visually. Replace defective
pulleys. Install cables
correctly.
Defective quadrant assembly.
Check visually. Replace
defective quadrant.
Clevis bolts in system too
tight.
Check connections where
used. Loosen, then tighten
properly and safety.
No nose down force on control
wheel.
Down-spring disconnected.
Check visually. Attach
down-spring correctly.
Binding or jumpy motion felt
in movement of elevator
system.
Cables slack.
Check and adjust to tens ion
specified in paragraph XX.
Cables not riding correctly on
pulleys.
Check visually. Replace
defective rollers.
Defective control column
bearing rollers.
Check visually. Replace
defective rollers.
Defective control column
torque tube bearings.
Disconnect necessary items
and check that bearings rotate
freely. Replace defective
bearing.
Control guide on aft end of
control square tube adjusted
too tightly.
Loosen screwand tapered
plugin end of control tube
enough to eliminate binding.
Defective elevator hinges.
Disconnect push-pull tube and
move elevators by hand.
Replace defective hinges.
Resistance to control wheel
movement.
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
Complaint
Elevators fail to attain
prescribed travel.
Possible Cause
Remedy
Stops incorrectly set.
Rig in accordance with
paragraph XX.
Cables tightened unevenly.
Rig in accordance with
paragraph XX.
Interference at instrument
panel.
Rig in accordance with
paragraph XX.
Elevator Trim Tab Control System
Complaint
Trim control wheel moves
with excessive resistance.
Lost motion between control
wheel and trim tab.
False reading on trim position
indicator.
Incorrect trim tab travel.
Page 18
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Possible Cause
Remedy
Defective cable or tube.
Check visually and replace
defective parts.
Trim tab hinge binding.
Disconnect actuator and move
tab up and down to check
hinge resistance. Lubricate or
replace hinge as necessary.
Defective trim tab actuator.
Disconnect cable from
actuator and operate actuator
manually. Replace defective
actuator.
Stick-slip effect between cable
and tube.
Lubricate all moving parts.
Disconnected or broken cable.
Check visually and connect or
replace cable as necessary.
Unacceptable free play.
Reduce free play in
accordance with paragraph
XX.
Indicator incorrectly engaged
on wheel track.
Check visually. Adjust
indicator.
Worn, bent or disconnected
linkage.
Check visually. Repair or
replace parts as necessary.
Stop blocks loose or
incorrectly adjusted.
Adjust stop blocks on cables.
Incorrect rigging.
Refer to paragraph XX.
Page Date: 27. September 2000
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
Removal / Installation
Detail Steps/Work Items
Key Items
Removal
RH elevator
1 Loosen push rod at trimming tab
8 hollow core bolts LN4
2 Continue as per step 1 to 5, LH elevator
LH elevator
1 Loosen control lever
2 Swivel up elevator
3 Remove socket pins from central and outer
bearings
2 socket pins LN6
4 Turn elevator horizontally backwards
around inner bearing
5 Remove elevator
Installation
Install in reverse order of removal
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-30-01
Elevator Cables
Removal / Installation
Detail Steps/Work Items
Key Items
Removal
1 Remove lower RH side panels in flight,
passenger and baggage compartments
2 Remove upper rear wall of baggage
compartment
3 Remove instrument shelf
4 Remove turnbuckle below RH side of
instrument shelf
5 Remove 2 turnbuckles at RH side wall in
baggage compartment
6 Remove turnbuckle at rear wall of baggage
compartment
7 Remove 2 pulleys below instrument shelf
Remove safety pin from
smaller pulley
8 Remove 2 pulleys from RH side wall in
flight compartment
Remove bolts
9 Remove 2 pulleys from RH side wall in rear
passenger compartment
Remove bolts
10 Remove teflon guiding bushings at rear wall
of baggage compartment
11 Remove LH tailcone access panel
12 Remove 2 clamps of pitch servo
13 Remove LH access panel at rear fin
14 Remove 2 larger pulleys
15 Remove linkage between cable and aileron
Remove bolt
16 Remove push rod
Installation
Install in reverse order of removal
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-50-00
FLAP SYSTEM
Description
The wing flaps are of the Fowler type. Each wing flap (two per side) is
attached to the rear wing spar and guided during its movement by three wing
tracks. Actuation is by means of two spindles, which are connected to the
central electrical flap motor by flexible shafts. The flap motor is located in
front of the rear spar in the fuselage area of the wing and is controlled by the
wing flap position switch in the cockpit. This switch incorporates a preselect
feature which allows the pilot to select the amount of flap extension desired.
