SDR ASAA2020092133215

Service difficulty report · Control Valve · Boeing 737990ER

Difficulty date: September 21, 2020
Submitted: September 24, 2020
Operation: Air carrier
Aircraft: N491AS
Make and model: Boeing 737990ER
Aircraft serial: 44109
Aircraft time: 18,655 hours, 5,967 cycles
System (JASC): 2160 · Cabin Temperature Control System
Part: Control Valve
Part number: 3989083
Part serial: 10777
Condition: Faulted
Location: Cockpit Temp
Part time: 44,769 hours, 13,635 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

CONT CAB ZONE TEMP ILLUMINATES DURING MASTER CAUTION RECALL, EXTINGUISHES WITH MASTER CAUTION RESET. GROUNDED-YES. ACCOMPLISHED BITE CHECK OF NR 2 ZONE TEMP CONTROLLER, SHOWS FAULT TCV, REF B737-800 AMM 21-61-21/401. REMOVED AND REPLACED FLIGHT DECK PRIMARY TEMP CONTROL VALVE. OPS, LEAK, AND BITE CHECK GOOD.