SDR CALA2013101892177

Service difficulty report · Wire · Boeing 747422

Difficulty date: October 18, 2013
Submitted: October 22, 2013
Operation: Air carrier
Aircraft: N171UA
Make and model: Boeing 747422
Aircraft serial: 24322
Aircraft time: 91,679 hours, 10,771 cycles
Engine: Pwa PW4056
System (JASC): 2797 · Flight Control System Wiring
Part: Wire
Condition: Damaged
Location: Stab Trim
Stage of operation: NR
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

"STAB TRIM" STATUS MESSAGE DISPLAYED UPON T TRIMMING STAB NOSE UP WITH "ALTERNATE STAB TRIM SWITCHES" ON PEDESTAL. CMC SHOWS MESSAGE 27147. WITH NR 2 CUTOUT SW ENGAGED ONLY NR 3 IN CUTOUT POS STAB TRIM FAILS TO MOVE TO THE NOSE UP POSITION WITH "ALTERNATE STAB TRIM SWITCHES". SUSPECT RT STAB TRIM CONTROL MODULE B188 AT FAULT. PLACED RT STCM IAW AMM 27-41 -04-201, NO HELP. FOUND DAMAGED WIRE AT S19 6O. REPLACED SWITCH IAW TO MM 27-41-08 PG 401 & SYSTEM CHECKED NORMAL IAW TO MM 27-41-08 PG501.