Service difficulty report · Sensor · Boeing 737990ER

Difficulty date
February 5, 2018
Submitted
February 7, 2018
Operation
Air carrier
Aircraft
N493AS
Make and model
Boeing 737990ER
Aircraft serial
41727
Aircraft time
7,045 hours, 2,378 cycles
Part
Sensor
Condition
Dirty
Location
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

CONTROL CABIN AIR TEMP IS VERY COLD. TEMP CONTROLLER HAS NO NOTICEABLE EFFECT ON AIR TEMP, EXCEPT WHEN TRIM AIR SWITCH IS OFF. WITH TRIM AIR OFF, TEMP CONTROLLER SEEMS TO WORK NORMALLY. ACFT GROUNDED. PERFORMED A BITE CHECK OF THE NR 1 AND 2 PFTC IAW AMM 21-61-00, OPS NORMAL, NO FAULTS LOGGED. FA`S STATED FWD CABIN WAS TOO WARM AND INFORMED THE PILOTS ON TWO OCCASIONS. CONFIRMED NO FAULTS ON CABIN TEMP CONTROLLERS IAW FIM 21-62 TASK 801. FOUND CONTROL CABIN AND FWD PASSENGER CABIN TEMP SENSOR ASSY FILTER DIRTY AND FWD PASSENGER CABIN TEMP SENSOR DIRTY. CLEANED THE SENSORS IAW AMM 21-61-10, AND REPLACED TEMP SENSOR FILTERS IAW AMM 21-61-06. OPERATED BOTH PACKS FOR SEVERAL MINUTES. OPS NORMAL. NO FAULTS NOTED. WITH TRIM AIR SWITCH ON, CONTROL CABIN GOT VERY WARM WITH TEMP SELECTOR FULL WARM AND COMFORTABLE WITH SELECTOR IN AUTO. FWD PAX CABIN RESPONDED THE SAME.