When the UP/0°- , 15°- or 30°- position is selected, the flap motor is
electrically actuated and drives the flaps toward the selected position. When the
actual flap position equals the selected position, limit switches located at the
wing tracks respective the outer spindles de-energize the flap motor. The actual
flap position will be indicated by green lights at the left side of the wing flap
position switch. When flaps are moving the yellow light will be illuminated. If
the 0°-position is reached all lights are off.
As the flaps move an electrical circuit compares the movement of the left and
right wing flaps. If the wing flap positions differ by more than 7° ± 3°, the flap
motor will be automatically switched off to prevent asymmetric conditions.
This will be indicated by the flap error warning light located on the warning
light panel. This light indicates also a failure of the complete flap control.
NOTE
In case of the wing flaps being unbalanced, they rest in the position they
have reached when failing and cannot be actuated until airplane has been
in maintenance. However in this case the airplane can be easily balanced
by slight aileron and/or rudder input.
Setting the wing flaps will cause a decrease of airspeed and a moderate nose
down moment.
CAUTION
Bring wing flaps to 0°-position before opening the cabin door
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-51-00
FLAP DRIVE SYSTEM
Description
27-51-01
Drive Unit
Electrical Motor
Brush type bidirectional permanent magnet motor (Engel GNM 4175 mod),
positioned in the wing center box at the front web of the rear spar
Characteristics:
1 Hex shafts on both sides
2 Capability of dynamic braking
3 Max. ambient temperature: + 40 °C
4 Voltage: 24 to 30 VDC, 24 VDC nominal
5 Torque at output shaft: 50.7 Ncm nominal at 24 VDC, 1,600 RPM, 4.5 amps
6 Power output: 85 W
7 Ratio RPM / Torque: 5.1 (Ncm ⋅ min) -1
8 Voltage factor: 0.013 V ⋅ min
9 Efficiency: 78 %
10 Insulation class IP 54 according DIN 40050 (protected against dirt, dust and
ingressed water)
27-51-02
Power Transmission
Flexible Shafts Inboard
The inboard flex shaft has a female 3/16" hex drive at motor side and a DIN
75532 E1 for the screw jack side. LH and RH flex shaft are different in main
rotation due to the musk wire: CW or CCW for main rotation.
Characteristics:
1 Length: 1,400 mm
2 Core: Carbon steel musk wire φ 6 mm
3 Casing and end fittings in CRES
4 Shrink sleeve on casing
5 Minimum installation bend radius: 300 mm
6 Coupling nut 2024-T4 blue anodized or CRES with hole for safety wire
7 Min. static torque : 300 Ncm
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
Flexible Shafts Outboard
The outboard flex shaft is a standard type DIN 75532 E1. As for the inboard
shaft LH and RH flex shafts are different in main rotation due to the musk
wire: CW or CCW for main rotation.
Characteristics:
1 Length: 2,000 mm
2 Core: Carbon steel musk wire φ 4 mm
3 Steel casing
4 End fitting in steel zinc - plated galvanically
5 Shrink sleeve on casing
6 Minimum installation bend radius: 55 mm
7 Coupling nut aluminium with hole for safety wire
8 Min. static torque: RH 104 Ncm (CCW) / 49 Ncm (CW)
LH 104 Ncm (CW) / 49 Ncm (CCW)
Screw Jack Inboard & Outboard
The screw jack consists of a reduction worm gear and machine screw nut with
trapezoid thread (irreversible by choice of pitch). The worm shaft and the
screw nut are equipped with all bearings.
