SDR ASAA2013041994550

Service difficulty report · Apu · Boeing 737890

Difficulty date: April 19, 2013
Submitted: April 23, 2013
Operation: Air carrier
Aircraft: N506AS
Make and model: Boeing 737890
Aircraft serial: 35690
Aircraft time: 18,665 hours, 5,863 cycles
System (JASC): 4900 · Airborne Auxiliary Power Unit (APU) System
Part: Apu
Condition: Failed
Stage of operation: TX
How discovered: O
Nature of condition: J
Precautionary procedure: D

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

What was found

DURING PUSHBACK, APU FAILED. TROUBLESHOOTING, APU BITE TEST SHOWED NO CURRENT FAULTS, FAULT CODE 49-91007 WAS LOGGED IN FAULT HISTORY. APU STARTED AND OPERATED NORMALLY. INSPECTED MAG. DRAIN PLUG FOR PARTICLES IAW MM 49-11-01, NO DEFECTS NOTED. MANUALLY TURNED APU IAW MM 49-21-00, NO DEFECTS NOTED. INSPECTED THE WIRE HARNESS IAW MM 49-11-01, NO DEFECTS NOTED. REPLACED THE LOW OIL PRESSURE SWITCH IAW MM 49-94-22, LK AND OPS CKS GOOD. REPLACED THE LUBE MODULE IAW MM 49-91-11, LK AND OPS CKS GOOD.