SDR ASAA2017032520248

Service difficulty report · Sensor · Boeing 737890

Difficulty date: March 25, 2017
Submitted: March 29, 2017
Operation: Air carrier
Aircraft: N558AS
Make and model: Boeing 737890
Aircraft serial: 35177
Aircraft time: 41,040 hours, 12,025 cycles
System (JASC): 2150 · Cabin Cooling System
Part: Sensor
Part number: MS280341
Condition: Failed
Location: Lt A/C Pack Temp
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

INDICATED TEMP OF LEFT PACK OUTPUT IS OFF THE SCALE, HIGH. ALL ZONES ARE CONTROLLABLE AND COMFORTABLE. DUCT PRESSURE IS BALANCED, 43 PSI. ACFT GROUNDED. WDM 21-61-51 AND AMM 21-51-60-400-801. VERIFIED TEMP NEEDLE ON INDICATOR PEGS OUT WHEN LEFT PACK SELECTED ON PANEL. CHECKED CONNECTOR D3920 AND LEFT PACK TEMP BULB T488. HIGH ERRATIC RESISTANCE VALUES AT PACK TEMP BULB READ. REMOVED AND REPLACED LEFT PACK TEMP SENSOR BULB. OPS TEST NORMAL.