Date: 201412
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: B747 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Pneumatic Valve/Bleed Valve
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Communication Breakdown; Situational Awareness
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Human Factors; MEL; Procedure; Aircraft
Primary problem: Human Factors

Narrative: Reviewing the maintenance logs and history in flight ops prior to signing off the flight plan. I; and the rest of my crew; noticed the strange deferral for a Number 3 engine bleed light inop. It caught our attention since it was stated there were no engine run qualified mechanics in Airport ZZZ; to check what I can only guess would be to insure that the bleed is working properly. Arriving at the airplane the old Maintenance Release was found on the flight deck. It shed more light on this situation by describing the departure from Airport ZZZZ on the last flight with an inop bleed valve. And in that log the exact same wording of: no run qualified mechanics available; which is believable in Airport ZZZZ. In addition; the fuel logs for the arrival and time on the ground in Airport ZZZ were in the flight deck. The only fuel accounted for was APU burn and some defueling that took place. It was at this time I was gravely concerned about the maintenance status of the airplane regarding the Number 3 engine bleed air. At this point maintenance had issued the Maintenance Release showing a deferred Number 3 engine bleed light 'only' inop. I asked the mechanic that was on the flight deck how it was determined the bleed was working; since it was inop on the inbound flight. He called that question in to the Maintenance Control and I heard the reply on his radio that an engine run was accomplished.I referred the mechanic to the deferral and it stated no engine run was accomplished. The person on the other end of the radio insisted an engine run was done to verify the bleed worked. A new Maintenance Release was generated and even though I was not totally comfortable with the situation; I accepted the airplane based on what maintenance stated regarding the working Number 3 engine bleed air system. Taxing out to runway 28L I decided to isolate the Number 3 bleed air system and verify it was working normally as we were dispatched. The bleed system for Number 3 was not working. This was not really a surprise to me; but I was amazed the maintenance structure at our Air Carrier X would lie so blatantly. We advised the situation to the Maintenance Controller and they advised us to return to the gate immediately. At the gate; a mechanic supervisor came to the flight deck to confer with us. Once he understood what had just happened he was as surprised as myself. The proper deferral was put in place with the mechanics closing the Pressure Regulating Shut Off Valve (PRSOV) after Engine 3 start. I normally try to just state the facts in this report but I feel that it is important to say that in my extensive career at Air Carrier X and other airlines; it is this flagrant disregard for FARs and Company procedures that safety will be compromised to the point of a hull loss. This airplane was on the ground in Airport ZZZ for over a day. Why during that time was no attention given to this situation. The bleed valve was deferred inoperative on arrival. I can only guess; but I would say it was forgotten; and a deferral was fabricated about the bleed light based on lies. It was an incredible inconvenience to our customers to have to return to the gate and delay the flight more than two hours. If we had gotten airborne and found this out I would have diverted. Another thing this clearly points out is that the PIC does not have enough information with our electronic logbook to verify the mechanical airworthiness of the airplane. I had to guess and read between the lines in an attempt to figure out whether this airplane was airworthy for flight. At the gate.




Synopsis: A Captain reports on a lengthy discussion with Maintenance Control about contradictory statements regarding the status of a continuing MEL for Number 3 Engine bleed valve light deferred as inoperative on a B747 aircraft. Maintenance said the engine had been run and the bleed valve worked; not the light. On taxi-out; the Number 3 Engine PSROV (Pressure Regulating Shut Off Valve) failed to operate; requiring a return to gate. No engine run had actually been performed. Captain raises issue of FARs and company procedures being ignored.