Service difficulty report · Servo Valve · Boeing 747422

Difficulty date
January 2, 2012
Submitted
January 26, 2012
Operation
Air carrier
Aircraft
N174UA
Make and model
Boeing 747422
Aircraft serial
24381
Aircraft time
85,411 hours, 9,576 cycles
Engine
Pwa PW4056
Part
Servo Valve
Part number
A71882003
Part serial
20878
Condition
No Test
Location
Lt Aileron
Stage of operation
IN
How discovered
9
Nature of condition
O
Precautionary procedure
K

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

What was found

LEFT AILERON SERVO FAILED OPERATIONAL TEST AND FCC BITE TEST. REMOVED SERVO IAW AMM. INSTALLED LT LCCA SERVO VALVE PER AMM. LEAK CHECKED GOOD, FAILED OPERATIONAL TEST WITH CMCS MESSAGE "AILERON SERVO-L, FCC-L INTERFACE FAIL SERVO POSITION 22055." REPLACED CLCP RT WHEEL WELL PER MM. OPS CHECKED GOOD.