Maintenance Airframe; Maintenance Avionics; Maintenance Powerplant
Maintenance Technician 36
Workload; Troubleshooting; Distraction; Communication Breakdown; Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance
General Maintenance Action
Procedure; Logbook Entry; Human Factors
I; as Technician X; was made aware that the absence of proper documentation regarding the cracking of the APU fuel line is being reviewed for possible non-conformance of FAA and Air Carrier X's Maintenance Policy. This was a surprise to me as I knew what caused the APU shutdown and it was no fault of the APU. I had assumed cracking a fuel line to bleed air following a fuel starvation event to be the same category as resetting a Circuit Breaker (C/B) to restore normal system operation. The following is to the best of my recollection regarding the low fuel issue on Flight XXXX; MD-88 aircraft that occurred July of this year.  For the technicians (techs) working out of F-2; we generally assign one tech to each 3-gate set; and then we generally assign one floater to assist as needed with all 9-gates in our work area. I was working as a floater that day and Technician Y was assigned to three gates. A call came in over the radio regarding a low fuel situation on Technician Y's gates; so I went out to assist Tech Y on the call. Tech Y proceeded to the cockpit to check with the Flight crew and I went straight to the fueling panel. When I arrived at the fueling panel; the fuel hose was already hooked up. I checked the wing fuel gauges and noted approximately 1000 lbs. of fuel in each wing and approximately 6;000 lbs. of fuel in the center tank.I understood that the APU [did an] auto-shutdown due to low fuel shortly after the crew started it. Technician Y and I decided to bleed the APU fuel line in an attempt to get the APU started. Technician Y went to the APU compartment to crack the fuel line while I went to the cockpit to turn on the fuel pump. After bleeding the fuel line; the APU was started without any further issues. Both engines were also started and run at idle power while at the gate. The Flight crew also expressed concern with the way their fuel boost pump low pressure lights were checking out. The lights were taking a full two minutes to come on after the fuel pumps were turned off. I explained to the crew that it was just a tight system and the lights would come on once the pressure in the lines decayed. MD-88 Aircraft Maintenance Manual (AMM) 73-33 PB-20-I; Paragraph-4 states that it can take approximately two minutes for the lights to come on. On this aircraft; the lights did take a full two minutes to come on after the pumps were shut off. The captain was also concerned about the left engine fuel flow indicator showing 480 with the engine shut down. He originally thought that indication was 'pressure' rather than 'flow' and felt that might be why his fuel boost pump low-pressure lights took so long to come during his test. I explained that there was no correlation between the measurements of flow and pressure and I then placed the left engine fuel flow on MEL 73-00-01B. To help prevent similar situations regarding the proper documentation of maintenance from occurring in the future; I believe AMT's should be provided with an improved definition of just what constitutes 'documentable maintenance.'  While some items such as changing a hydraulic pump; fuel pump; tire; etc. are clearly maintenance and; as such; need to be documented in the logbook; other items are so minor in nature that I question the need for documentation. The lack of clarity for me lie in defining lesser events such as reseating a lower sidewall grill in the cabin of a B-757 or reseating an in-seat video monitor trim bezel (both daily events); or tightening a loose screw on a galley lock. I believed cracking of the fuel line on a fully functional APU fell into this latter category and did not need to be documented in the logbook. I now understand that I was in error and that I should have documented my actions.
I; Technician Y; was not aware that a log book entry was not accomplished by the flight crew. I met the FO and captain in the jetway at the time the passengers were deplaning so there was a lot of noise from ground equipment and passengers deplaning. What I thought I heard them say was' I think we [screwed] up'; they went on to say some more stuff but all I could make out what they said was the APU shut down or would not start. I told my partner Technician X that I would go and bleed the APU fuel line to see if that would help [and for] him to turn the fuel pump on [in the cockpit] and I will call on the radio with my findings. I was able to get the APU started after bleeding the air from the fuel line. I was outside most of the time and it was very busy so I am not sure if I was involved in the engine run. I was also helping out at another gate at the time.
Two Line Aircraft Maintenance Technicians (AMTs) report about the lack of proper documentation of maintenance work they performed after cracking an APU fuel line to bleed air from the APU fuel system on an MD-88 aircraft. Flight crew had verbally informed technicians about the APU Auto-Shutdown; but failed to enter discrepancy in their logbook. APU fuel starvation.