Characteristics:
1 Worm gear ratio: inboard 5:1
outboard 7:1
2 Efficiency of worm gear: inboard 0.7
outboard 0.65
3 Pitch of screw nut: 3 mm stroke per revolution
4 Number of revolutions for full stroke of screw jack (30° flap setting):
inboard 70 revolutions
outboard 50 revolutions
5 Stopping accuracy: ± 3 % of full stroke
6 The unit is sealed
7 All external parts are protected against corrosion
8 Periodic lubrication is not required
9 Output shaft splines: According DIN 75532 E2 for connection to the flexible
drive shafts
Page Date: 27. September 2000
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-52-00
FLAP CONTROL SYSTEM
Description
The two electrical units providing the flap control functions are located in the
fuselage area of the wing, in front of the rear spar.
The Flap Control Box (Becker FCB 400-1) performs the following functions:
1 Controlling the motor for the 3 intended flap - positions (retracted, 15° intermediate and 30° fully extended)
2 Activating the flap position signals 15°, 30° or "flaps in transition"
The Watchdog (Becker FZB 400-1) performs the following functions:
Asymmetry detection by controlling the rheostats fitted at the outboard flaps
on the LH and RH, thus activating:
1 Motor shut-off
2 Signalisation to the warning panel inside the cockpit
Wing flap asymmetric tolerances are adjustable at the trimmer of the watchdog
box. Refer to Ch. 27-53-05.
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Page Date: 27. September 2000
Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-53-00
RIGGING AND ADJUSTMENT FLAP SYSTEM
This section describes the procedure for correct adjustment of the defined flap
settings as well as the maximum flap asymmetric limits.
Due to the local chord of the flaps (30 % of the wing) and positioning the 15°
and 30° DOWN extension relative to the local chord the travel of the flaps
depends on the lateral station.
CAUTION
All adjustment must be made with the motor power OFF (pulled circuit
breaker FLAP).
NOTE
Rigging of the flap system requires a flap track snap gauge (Extra PartNo. EA-15182W10). This will be available at Extra Flugzeugbau GmbH.
Drawing see also Chapt. 05-00-01.
27-53-01
Flap Track Adjustment
Perform the following adjustment checks as long as the flaps are not installed.
For flap installation, refer to Ch . 57-50-01.
1 Check of spanwise adjustment
Check distance between flap tracks at their rear end. Distance between inner
and middle track is 1989 ± 2 mm (78.31 ± 0.08 in.) and between middle and
outer track 1827.5 ± 2 mm (71.95 ± 0.08 in.). If further details of flap track
positioning are required, contact Extra Flugzeugbau GmbH.
2 Check of twist between tracks
Check flap tracks for proper torsional alignment (cord over all three lower
keyways). Max. permissible distance of lower keyway centerline at the middle
flap track is 2mm (0.08 in.), when cord is aligned with outer and inner flap
track keyway.
27-53-02
Flap Guidance Checks and Adjustment
Check the following items after flap installation:
1 Minimum gap between flap and aileron
While pulling the flaps outboard against the stop, check width of gap between
aileron and outer flap segment. The stop is reached, when one of the sliding
surfaces on the outboard end of the inner or outer flap segment contacts the
middle or outer flap track. Minimum gap width is 8 mm (0.31 in.).
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September
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Maintenance Manual and Illustrated Parts Catalogue
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Flight Controls
Check the following items after flap installation and after each 100 hours of
operation:
2 Spanwise flap rigging
Check whether any guidance roller on the inner track protrudes more than
3 mm (0.12 in.) outside the inner track when flaps are pulled outboard against
the stop. The stop is reached, when one of the sliding surfaces on the outboard
end of the inner or outer flap segment contacts the middle or outer flap track.
Repeat the check for the rollers in the outer flap track while pushing the flaps
inboard. Verify visually that stops are definitely reached.
