Service difficulty report · Pcu · Boeing 737790

Difficulty date
February 3, 2024
Submitted
February 5, 2024
Operation
Air carrier
Aircraft
N625AS
Make and model
Boeing 737790
Aircraft serial
30792
Aircraft time
70,922 hours, 37,155 cycles
Part
Pcu
Part number
762187F
Part serial
0752
Condition
Faulty
Location
E/E Shelf E4-2
Part time
72,920 hours, 38,221 cycles
Stage of operation
CR
How discovered
O
Nature of condition
H
Precautionary procedure
A

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

WHILE FLYING WITH MEL 24-1B WITH #1 GEN INOP (SEE 60726816) AND DESCENDING THROUGH FL 250 THE APU GENERATOR WENT OFF LINE WITH 0 VOLTS 0 FREQS. AT APPROXIMATLLY FL 200 THE #2 GE WENT OFFLINE FOR ABOUT 45 SECONDS. WE WERE ABLE TO RESET @3 GEN WHICH CAME BACK ONLINE WITH 115 VOLST/ 400 FREQS. WE LANDED WITH #2 GEN ONLY. GROUNDED - YES. WITH POWER REMOVED, PERFORMED INSP OF C/B'S, ALL C/B'S REMAIN SET. APPLIED EXTERNAL POWER, PREFORMED GCU BITE, UPON ARRIVAL AND POWER UP, #1 GCU FAULT IDG LIGHT, #2 GCU FAULT IDG LIGHT, AND APU GCU FAULT GCU. AFTER PRESSING GCU TEST #1 GCU, #2 GCU, AND APU GCU BITE PASS REF FIM 24-21 TASK 801. BPCU BITE FAULTS EPC ON BOTH BATTERY ONLY AND BATTERY PLUS EXTERNAL POWER REF FIM 24-41 TASK 801. CDANCIK 56558 02/03/2024 REF FIM 24-41 TASK 804, REPLACED EPC REF AMM 24-41-12. REPLACED BPCU PRECAUTIONARY REF MM 24-41-21. INSTALLATION TESTS OP CK GOOD FOR BOTH. WHILE RUNNNING BOTH ENGINES + APU CYCLED POWER BACK AND FORTH. OP CK NORMAL WITH NO FAULTS. VMULDREW 47631 02/03/2024. REF LOG PG 60726822 FOR APU REMOVE AND REPLACE ASA 57797 02/03/2024. REF TSR715559 FOR ADDITIONAL WORK ACCOMPLISHED. ACCOMPLISHED IAI SUPP AMM 24-21-00-700-803 A/C GEN OP TESTS WITH NO DEFECTS NOTED.