Service difficulty report · Unknown · Boeing 737890

Difficulty date
May 12, 2019
Submitted
May 13, 2019
Operation
Air carrier
Aircraft
N570AS
Make and model
Boeing 737890
Aircraft serial
35185
Aircraft time
46,326 hours, 13,771 cycles
Part
Unknown
Condition
Malfunctioned
Location
Cabin Temp
Stage of operation
NR
How discovered
O
Nature of condition
O
Precautionary procedure
K

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

What was found

FORWARD CABIN HEAT DOES NOT FUNCTION PROPERLY. THE FORWARD CABIN REMAINS COLD AT 20C, WITH THE FORWARD SUPPLY DUCT TEMPERATURE AT 20C. AS THE FORWARD TEMPERATURE CONTROL KNOB IS ROTATED VERY GRADUALLY CLOCKWISE, THERE IS NO RESPONSE IN THE FORWARD SUPPLY DUCT TEMPERATURE. THE CONDITION REMAINS THE SAME UNTIL THE TEMP CONTROL KNOB NEARS THE 230 POSITION, AND THEN THE FORWARD SUPPLY TEMPERATURE RUNS AWAY TO 60-70C. STABLE TEMP CONTROL IS POSSIBLE ONLY AT 20C. GROUNDED - YES. RESTARTED SYSTEM AND RAN OPS TEST AS WELL AS BITE TEST OF THE CABIN ZONE TEMP CONTROLLERS PER AMM 21-61-00. NOTED NO DEFECTS AND FOUND OPERATION OF PACKS TO BE NORMAL.