Service difficulty report · Modulating Valve · Boeing 757224

Difficulty date
May 13, 2025
Submitted
May 15, 2025
Operation
Air carrier
Aircraft
N58101
Make and model
Boeing 757224
Aircraft serial
27291
Aircraft time
116,008 hours, 24,960 cycles
Part
Modulating Valve
Part number
3987865
Part serial
5332
Condition
Faulted
Location
Zone 100
Part time
105,692 hours, 23,107 cycles
Stage of operation
CL
How discovered
O
Nature of condition
J
Precautionary procedure
A

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

What was found

FLT DECK VERY WARM AFTER TAKEOFF QRH PROCD NO HELPFLIGHT CREW REPORTS NO AIR FLOW FROM GASPER VENTS, NO ADVISORY MSG OR EICAS MSGS. NO DIFFERENCE IN AIR FLOW REGARDLESS OF FLIGHT PHASE. CBS OPENED REF AMM 25-13-03 GLARESHIELD REMOVAL. CHECKED DUCTING BEHIND PANEL P1-3 AND P3-1. FOUND NO LEAKS OR CUTS IN DUCTING. CBS CLOSED REF AMM 25-13-03 AND GLARESHIELD CLOSE UP. BITE CHECKED BOTH LEFT, RIGHT, AND STANDBY PTC PER AMM TASK 21-51-14-745-001. ALL BOXES CHECKED GOOD. NO FAULTS FOUND. FURTHER TROUBLESHOOTING REQUIRD. REMOVED AND REPLACED FLIGHT DECK TRIM AIR MODULATING VALVE IAW AMM 21-61-07. OPS CHECK GOOD. CANNOT DUPLICATE FAULT REQUIRES ENGINE BLEED TO DUPLICATE FAULT OBSERVED BY PILOTS. FOUND FWD CAB INOP LIGHT ON WITH FWD CABIN TEMP EICAS MSG REF FIM 21-60 FAULT TREE 804 NO FAULTS ON ZONE TEMP CONTROL UNIT OR LEFT/RIGHT PACK TEMP CONTROL UNIT FOLLOWED FIM 21-60 FAULT TREE 804, REPLACED RELAY K10363 FWD ZONE INOP RELAY & K10312 FWD ZONE AUTO/OFF RELAY. OPS CHECK GOOD. NO OTHER FAFLT COMPT ZONE TRIM AIR MODULATING VALVE REPLACED AND REPLACED PER AMM 21-61-07-004-030. OPS CHECK GOOD.