SDR UALA2012042702520

Service difficulty report · Apu · Boeing 767322

Difficulty date: April 25, 2012
Submitted: May 25, 2012
Operation: Air carrier
Aircraft: N641UA
Make and model: Boeing 767322
Aircraft serial: 25091
Aircraft time: 89,228 hours, 14,245 cycles
Engine: Pwa PW4060
System (JASC): 4900 · Airborne Auxiliary Power Unit (APU) System
Part: Apu
Condition: Malfunctioned
Stage of operation: NR
How discovered: 9
Nature of condition: O
Precautionary procedure: O

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

What was found

APU FAILED TWICE WHEN PNEU WAS IN USE. CHECKED CHIP DETECTORS ON APU, ALL GOOD. SERVICE WITH OIL. REPLACED APU BATTERY CHARGER IAW AMM, OPS CHECKED GOOD. RAN APU UNDER LOAD FOR 1 HALF HOUR RAN GOOD. APU AUTO SHUTDOWN AFTER OPERATING FOR 3 MINUTES. 5TH AUTO SHUTDOWN IN 3 DAYS. REPLACED GENERATOR FILTER DIFFERENTIAL PRESSURE SWITCH IAW MM, RAN AND SHUTDOWN MULTIPLE TIMES, CHECKED OK.