Service difficulty report · Modulating Valve · Boeing 737890

Difficulty date
August 28, 2023
Submitted
August 30, 2023
Operation
Air carrier
Aircraft
N535AS
Make and model
Boeing 737890
Aircraft serial
35200
Aircraft time
45,448 hours, 13,075 cycles
Part
Modulating Valve
Part number
3989083
Part serial
13528
Condition
Faulty
Location
Left Ecs Bay
Part time
47,901 hours, 13,985 cycles
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

TO MAINTAIN NORMAL TEMPERATURE IN MAIN CABIN, REQUIRED BOTH FWD CABIN AND AFT CABIN TEMPERATURE CONTROLLERS TO BE POSITIONED TO FULL COLD. GROUNDED - YES. COULD NOT DUPLICATE. BOTH ZONE TEMP CONT'S BITE CK GOOD. GVI BOTH AIR COND BAYS WITH PACKS RUNNING - NO DISCREPANCIES NOTED. RAN BOTH PACKS FULL COLD / NML - ALL CKD GOOD. R & RD LEFT PACK TEMP CONT VALVE PRECAUTIONARY PER 21-51-10. OPS CKS NML. GND VERIFICATION SUCCESSFUL, SEAMC JARRED NOTIFIED. REF LOG #60848488 FOR TOP DEFERRAL.