3 Flap guidance rollers twist rigging
Minimum play in guidance keyways: Check all flap segments fo r minimum
free play of rollers in keyways. Lift each flap segment manually at trailing edge
and observe for positive free play of flap segment at trailing edge. Check this
for all four flap segments and for flap positions 0° and 30°. The SKF track
rollers (forward roller on inner track and both rollers on outer track) feature an
eccentric bushing to provide a means of adjustment in this respect.
4 Flap guidance rollers functional check
Check whether the rollers are rolling but not slipping by performing the
following test: Extend flaps to their 30° position and retract them while
manually applying a load of about 200 N (45.0 lbs.) upwards at the trailing
edge of the flaps near the respective track. If a roller is slipping identify cause
and replace roller as necessary.
5 Inspection of roller contact areas
Inspect rear side of lower keyway on inner flap tracks for signs of axial contact
with mushroom head of roller. Contact Extra Flugzeugbau GmbH if marks are
found.
Inspect guidance roller tracks for wear and permanent deformation.
For wear and deformation the following service limits are defined:
Max. increase of track width due to deformation: 0.6 mm (0.024 in.) per side.
Width of guidance slot between 16.3 mm and 16.8 mm (0.64 in. and 0.66 in.).
Check with flap track snap gauge (see Chapt. 05-00-01).
27-53-03
Flap Actuation Adjustment
1 Ascertain that both inner flex drive shafts are disconnected from the electric
drive motor and that the flap motor and flap control circuit breakers are pulled.
2 Make sure for both LH and RH side flap that the respective asymmetry
detection mechanisms are not mounted yet. If they are already mounted, make
sure that the ball joint connection between linkage rod and bracket is
disconnected and the linkage rod is taped to the spar.
CAUTION
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If this is not done, parts of the mechanism may be destroyed while
moving the flaps.
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Maintenance Manual and Illustrated Parts Catalogue
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3 Lower both (LH and RH) flaps to their fully extended stop position. This can
be done by turning the hex socket coupling of the RH flex shaft CCW and the
LH flex shaft CW respectively, with view of the coupling. Use a battery hand
held drill with fine speed control and reverse feature, equipped with a 3/16 “
(4.7 mm) Allen key tip.
CAUTION
Do not run flaps to their extreme position (end of trackslots) with electric
drill to avoid damage. Turn flex shafts by hand to reach the end of the
tracks.
4 If the roller on one flap end rib reaches the outer end of its track slot while the
roller on the other flap end rib is 2 mm or more away from its track slot end,
an adjustment is necessary. This is done at one of the two transmission screw
jacks.
5 Disconnect the flap bracket from the rod end of its transmission actuator, then
move the rod into the proper direction by rotating it in steps of 180°-turns,
then reconnect. A 180°-turn of the inner transmission’s rod in CCW direction
or of the outer transmission’s rod in CW direction will move the adjacent
roller about 2 mm towards the extended position.
NOTE
The screw of the inboard transmission rod features a RH thread whereas
the outboard one features a LH thread
6 Raise both (LH and RH) flaps from their extended stop positions by rotating
the hex socket coupling of the flex drive shafts 2.5 turns in reverse direction to
secure a gap between rollers and track slot ends about 1.5 mm (.06"). This will
give the 30° position. Use a 3/16" (4.7 mm) Allen key and turn by hand.
7 The basic adjustment dimensions at the transmission actuators (measured from
the center of the mounting pin of the screw jack to the center of the rod end)
are:
Position
Inner actuator
Outer actuator
0° Retracted
15° Intermediate
30° Extended
58 + 3 / - 0 mm
152 + 3 / - 0 mm
270 + 3 / - 0 mm
2.28 + .12/-0 inches
5.98 + .12/-0 inches
10.63+ .12/-0 inches
68 + 3 / - 0 mm
135 + 3 / - 0 mm
219 + 3 / - 0 mm
2.68 + .12/-0 inches
5.31 + .12/-0 inches
8.62 + .12/-0 inches
8 If the rod end at the transmission screw and the respective flap bracket do not
align, disconnect the rod end from the bracket and loosen the two bolts
securing the bracket to the flap. This will allow the bracket to be moved by
tapping. Connect the rod end to the bracket and tap the bracket to achieve a
satisfactory alignment. Disconnect the rod end from the bracket and torque the
bracket attachment bolts. With the transmission screw and flap bracket
aligned, finally connect the rod end to the bracket with the bolt assy.
