Narrative:

At cruise altitude, we found ourselves mistakenly on a suction feed operation of engines #1 and #3. Normally this is not a problem on a B727, however, the particular model B727 we operate, this can potentially cause a flameout. This problem is known to the operator and we have interim operating procedures until a permanent fix is approved. We elected to run a procedure in our checklists in order to restore boosted fuel pressure. As we were running this checklist which includes idling back each engine one at a time in order to restore boost pumps, we did notice some erratic EPR and fuel flow indications for several seconds, and then normal operation took place for remainder of the flight and descent and landing uneventfully. Throughout running this procedure normal RPM was maintained as well as normal generator and pressurization loads on all engines. Although I thought this event did not meet any required reporting to various agencies, since this is a known problem, I will state that once suction feed exists, it is imperative to quickly restore boosted fuel pressure as soon as possible to prevent a potential engine flameout condition! Callback conversation with reporter revealed the following information: the reporter stated the aircraft was a B727-100QF equipped with rolls royce tay 651 engines. The reporter said a problem with this engine has occurred several times and resulted in engine flameout. The reporter said this engine will not suction feed fuel using only the engine driven fuel pump. The reporter said an interim procedure has been implemented to avoid this problem. The reporter stated in this incident all 3 engines remained operating but did notice erratic EPR and fuel flow indications.

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Original NASA ASRS Text

Title: A B727-100QF IN CRUISE AT FL330 INADVERTENTLY HAD ENGS #1 AND #3 OPERATING ON SUCTION FEED. RAN PROC TO RESTORE BOOSTED FEED AND NOTED ERRATIC ENG PRESSURE RATIO AND FUEL FLOW INDICATIONS FOR SEVERAL SECONDS.

Narrative: AT CRUISE ALT, WE FOUND OURSELVES MISTAKENLY ON A SUCTION FEED OP OF ENGS #1 AND #3. NORMALLY THIS IS NOT A PROB ON A B727, HOWEVER, THE PARTICULAR MODEL B727 WE OPERATE, THIS CAN POTENTIALLY CAUSE A FLAMEOUT. THIS PROB IS KNOWN TO THE OPERATOR AND WE HAVE INTERIM OPERATING PROCS UNTIL A PERMANENT FIX IS APPROVED. WE ELECTED TO RUN A PROC IN OUR CHKLISTS IN ORDER TO RESTORE BOOSTED FUEL PRESSURE. AS WE WERE RUNNING THIS CHKLIST WHICH INCLUDES IDLING BACK EACH ENG ONE AT A TIME IN ORDER TO RESTORE BOOST PUMPS, WE DID NOTICE SOME ERRATIC EPR AND FUEL FLOW INDICATIONS FOR SEVERAL SECONDS, AND THEN NORMAL OP TOOK PLACE FOR REMAINDER OF THE FLT AND DSCNT AND LNDG UNEVENTFULLY. THROUGHOUT RUNNING THIS PROC NORMAL RPM WAS MAINTAINED AS WELL AS NORMAL GENERATOR AND PRESSURIZATION LOADS ON ALL ENGS. ALTHOUGH I THOUGHT THIS EVENT DID NOT MEET ANY REQUIRED RPTING TO VARIOUS AGENCIES, SINCE THIS IS A KNOWN PROB, I WILL STATE THAT ONCE SUCTION FEED EXISTS, IT IS IMPERATIVE TO QUICKLY RESTORE BOOSTED FUEL PRESSURE ASAP TO PREVENT A POTENTIAL ENG FLAMEOUT CONDITION! CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A B727-100QF EQUIPPED WITH ROLLS ROYCE TAY 651 ENGS. THE RPTR SAID A PROB WITH THIS ENG HAS OCCURRED SEVERAL TIMES AND RESULTED IN ENG FLAMEOUT. THE RPTR SAID THIS ENG WILL NOT SUCTION FEED FUEL USING ONLY THE ENG DRIVEN FUEL PUMP. THE RPTR SAID AN INTERIM PROC HAS BEEN IMPLEMENTED TO AVOID THIS PROB. THE RPTR STATED IN THIS INCIDENT ALL 3 ENGS REMAINED OPERATING BUT DID NOTICE ERRATIC EPR AND FUEL FLOW INDICATIONS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.