Appendix-B
1.0 Environmental Stress Screening (MIL-STD-2164)
1.1 Introduction
Environmental Stress Screening (ESS) is carried out as part of the Acceptance Test
Plan (ATP) for each of the delivered Production Units. The ESS is based on Military
Standards for Environmental Stress Screening Process for Electronic LRUs, viz., MILSTD-2164 (EC) and DOD-HDBK-344 (USAF).
The ESS test severities and screening methods have been chosen to simulate realistic
operational environment of the Radar Subsystems and to provoke the latent defects in
the test item, without either degrading its performance or damaging its operational life.
Monitoring of specific performance parameters of the test item shall be carried out
during the screening tests.
1.2 Power Burn-in
The test item will be powered „ON‟ continuously for 8 hours at +65°C. After
completion of the „Power Burn-in‟ and recovery of the item to ambient conditions, the
test item shall be subjected to VE and a PC and record the results.
1.3 Random Vibration (Pre-Thermal-Cycling) Test
The Random Vibration test will be carried out along all the three mutually
perpendicular axes for duration of five minutes each, as per profile given in Fig.2-1 on
all the test items. The LRUs shall be kept energized during the vibration test. Visual
Examination will be carried out after the test to check for appearance of any defect and
record the results.
0.04
PSD
g2 / Hz
+ 3 dB /
Octave
- 3 dB /
Octave
0.01
grms = 6.06
20
Figure. 1-1
80
350
FREQUENCY (Hz)
ESS - Random Vibration Test Profile
2000
1.4
Thermal Cycling Test
The test item will be subjected to the temperature extremes of -20oC and +55oC for
ten cycles as per profile given in Fig.1-2.
Full Cycle
+55
T
e
m
p
e
r
a
t
u
r
e
DWELL
POWER ‘ON’
POWER ‘OFF’
AMBIENT
TEMPERATURE
PC
POWER ‘ON’ PC
-20
DWELL
90
90
90
30
o
DWELL
30
Time (min)
( C)
Figure 6-2
: Thermal
Test
Profile Test Profile
Fig.1-2
: ESS -Cycling
Thermal
Cycling
The rate-of-change of temperature from minimum to maximum, and vice versa, shall be
at an average rate of 5 oC/min. The test item shall be powered and the PC taken as
indicated in the figure, during each cycle and record the results. In Thermal Cycling
Test, there should be 10 cycles out of which last 3 cycles should be defect-free. In case of
any defects in the last 3 cycles, the complete test i.e. 10 cycles is required to be repeated.
Also the dwell time should be 90 minutes at each peak. Power “ON” and testing of the
unit is as per Fig. 1-2
1.5
Random Vibration (Post-Thermal-Cycling) Test
The Random Vibration Test will be repeated after the Thermal Cycling Test and the
Test-Item visually examined for appearance of any defect and record the results.
1.6
Performance Verification
PC will be carried out before and after carrying out each of the tests. A total verification
and measurement of performance parameters will be carried out finally under ambient
conditions of the test site. The pass criterion will be that the Test Item performs well
within the acceptable limits of the performance parameters.
2.0
SL.
No.
1.
2.
3.
4.
Safety of Flight Tests (SoFT) on FTB (Propeller Aircraft)
TEST
Initial Visual
Examination
(VE) and
Performance
Check (PC)
Initial
Insulation
and Isolation
Resistance
Bond
Resistance
Vibration
(MIL-STD810D
Method
514.3)
TEST CONDITIONS
At ambient condition
REMARKS
Check for finishes, workman
ship defects and mounting
during visual examination and
record the observations.
To be carried out at 500V DC between
equipment body and connector pins
(shorted together with active components
disconnected) and between insulated live
parts (As per BS2G – 100, Part – II).
IR measured to be better than 20 M
Ohms.
All bonds for ground conductors, whose
primary function is to provide a path for
power, control or signal currents and
lightning protection shall have a
maximum DC resistance of 2.5 milliohm.
The resistance across joints or seams in
metallic members required to provide
electromagnetic shielding shall also be 1
milliohm or less.
Initial Resonance Search at 0.5g/1.0g
from 5 Hz to 2000 Hz
The test will be conducted with
the test item hard mounted. First
four Fundamental resonance
which are having amplification
greater than 3 i.e. Q>3 only to be
recorded. The resonances
recorded should not coincide
with the platform fundamental
frequencies.
Equipment in `OFF‟ condition.
(b)
Endurance
by
random
Vibration test
(15 Min./axis in all 3 axes)
Method 514.3, Category –4,
Para I – 3.2.4, Figure 514.3-25(a)
The test will be conducted with the test item either hard
mounted or in a tray with suitable shock mounts
depending upon the actual fitment on the platform.