9 When measuring flap deflection angles, lift the trailing edge of the flap to
eliminate play between rollers and track slots.
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-53-04
Adjustment of Flap Limit Switches
The 0° and 30° flap positions are detected by four limit switches, every two of
them attached to a mounting bracket positioned on the LH and RH side wing’s
rear spar web. If one DOWN or UP limit switch related to any of these flap
positions fails, the remaining one on the opposite side will still detect the
desired flap position.
The extended flap position is detected by the DOWN limit switch on the LH
flap (backup switch on the RH side) and the retracted flap position is detected
by the UP limit switch on the RH flap (backup switch on the LH side).
The switches are operated by the same linkage mechanism that is used for
asymmetry detection.
The 15° flap position is detected by two limit switches at the LH outboard
screw jack.
DOWN Limit Switch
1 Run the flaps to the 30° position determined before. If not present yet, mount
both asymmetry detection potentiometers and put the lever arm on the
potentio meter shafts, but do not tighten their clamping screws yet.
CAUTION
Tightening of the clamping screws may destroy parts of the mechanism
while moving the flaps.
2 At the LH side wing flap, determine the axial and the angular position of the
arm on the potentiometer shaft so that it contacts the 30° limit switch in the
center of the arm.
3 With the positions of the potentiometer arm and flap bracket given, adjust the
linkage rod until it fits. The start value is 66 mm (2.6”) between the ball joint
centers. The length adjustment is done by loosening the nuts and rotating the
rod, which features one LH side and one RH side thread. Tighten the rod nuts
and the ball joint nuts after the adjustment is completed, but do not tighten the
potentiometer arm clamping screw.
4 Manually move the flaps up to the retracted position as described in Chapter
27-53-02, step 3. With the flaps on retracted position the gap between the flap
and the wing, measured at the lower side, should be 4 mm (.16”).
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Maintenance Manual and Illustrated Parts Catalogue
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UP Limit Switch
1 Perform the same way as with the DOWN limit switch, but with the rod
linkage of the RH flap accordingly. Stop the flaps in retracted position just
before any of the flap rollers reach the end of the track slots (approximately
1.5 mm (.06") space should remain between the end of the track slot and the
closer roller of both flaps). Ascertain at least 1.5 mm (.06") clearance between the tip of the potentiometer arm and the spar.
NOTE
Flaps must stop prior to rollers making contact with the end of the
trackslots.
2 Turn one drive shaft coupling (RH or LH side) manually as far as necessary to
give the right flap the same angular setting as the left flap.
3 Connect and safety-wire the flexible drive shafts to the electric drive motor.
4 Move the selector switch to position RETRACTED and engage the flap motor
circuit breaker. Run the flaps from the retracted position to the fully extended
position. When the actual flap position reaches the selected position, the
appropriate limit switch must deenergize the flap motor.
CAUTION
Otherwise parts may be destroyed.
15° Limit Switch
1 Run the flaps by moving the selector to the 15° position. Install the flap
rigging tool, if not previously accomplished. Rigging the flaps to the defined
15° setting max require fine adjustment at the LH outboard transmission unit.
This can be accomplished by readjusting the nylon bushing positioned at the
end of the transmission screw that actuates both 15° limit switches.
2 Run the flaps to the 30° setting for removal of the LH outboard transmission
unit. Disconnect the outer flex drive shaft from the LH outboard trans- mission
actuator. Disconnect the transmission from the flap bracket. Remove the
transmission unit from the rear spar. Loosen the counter stop nut of the nylon
bushing. Rotating the nylon bushing in CW direction will shift the 15°
detection to the retracted position, rotating in CCW direction will shift it to the
extended position. Adjust as required and tighten the counter stop nut.
