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ATA 28 Fuel
1 - Fuel quantity indicating system T/S microguide. 737-3/4/500
2 - Boostpump bonding jumper corrosion. 737-6/7/8/900
3 - Pump removal valve stuck closed and wont open. 737-3/4/500
4 - Fuse "Fuel control 1 Fwd, 2 Aft, Ctr right" trips out. 737-3/4/500
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1 - Fuel quantity
indicating system T/S microguide. 737-3/4/500
2 - Boostpump bonding jumper corrosion.
737-6/7/8/900
Hello, we have serious finding when we did the inspection on B737NG wing front spar - it is corrosion under fuel boost pumps bonding jumpers. You can discover the corrosion by cracked paint and swollen surface around the bonding jumper connection. Also cracks in the sealant are an indication of corrosion underneath. What work is needed for example: Removal of the boostpumps, rework of the corroded area, tank-entry, replacement of the bonding-jumpers brackets, bonding jumper protection against corrosion etc. UPDATE: I have a picture when repair has been done - boeing directed us to made a doubler over damaged area. Doubler has been attached to the wing front spar web by several Hi-locks as wieved on the last picture. A total repair time of several days is not abnormal. More info from enclosed pictures. Thanks to Josef for his input.
3 -
Pump
removal valve stuck closed and wont open.
737-3/4/500
After replacment of fwd main tank fuel booster pump , pump removal valve stuck closed and wont open. But if you remove back the pump and and tap the valve slowly and at the same time move the valve handel open , valve will do open and save you from grounding the aircraft for fuel tank entry to replace the valve. Thanks to M Mustafa.
4 -
Fuse "Fuel control 1 Fwd, 2 Aft, Ctr right" trips out. 737-3/4/500
We had an unexplained trip out of this circuitbreaker when we turn off both center boost pumps. All 3 control relays were OK (tank 1 fwd boost pump relay, tank 2 aft boost pump relay and right center boost pump relay), they are behind copilot CB panel. At the end we found a defective "scavenge fuel shut off valve" who is energized across a 20 minute timer in engine accessory unit module from this same CB! Thanks to Viktor for this input.