Equipment will be `ON‟ and important parameters
monitored continuously during the test.
Figure 2-1 Random-on-Random (Propeller – Aircraft)
(c )Final Resonance Search as in (a) above and any deviation
from the initial resonance search noticed should be recorded.
VE and PC at the end of the
test.
5
High
Temperature
Storage cum
Operation
As per MIL –
STD –
Method 501.2, Procedure – I & II
Duration
: 3 cycles
810D PC as shown in profile and
after recovery. Visual
examination shall be carried
out after the test.
Operation at 55C for one hour and storage at
70C as per figure 2-2
Figure 2-2 Diurnal Cycle for High Temperature Storage cum Operation
6
Low
Temperature
Storage cum
Operation
As per MIL – STD – 810D
Method 502.2
PC during last ½ hour and
PC after recovery.
Storage cum Operation:–20ºC, ±2ºC
Duration : 24 hrs
(As per profile in Fig:2-3)
Figure 2-3 Low Temperature Storage cum Operation test
7
Low
Pressure
(Altitude)
As
per
Method 500.2,
Procedure II
MIL–STD–810D PC during last 1/2 hour
and after recovery.
Altitude: 3000mt(1000ft).
Altitude change rate:
2000ft/min(10m/s)
Duration: 4 Hours
Temperature : –20ºC
Test Profile as shown below in Fig
– 2-4.
Figure: 2-4
Altitude Test
8
Humidity
As per MIL-STD-810D
Method 507.2, Fig
507.2 – I
Cycle: 1
Table 507.2 – II
Temperature & RH: as
per profile in Fig 6-5
below
Duration: 1 cycle
Figure 2-5
(i)
(ii)
PC during last 1/2 hour and
after recovery.
VE & PC after recovery.
(iii)
(iv)
Humidity
9
Acceleration
test
(MIL-STD810D
Method 513.3)
Procedure -II
Functional:
Severity: Up 7.0g,Down 3.0g,Lat
L& Lat R 4.0g,Fore & Aft 2.0g
Structural:
Severity: 1.5 times the levels given
above
Duration: 1 min along each
direction
P.C before and after the test
Visual examination shall be
carried out after the test
10
Shock
(MIL-STD810D Method
516.3-8)
Functional :
Severity
: 15g, 11 m sec
Pulse shape : Half Sine Pulse
No. of shocks : 3 shocks on each
of 6 directions
Total of 18 shocks.
Equipment in `ON‟ condition
VE and PC during and after
the test.
Equipment in unpacked
condition mounted on a
suitable fixture.
Crash Safety :
Severity
: 30g, 11 m sec
Pulse
: Half Sine Pulse
No. of shocks: 2 shocks in each of
6
directions.
Total of 12 shocks.
Mechanical weight equivalent
Mock-up may be used for the
test. VE after the test.
11
Final Insulation
/ Isolation
Resistance
To be carried out at 500V DC
between equipment body and
connector pins (shorted together
IR measured to be > 5 M
with
active
components
ohms
disconnected)
and
between
insulated live parts (As per BS2G –
100, Part – II).
12
Final Visual
Examination
and
Performance
Check
Check for deterioration of
Final visual examination and
finishes, workmanship defects
performance check at room
and mountings during visual
ambient
conditions
at
the
examination and record the
conclusion of all the tests.
observations.
3.0
EMI/EMC Tests (MIL-STD-461E)
Description
Frequency
Range
CE102
Conducted Emissions All
Power Leads individually
10KHz to 10MHz
CE106
Conducted Emissions
Antenna Terminals only
CS101
Conducted susceptibility
High-Sides of Power Leads
only
CS114
Conducted Susceptibility
Bulk cable Injection All
Interconnecting Cables
Conducted Susceptibility
Bulk cable Injection All
Interconnecting Cables
Conducted Susceptibility
Cables and Power Leads All
Interconnecting Cables
Test
CS115
CS116
RE102
Radiated Emissions, Electric
Field
RS103
Radiated Susceptibility,
Electric Field
Remarks
Basic Limit Curve : for
28Vdc
9dB Relaxation : for 230
Ac
10MHz to 40GHz 34 dBV :
Receive/Standby Mode (50+10log P)dBc for 2nd &
3rd Harmonics and –80
dBc for others: Transmit
Mode
100Hz to 150KHz (Voltage) Limit Curve #1:
for 230V AC
(Voltage) Limit Curve #2 :
for 28VDC
10KHz to
Curve #5 : 10KHz200MHz
200MHz
Impulse
Excitation
10KHz to
100MHz Damped
Sinusoidal
Transients
2 MHz to 18GHz
30MHz to 40GHz
Imax = 5 A
Airforce (Air
Applications) Limit
Curve.
E = 200 V/m