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A B757 crew diverts to an enroute airport after the engine EPR; N1; N2 and egt continuously hunt in flight indicating possible fuel control problem.
| Attributes | |
| ACN | 814083 |
| Time | |
| Date | 200811 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | msl single value : 34000 |
| Aircraft 1 | |
| Controlling Facilities | artcc : zzz.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Experience | flight time last 90 days : 100 flight time total : 11000 flight time type : 5000 |
| ASRS Report | 814083 |
| Events | |
| Anomaly | aircraft equipment problem : less severe |
| Independent Detector | aircraft equipment other aircraft equipment : engine instruments other flight crewa |
| Resolutory Action | flight crew : diverted to alternate |
| Consequence | other |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
The log history of this aircraft showed a write-up for 'in cruise left engine EPR hunts; as well as N1 and egt; with N2 stable and 85 ff.' this was signed off by maintenance. Takeoff was busy with a flaps 15 degree setting; much turbulence and IFR conditions. The first officer reported that no unusual fluctuations were observed in the takeoff roll. At cruise; we observed the same hunting characteristics as previously reported. No other symptoms were present; no duct pressure changes; no unusual sounds; no vibration; etc. As the flight progressed; we discussed the symptoms and consulted our manuals. It was then decided to talk to dispatch as well as maintenance. Maintenance thought it might be a fuel controller problem. We talked to dispatch about a possible precautionary landing. As time went on; N2 indications began to slightly hunt on that engine; and the fuel flow began to go up. Still no other symptoms; however; we decided that a landing in ZZZ would be the best course. A rerte to ZZZ was arranged with dispatch and ATC. We discussed the possibility of a problem with the engine in the descent and turned on igniters and the APU. Landing was uneventful. We were redispatched in another aircraft.
Original NASA ASRS Text
Title: A B757 CREW DIVERTS TO AN ENROUTE AIRPORT AFTER THE ENGINE EPR; N1; N2 AND EGT CONTINUOUSLY HUNT IN FLIGHT INDICATING POSSIBLE FUEL CONTROL PROBLEM.
Narrative: THE LOG HISTORY OF THIS ACFT SHOWED A WRITE-UP FOR 'IN CRUISE L ENG EPR HUNTS; AS WELL AS N1 AND EGT; WITH N2 STABLE AND 85 FF.' THIS WAS SIGNED OFF BY MAINT. TKOF WAS BUSY WITH A FLAPS 15 DEG SETTING; MUCH TURB AND IFR CONDITIONS. THE FO RPTED THAT NO UNUSUAL FLUCTUATIONS WERE OBSERVED IN THE TKOF ROLL. AT CRUISE; WE OBSERVED THE SAME HUNTING CHARACTERISTICS AS PREVIOUSLY RPTED. NO OTHER SYMPTOMS WERE PRESENT; NO DUCT PRESSURE CHANGES; NO UNUSUAL SOUNDS; NO VIBRATION; ETC. AS THE FLT PROGRESSED; WE DISCUSSED THE SYMPTOMS AND CONSULTED OUR MANUALS. IT WAS THEN DECIDED TO TALK TO DISPATCH AS WELL AS MAINT. MAINT THOUGHT IT MIGHT BE A FUEL CONTROLLER PROB. WE TALKED TO DISPATCH ABOUT A POSSIBLE PRECAUTIONARY LNDG. AS TIME WENT ON; N2 INDICATIONS BEGAN TO SLIGHTLY HUNT ON THAT ENG; AND THE FUEL FLOW BEGAN TO GO UP. STILL NO OTHER SYMPTOMS; HOWEVER; WE DECIDED THAT A LNDG IN ZZZ WOULD BE THE BEST COURSE. A RERTE TO ZZZ WAS ARRANGED WITH DISPATCH AND ATC. WE DISCUSSED THE POSSIBILITY OF A PROB WITH THE ENG IN THE DSCNT AND TURNED ON IGNITERS AND THE APU. LNDG WAS UNEVENTFUL. WE WERE REDISPATCHED IN ANOTHER ACFT.
Data retrieved from NASA's ASRS site as of May 2009 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.