Service difficulty report · Control Valve · Boeing 737990ER

Difficulty date
February 2, 2018
Submitted
February 5, 2018
Operation
Air carrier
Aircraft
N419AS
Make and model
Boeing 737990ER
Aircraft serial
41734
Aircraft time
19,448 hours, 6,401 cycles
Part
Control Valve
Part number
3989083
Part serial
19001
Condition
Failed
Location
Lt A/C Pack
Part time
19,461 hours, 1,779 cycles
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

LH PACK LIGHT ILLUMINATES ON RECALL. RESETS WITH MASTER CAUTION RESET. GROUNDED - YES. PERFORMED LH PACK/ZONE TEMP CONTROLLER BITE TEST PER B737-900 AMM 21-61-00. BITE TEST REVEALED LH TEMP CONTROL VALVE FAILURE. REMOVED AND REPLACED LH TEMP CONTROL VALVE PER AMM 21-51-10. BITE TEST GOOD. OPERATIONAL TEST GOOD. LEAK CHECK GOOD. THIS CLEARS MEL 21-32B.