SDR ASAA2015101513511

Service difficulty report · Controller · Boeing 737990ER

Difficulty date: October 15, 2015
Submitted: October 20, 2015
Operation: Air carrier
Aircraft: N486AS
Make and model: Boeing 737990ER
Aircraft serial: 44107
Aircraft time: 187 hours, 64 cycles
System (JASC): 2160 · Cabin Temperature Control System
Part: Controller
Condition: Malfunctioned
Location: Cabin Temp
Stage of operation: NR
How discovered: 9
Nature of condition: O
Precautionary procedure: O

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

What was found

TEMP CONTROL IN ALL 3 ZONES "HYPER-SENSITIVE", LARGER THAN USUAL SUPPLY DUCT TEMP CHANGES WITH SMALL ADJUSTMENTS. CONDITION MOST PRONOUNCED AFTER ENGINE START & TAKE OFF, THEN IMPROVED ENROUTE. WHEN TEMP SELECTORS OFF: ON GROUND SUPPLY DUST TEMP IN ALL 3 ZONES INDICATES 38-40C IN FLIGHT, CONTROL CAB INDICATES 38-40C, FWD & AFT CAB INDICATOR NORMAL 20-22C. ACFT GROUNDED. REF AMM 21-62, TASK 801 BITE CK SYS. NO FAULTS FOUND. CYCLED PACKS HOT/COLD. OPS NORMAL. NO 30DAY HISTORY. OK FOR SERVICE.