|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0601 To 1200|
|Locale Reference||airport : dtw|
|Altitude||msl bound lower : 1100|
msl bound upper : 1100
|Controlling Facilities||tower : dtw|
|Operator||common carrier : air carrier|
|Make Model Name||Light Transport, High Wing, 2 Turboprop Eng|
|Flight Phase||descent : approach|
|Route In Use||approach : straight in|
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Qualification||pilot : cfi|
pilot : commercial
pilot : instrument
|Experience||flight time last 90 days : 250|
flight time total : 2450
flight time type : 320
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Anomaly||aircraft equipment problem : critical|
|Independent Detector||other flight crewa|
|Resolutory Action||flight crew : overcame equipment problem|
flight crew : declared emergency
|Air Traffic Incident||other|
On short final (500' AGL) power surges were noted in left engine. Torque was oscillating between 0 and 2000'/pounds. The captain immediately shut down left engine (fully feathered by 300' AGL). Mechanics were unable to reproduce problem and sent the propeller governor back for analysis to the mfr. Other company pilots have reported the problem (although with 0-1000'/pound torque oscillations) with other planes. They attributed it to a stuck autofeather arming contact in the power levers (the contact arms the automatic-feather system when the power is advanced). Their theory is that when the power was reduced, the autofeather system remained armed and our engine was cycling in and out of feather. They solved their problems in flight by jockeying the power levers and unsticking the contact. Had there been more communication among pilots our shut down may have been avoided. We may have known about a common problem and its cure. Part of the reluctance of pilots to discuss problems such as this is a paranoia of being violated whenever an incident of any type occurs.
Original NASA ASRS Text
Title: ACR LTT POWER SURGING ON FINAL APCH INFLT ENGINE SHUTDOWN.
Narrative: ON SHORT FINAL (500' AGL) PWR SURGES WERE NOTED IN LEFT ENG. TORQUE WAS OSCILLATING BTWN 0 AND 2000'/LBS. THE CAPT IMMEDIATELY SHUT DOWN LEFT ENG (FULLY FEATHERED BY 300' AGL). MECHS WERE UNABLE TO REPRODUCE PROB AND SENT THE PROP GOVERNOR BACK FOR ANALYSIS TO THE MFR. OTHER COMPANY PLTS HAVE RPTED THE PROB (ALTHOUGH WITH 0-1000'/LB TORQUE OSCILLATIONS) WITH OTHER PLANES. THEY ATTRIBUTED IT TO A STUCK AUTOFEATHER ARMING CONTACT IN THE PWR LEVERS (THE CONTACT ARMS THE AUTO-FEATHER SYS WHEN THE PWR IS ADVANCED). THEIR THEORY IS THAT WHEN THE PWR WAS REDUCED, THE AUTOFEATHER SYS REMAINED ARMED AND OUR ENG WAS CYCLING IN AND OUT OF FEATHER. THEY SOLVED THEIR PROBS IN FLT BY JOCKEYING THE PWR LEVERS AND UNSTICKING THE CONTACT. HAD THERE BEEN MORE COM AMONG PLTS OUR SHUT DOWN MAY HAVE BEEN AVOIDED. WE MAY HAVE KNOWN ABOUT A COMMON PROB AND ITS CURE. PART OF THE RELUCTANCE OF PLTS TO DISCUSS PROBS SUCH AS THIS IS A PARANOIA OF BEING VIOLATED WHENEVER AN INCIDENT OF ANY TYPE OCCURS.
Data retrieved from NASA's ASRS site as of August 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.