SDR AALA202303289741

Service difficulty report · Gcu · Boeing 737823

Difficulty date: March 18, 2023
Submitted: March 28, 2023
Operation: Air carrier
Aircraft: N951AA
Make and model: Boeing 737823
Aircraft serial: 29538
Aircraft time: 59,806 hours, 24,836 cycles
System (JASC): 2421 · AC Generator-Alternator
Part: Gcu
Condition: Fault Message
Location: Zone 100 - Fuse
Stage of operation: DE
How discovered: O
Nature of condition: F, J
Precautionary procedure: O

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

What was found

AIRCRAFT WAS GROUNDED: JUST PRIOR TO TOP OF DESCENT LEFT TRANSFER BUS OFF, LEFT SOURCE OFF BOTH ILLUMINATED SIMULTANEOUSLY: AFTER QUICK REFERENCE HANDBOOK PROCEDURE TRANSFER BUSS OFF LIGHT REMAINED ILLUMINATED. EMERGENCY WAS DECLARED IN LAS. SWAPPED AUXILIARY POWER UNIT GENERATOR CONTROL UNIT WITH NUMBER 1 GENERATOR CONTROL UNIT. FAULT CLEARED RAN ENGINES ACCOMPLISHED ELECTRICAL TESTS OF GENERATOR CONTROL UNIT OPERATED NORMAL.