Service difficulty report · Control Valve · Boeing 737990ER

Difficulty date
March 4, 2017
Submitted
March 7, 2017
Operation
Air carrier
Aircraft
N428AS
Make and model
Boeing 737990ER
Aircraft serial
36353
Aircraft time
4,001 hours, 1,327 cycles
Part
Control Valve
Part number
3989085
Part serial
26198
Condition
Failed
Location
Lt A/C Pack
Part time
4,006 hours, 1,329 cycles
Stage of operation
TX
How discovered
O
Nature of condition
J
Precautionary procedure
D

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

What was found

CONTROL CABIN ZONE TEMP LIGHT ILLUMINATED WITH RECALL ON TAXI OUT. ACFT GROUNDED. ACCOMPLISHED LEFT CONTROLLER BITE IAW FIM 21-62 TASK 801. FOUND FAULT CODE 21-51510, SEVERAL TIMES. REMOVED AND REPLACED THE LT SIDE TEMP CONTROL VALVE IAW AMM 21-51-10. LEAK CHECKED GOOD. FOUND RIGHT PACK KEPT SHOWING FAULT CODE 21-51267. RIGHT TEMP CONTROL VALVE FAULT. REMOVED AND REPLACED THE RT SIDE TEMP CONTROL VALVE IAW AMM 21-51-10. LEAK CHECKED GOOD. ACCOMPLISHED REPAIR CONFIRMATION, PERFORMED BITE PROCEDURE ON BOTH PACK CONTROLLERS. ALL FAULTS ARE CLEAR AND SYSTEM IS OPS CHECKING NORMAL. GROUND VERIFICATION COMPLETED IAW FIM BITE 21-62 TASK 801.