SDR ASAA2013061395111

Service difficulty report · Sensor · Boeing 737990ER

Difficulty date: June 13, 2013
Submitted: June 18, 2013
Operation: Air carrier
Aircraft: N413AS
Make and model: Boeing 737990ER
Aircraft serial: 35205
Aircraft time: 826 hours, 268 cycles
System (JASC): 4960 · APU Controls
Part: Sensor
Part number: 38762231
Condition: Overspeed
Location: Apu
Stage of operation: TX
How discovered: O
Nature of condition: J
Precautionary procedure: O

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

What was found

PRIOR TO PUSH BACK, WHILE APU PROVIDING AIR AND ELECTRICS, APU OVERSPEED LIGHT ILLUMINATED AND APU SHUTDOWN. ACFT GROUNDED. RANG P12, PINS 1-2, 13 OHMS, 3-4 20 OHMS. NO BENT OR PUSHED PINS. REPLACED SPEED SENSOR. NO LEAK NOTED. APU OPS NORMAL REF AMM49-61-21-000-801, 49-61-21-400-801.