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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Air carrier large transport experiences failure of magnetic compass systems after takeoff, checks and finds flight legal to continue if in VMC. Flight continues, but destination WX deteriorates leading to deviation. Prolonged vectoring and deviation lead to low fuel state, and flight crew declares emergency.
| Attributes | |
| ACN | 143610 |
| Time | |
| Date | 199004 |
| Day | Sun |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : cha |
| State Reference | TN |
| Altitude | msl bound lower : 11000 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : ztl |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | cruise other landing other other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : commercial pilot : atp pilot : cfi pilot : flight engineer |
| Experience | flight time last 90 days : 200 flight time total : 16000 flight time type : 600 |
| ASRS Report | 143610 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 160 flight time total : 7000 flight time type : 3000 |
| ASRS Report | 143611 |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : declared emergency other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
Narrative:
After takeoff from phoenix, both magnetic compass systems began to precess. We informed departure control of our difficulty and continued our climb in order to assess our problem in a safer environment. We quickly determined that we could navigate safely using our vors and by updating our magnetic compasses with reference to the standby compass. We received confirmation from our company flight control that we were safe and legal to continue to our destination, atlanta, provided we remained in visual conditions. We were able to alter our route and stay visual but as we approached the atlanta area the WX deteriorated. We requested a vector to our alternate (knoxville). Instead of a direct route we were given several vectors and held down to 11000'. Due to our reduced reserve fuel from circumnaving enroute WX we declared an emergency to receive priority handling. To further improve our fuel situation we diverted to chattanooga since it was clearer and closer.
Original NASA ASRS Text
Title: ACR LGT EXPERIENCES FAILURE OF MAGNETIC COMPASS SYSTEMS AFTER TKOF, CHECKS AND FINDS FLT LEGAL TO CONTINUE IF IN VMC. FLT CONTINUES, BUT DESTINATION WX DETERIORATES LEADING TO DEVIATION. PROLONGED VECTORING AND DEVIATION LEAD TO LOW FUEL STATE, AND FLT CREW DECLARES EMERGENCY.
Narrative: AFTER TKOF FROM PHOENIX, BOTH MAGNETIC COMPASS SYSTEMS BEGAN TO PRECESS. WE INFORMED DEP CTL OF OUR DIFFICULTY AND CONTINUED OUR CLIMB IN ORDER TO ASSESS OUR PROBLEM IN A SAFER ENVIRONMENT. WE QUICKLY DETERMINED THAT WE COULD NAVIGATE SAFELY USING OUR VORS AND BY UPDATING OUR MAGNETIC COMPASSES WITH REFERENCE TO THE STANDBY COMPASS. WE RECEIVED CONFIRMATION FROM OUR COMPANY FLT CTL THAT WE WERE SAFE AND LEGAL TO CONTINUE TO OUR DEST, ATLANTA, PROVIDED WE REMAINED IN VISUAL CONDITIONS. WE WERE ABLE TO ALTER OUR ROUTE AND STAY VISUAL BUT AS WE APCHED THE ATLANTA AREA THE WX DETERIORATED. WE REQUESTED A VECTOR TO OUR ALTERNATE (KNOXVILLE). INSTEAD OF A DIRECT ROUTE WE WERE GIVEN SEVERAL VECTORS AND HELD DOWN TO 11000'. DUE TO OUR REDUCED RESERVE FUEL FROM CIRCUMNAVING ENROUTE WX WE DECLARED AN EMER TO RECEIVE PRIORITY HANDLING. TO FURTHER IMPROVE OUR FUEL SITUATION WE DIVERTED TO CHATTANOOGA SINCE IT WAS CLEARER AND CLOSER.
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.