SDR 2003UALA00742

Service difficulty report · A/C Pack · Boeing 777222

Difficulty date: October 5, 2003
Submitted: October 14, 2003
Operation: Air carrier
Aircraft: N796UA
Make and model: Boeing 777222
Aircraft serial: 26931
Aircraft time: 25,294 hours, 3,859 cycles
Engine: Pwa PW4090
System (JASC): 2150 · Cabin Cooling System
Part: A/C Pack
Condition: Odor
Stage of operation: NR
How discovered: 9
Nature of condition: B
Precautionary procedure: O

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

What was found

RANCID ODOR COMING AIR CONDITIONER. SMOKE OR FUMES IN CABIN. APU WAS REPLACED AND SHOP DISASSEMBLED GEARBOX AND LOAD COMPRESSOR. ENGINEERING FOUND INDICATIONS THAT THE LOAD COMPRESSOR FRONT CARBON SEAL TO BE THE ROOT CAUSE FOR ODOR IN CABIN. THE LOAD COMPRESSOR CARBON SEAL HOUSING WAS FOUND BULGED AND WITH HEAT DAMAGE TO INNER LIP SEAL RESULTING IN COKING ON SEAL ROTOR. CARBON SEAL, SEAL ROTOR, BEARING, AND BACK SCHROUD REPLACED.