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Medium large transport aircraft in cruise at FL330 had vibration. Shut down #1 engine. Restarted engine and determined APU was source of vibration.
| Attributes | |
| ACN | 152523 |
| Time | |
| Date | 199007 |
| Day | Mon |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : fim airport : lax |
| State Reference | CA |
| Altitude | msl bound lower : 33000 msl bound upper : 33000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla tracon : ict |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other descent other landing other |
| Route In Use | enroute airway : zla |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : atp pilot : instrument pilot : commercial |
| Experience | flight time last 90 days : 210 flight time total : 19000 flight time type : 5400 |
| ASRS Report | 152523 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : commercial pilot : instrument |
| Events | |
| Anomaly | aircraft equipment problem : less severe |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
About 5 mins after level off at FL330 50 mi north of filmore VOR en route from sfo to lax, a vibration was felt. The F/a's called asking if we heard the noise and vibration. The only indication in the cockpit was the #1 fuel flow which was fluctuating +/-500 #/hour. The throttle was retarded and the fuel flow and vibration continued. A lower altitude was requested and FL20 was given. The vibration increased slightly, so a precautionary engine shutdown checklist was performed. FL240 was requested. On the engine shutdown check the APU generator would not take the engine buss. Upon checking the APU the frequency meter was pegging out on both ends. It was determined that the APU was the problem. The aircraft lights had been steady with no dimming. The #1 engine was restarted and the APU was shutdown. The #1 gen took the buss and flight proceeded to lax, the nearest suitable airport. At the gate the aircraft would not accept the external power. After the passenger and all deplaned the total electrical system was shutdown.
Original NASA ASRS Text
Title: MLG ACFT IN CRUISE AT FL330 HAD VIBRATION. SHUT DOWN #1 ENGINE. RESTARTED ENGINE AND DETERMINED APU WAS SOURCE OF VIBRATION.
Narrative: ABOUT 5 MINS AFTER LEVEL OFF AT FL330 50 MI N OF FILMORE VOR ENRTE FROM SFO TO LAX, A VIBRATION WAS FELT. THE F/A'S CALLED ASKING IF WE HEARD THE NOISE AND VIBRATION. THE ONLY INDICATION IN THE COCKPIT WAS THE #1 FUEL FLOW WHICH WAS FLUCTUATING +/-500 #/HR. THE THROTTLE WAS RETARDED AND THE FUEL FLOW AND VIBRATION CONTINUED. A LOWER ALT WAS REQUESTED AND FL20 WAS GIVEN. THE VIBRATION INCREASED SLIGHTLY, SO A PRECAUTIONARY ENG SHUTDOWN CHKLIST WAS PERFORMED. FL240 WAS REQUESTED. ON THE ENG SHUTDOWN CHK THE APU GENERATOR WOULD NOT TAKE THE ENG BUSS. UPON CHKING THE APU THE FREQ METER WAS PEGGING OUT ON BOTH ENDS. IT WAS DETERMINED THAT THE APU WAS THE PROB. THE ACFT LIGHTS HAD BEEN STEADY WITH NO DIMMING. THE #1 ENG WAS RESTARTED AND THE APU WAS SHUTDOWN. THE #1 GEN TOOK THE BUSS AND FLT PROCEEDED TO LAX, THE NEAREST SUITABLE ARPT. AT THE GATE THE ACFT WOULD NOT ACCEPT THE EXTERNAL PWR. AFTER THE PAX AND ALL DEPLANED THE TOTAL ELECTRICAL SYS WAS SHUTDOWN.
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.