TM 55-1520-240-T
4-12.4 FULL AUTHORITY DIGITAL ELECTRONIC CONTROL (FADEC) OPERATIONAL CHECK
4-12.4
INITIAL SETUP
References:
Applicable Configurations:
TM 55-1520-240-23
With 74
Equipment Condition:
Tools:
TM 55-1520-240-23:
Electrical Repairer's Tool Kit,
Battery Connected
NSN 5180-00-323-4915
Electrical Power On
Materials:
Hydraulic Power On
None
Visual Check of FADEC Performed (Task 4-12.3)
Personnel Required:
Aircraft Electrician
TASK
RESULT
1.
Check that ENGINE NO. 1 PRI CONT, REV CONT and
If circuit breaker (1, 2 or 3) is open, close it. If circuit
START & IGN circuit breakers (1, 2 and 3) are closed.
breaker (1, 2 or 3) opens again, go to task 4-12.5,
task 4-12.6 or task 4-10.5, respectively.
2.
Check that ENGINE NO. 2 PRI CONT, REV CONT and
If circuit breaker (4, 5 or 6) is open, close it. If circuit
START & IGN circuit breakers (4, 5 and 6) are closed.
breaker (4, 5 or 6) opens again, go to task 4-12.5,
task 4-12.6 or task 4-10.6, respectively.
3.
On FADEC control panel (7), set 1 and 2 PRI/ REV
Cautions (10 and 11) should be out. If either caution is
switches (8 and 9) to PRI. Check FADEC 1 and FADEC illuminated, go to task 4-12.7.
2 cautions (10 and 11).
4.
Look at fault display (12) on DECU No. 1 and No. 2 (13
Display should show 88. If any other code shown, copy
and 14).
code and refer to Table 1 for maintenance action.
5.
On ENGINE CONDITION quadrant (15), move NO. 1
Each display should show 88. If any other code shown,
and NO. 2 levers (16 and 17) to GROUND. Look at
copy code and refer to Table 1 for maintenance action.
fault display (12) on DECU No. 1 and No. 2 (13 and 14).
6.
Open ENGINE NO. 1 and NO. 2 PRI CONT circuit
Cautions (10 and 11) should be illuminated. Fault display
breakers (1 and 4). Check FADEC 1 and 2 cautions (10
(12) on both DECUs (13 and 14) should be blank.
and 11) and fault display (12).
7.
Open ENGINE NO. 1 REV CONT circuit breaker (2).
Caution (10) should go out. DECU No. 1 display should
Close ENGINE NO. 1 PRI CONT circuit breaker (1).
show code A6. If it does not, replace DECU No. 1.
Move 1 PRI/ REV switch (8) to REV and back to PRI.
Check FADEC 1 caution (10) and fault display (12).
8.
Close ENGINE NO. 1 REV CONT circuit breaker (2).
Caution (10) shall illuminate.
Open ENGINE NO. 1 PRI CONT circuit breaker (1).
9.
Open ENGINE NO. 2 REV CONT circuit breaker (5).
Caution (11) should go out. DECU No. 2 display should
Close ENGINE NO. 2 PRI CONT circuit breaker (4).
show code A6. If it does not, replace DECU No. 2.
Move 2 PRI/ REV switch (11) to REV and back to PRI.
Check FADEC 2 caution (11) and fault display (12) on
DECU (14).
TASK
RESULT
10.
Close ENGINE NO. 2 REV CONT circuit breaker (5).
Caution (11) shall illuminate.
Close ENGINE NO. 1 PRI CONT circuit breaker (1).
11.
Move pilot's thrust control (18) through its range.
Fault display (12) on both DECUs (13 and 14) should
Check fault display (12) on DECU No. 1 and No. 2 (13
show 88. If not, copy code and refer to Table 1 for
and 14).
maintenance action.
12.
On ENGINE CONDITION quadrant (15), move NO. 1
and NO. 2 levers (16 and 17) to STOP.
FOLLOW-ON MAINTENANCE:
TM 55-1520-240-23:
Hydraulic power off.
Electrical power off.
Battery disconnected.
Table 1. DECU FAULT DISPLAY CODE MAINTENANCE ACTION
FAULT
MAINTENANCE ACTION/
FAULT
MAINTENANCE ACTION/
CODE
REFER TO TASK
CODE
REFER TO TASK
10 to 18
Replace DECU.
D0
Replace DECU.
1B and 1C
Replace DECU.
D1
Refer to task 4-12.33.
1E and 1F
Replace DECU
D2
Refer to task 4-12.34.
A1
Refer to task 4-12.8.
D3 to D9
Replace DECU.
A2
Refer to task 4-12.9.
DA to DD
Replace DECU.
A3
Refer to task 4-12.10.
DE
Refer to task 4-12.35.
A4
Refer to task 4-12.11.
DF
Replace DECU.
A5
Refer to task 4-12.12.
E1
Refer to task 4-12.19.
A6
Refer to task 4-12.13.
E2
Refer to task 4-12.20.
A7
Refer to task 4-12.14.
E3
Refer to task 4-12.21.
B2
Refer to task 4-12.24.
E4
Refer to task 4-12.22.
B3
Refer to task 4-12.22.
E5
Replace N2 Sensor.
B4
Refer to task 4-12.19.
Fl
Refer to task 4-12.23.
B5
Refer to task 4-12.10.
F2
Refer to task 4-12.24.
B6
Refer to task 4-5.4.
F3
Replace HMU.
B7
Refer to task 4-12.27.
F4
Refer to task 4-12.25.
B9
Replace DECU.
F5
Refer to task 4-12.26.
BA to BC
Replace DECU.
F6
Refer to task 4-12.27.
C1 to C8
F7
Refer to task 4-12.28.
and CF
Refer to task 4-12.15 or 4-12.16.
F8
Refer to task 4-12.29.
C1 to C8
Replace other DECU.
F9
Refer to task 4-12.30.
C9
Refer to task 4-12.17 or 4-12.18.
FA
Refer to task 4-12.31.
CF
Replace other DECU.
FB
Refer to task 4-12.32.
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