Reinstall transmission unit to the rear spar. Reinstall the transmission unit to
the rear spar. Connect the flex drive shaft to the transmission actuator.
3 Check that all bolts and joints are secured where necessary.
4 Check function of the position indicator. Green lights indicate the 15° and 30°
position and an additional yellow light indicating "flaps in transition". The
retracted position is indicated by the fact that no light is on.
5 Check the flap operation.
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
27-53-05
Flap Asymmetry Senders
Adjustment
This adjustment is required after the flaps have been rigged and checked for
normal operation. The asymmetry senders, one potentiometer at the LH side
and one at the RH side flap, are part of an electric system, the so-called
watchdog. The watchdog shuts off the flap motor when the difference between
the LH and RH side flap angular positions exceeds 7° ± 3°.
1 Lower the flaps by moving the selector to the 15° position.
2 Pull the flap motor circuit breaker. Ascertain that the flap control circuit
breaker is engaged. Turn the sensitivity control potentiometer of the
watchdog box towards maximum sensitivity.
3 Adjust the LH asymmetry detection potentiometer. Make sure that the arm is
loose on the shaft, then rotate the shaft to find out the potentiometer’s center
position between its two internal stops. The angular range of the potentiometer
is ± 170 °. Then tighten the arm’s clamping screw.
4 Adjust the RH asymmetry detection potentiometer to ensure that the angular
travel to engage the watchdog is the same when retracting as when extending
the flaps. Make sure that the arm is loose on the shaft, then rotate the shaft in
CW direction until the red asymmetry indicator light on the watchdog box
appears (simultaneously the red light on the warning panel in the cockpit
appears). Mark this angular shaft position. Rotate the shaft in CCW direction.
The red indicator light will turn off, then light up again after rotating a few
degrees. Mark this position, too.
5 Finally rotate the sender shaft to the middle between the two marks and
tighten the arm’s clamping screw.
Now the two potentiometers feature the same resistance value at a given flap
position.
After adjusting, check for correct alignment of asymmetry detection
sensitivity:
6 With the flaps in 15° position disconnect the RH flex drive shaft from the
electric drive motor. Engage the flap motor circuit breaker and move the
selector switch to the UP position. The LH flap will move up while the RH
flap will stay in the 15° position. After a certain difference in RH and LH flap
angular positions is reached the watchdog shuts off the flap motor.
7 Measure the flap travel. If it is within the limit of 7° ± 3° , proceed with
step 11. If it is outside that limit, proceed with step 8.
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Maintenance Manual and Illustrated Parts Catalogue
Extra EA -400
Flight Controls
8 In order to drive the LH flap back to its 15° position, disconnect the watchdog
box from the flap control box, pull the flap motor circuit breaker, move the
selector switch to the 15° position and engage the flap motor circuit breaker.
CAUTION
The flap starts to move back to the 15° position immediately after
engaging the circuit breaker.
9 Reconnect the watchdog box to the flap control box.
10 Adjust the sensitivity control potentiometer by turning it in the proper
direction, then repeat steps 6 to 7.
After asymmetry has been adjusted for UP motion repeat this procedure for
DOWN motion:
11 Move the selector switch to the DOWN position. The LH flap will move
down while the RH flap will stay in the 15° position. When a certain
difference in RH and LH flap angular positions is reached the watchdog shuts
off the flap motor.
12 Measure the flap travel. If it is within the limit of 7° ± 3° , proceed with step
16. If it is outside that limit, proceed with step 13.
13 In order to drive the LH flap back to its 15° position, disconnect the watchdog
box from the flap control box, pull the flap motor circuit breaker, move the
selector switch to the 15° position and engage the flap motor circuit breaker.
CAUTION
The flap starts to move back to the 15° position immediately after
engaging the circuit breaker.
14 Reconnect the watchdog box to the flap control box.
15 Adjust the sensitivity control potentiometer by turning it in the proper
direction, but do not turn it in a way that would compromise the setting found
in step 7. Then repeat steps 11 to 12.
16 Connect and safety-wire the RH flexible drive shaft to the electric drive
motor.
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