Engine flameout when thrust levers reduced for descent. Engine restarted at a lower altitude.

Attributes
ACN	83069
Time
Date	198803
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : jnc
State Reference	CO
Altitude	msl bound lower : 29000 msl bound upper : 41000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdv
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 125 flight time total : 10000 flight time type : 1500
ASRS Report	83069
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 30 flight time total : 12000 flight time type : 1200
ASRS Report	83215
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance flight crew : overcame equipment problem
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

After receiving reports of moderate turbulence and wave activity at FL410 that was near our flight track and a sudden rise of OAT 526.49 degree we decided to descend to FL370. An automatic descent was made to FL370. As the aircraft started a slow nose down pitch and the throttles slowly retarded I felt and heard a loud compressor stall (backfire). I noticed that the #2 engine EPR fluctuating slightly. I disconnected the autopilot and autothrottle and as the power was increased to maintain .80 the #2 engine indication remained fixed and the aircraft was in a yaw. I can not recall the exact egt temperature but it was not in the yellow or red range on the EICAS. I called for the engine failure checklist and to select the engine out altitude on the FMC. The captain selected the information from the FMC and requested descent to FL290 which we received. During the descent the engine failure check list was completed. We elected to restart the #2 engine because we felt there was no damage to the engine and there has been past reports of this problem with other widebody transport. Also there is a procedure in our handbook for an engine steady state stall condition 1) close throttle, fuel contact switch off, engine flight start. The first attempt to start the #2 engine was unsuccessful. No engine temperature rise after 20 second. I checked again our airspeed and the start envelope displayed on the EICAS screens and we were well above the requirements. The second attempt was a cross bleed start was successful. All #2 engine indications were normal. Ie, egt, F/F, vig, ect. The captain decided to climb back to cruising altitude and to continue to our destination. Callback conversation with reporter revealed the following information. Company is modifying bleed valve to open at a different time. They also have changed the procedure for beginning ascent. Autothrottles are off and cpr is reduced to 1.2 until the engine stabilizes the flight idle is set. Reporter had no problem in restarting the engine once they had stabilized at the lower altitude.

Original NASA ASRS Text

Title: ENGINE FLAMEOUT WHEN THRUST LEVERS REDUCED FOR DESCENT. ENGINE RESTARTED AT A LOWER ALT.

Narrative: AFTER RECEIVING REPORTS OF MODERATE TURBULENCE AND WAVE ACTIVITY AT FL410 THAT WAS NEAR OUR FLT TRACK AND A SUDDEN RISE OF OAT 526.49 DEG WE DECIDED TO DESCEND TO FL370. AN AUTO DESCENT WAS MADE TO FL370. AS THE ACFT STARTED A SLOW NOSE DOWN PITCH AND THE THROTTLES SLOWLY RETARDED I FELT AND HEARD A LOUD COMPRESSOR STALL (BACKFIRE). I NOTICED THAT THE #2 ENG EPR FLUCTUATING SLIGHTLY. I DISCONNECTED THE AUTOPILOT AND AUTOTHROTTLE AND AS THE POWER WAS INCREASED TO MAINTAIN .80 THE #2 ENG INDICATION REMAINED FIXED AND THE ACFT WAS IN A YAW. I CAN NOT RECALL THE EXACT EGT TEMP BUT IT WAS NOT IN THE YELLOW OR RED RANGE ON THE EICAS. I CALLED FOR THE ENG FAILURE CHECKLIST AND TO SELECT THE ENG OUT ALT ON THE FMC. THE CAPT SELECTED THE INFO FROM THE FMC AND REQUESTED DESCENT TO FL290 WHICH WE RECEIVED. DURING THE DESCENT THE ENG FAILURE CHECK LIST WAS COMPLETED. WE ELECTED TO RESTART THE #2 ENG BECAUSE WE FELT THERE WAS NO DAMAGE TO THE ENG AND THERE HAS BEEN PAST REPORTS OF THIS PROBLEM WITH OTHER WDB. ALSO THERE IS A PROCEDURE IN OUR HANDBOOK FOR AN ENG STEADY STATE STALL CONDITION 1) CLOSE THROTTLE, FUEL CONTACT SWITCH OFF, ENG FLT START. THE FIRST ATTEMPT TO START THE #2 ENG WAS UNSUCCESSFUL. NO ENG TEMP RISE AFTER 20 SEC. I CHECKED AGAIN OUR AIRSPEED AND THE START ENVELOPE DISPLAYED ON THE EICAS SCREENS AND WE WERE WELL ABOVE THE REQUIREMENTS. THE SECOND ATTEMPT WAS A CROSS BLEED START WAS SUCCESSFUL. ALL #2 ENG INDICATIONS WERE NORMAL. IE, EGT, F/F, VIG, ECT. THE CAPT DECIDED TO CLIMB BACK TO CRUISING ALT AND TO CONTINUE TO OUR DEST. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. COMPANY IS MODIFYING BLEED VALVE TO OPEN AT A DIFFERENT TIME. THEY ALSO HAVE CHANGED THE PROC FOR BEGINNING ASCENT. AUTOTHROTTLES ARE OFF AND CPR IS REDUCED TO 1.2 UNTIL THE ENG STABILIZES THE FLT IDLE IS SET. RPTR HAD NO PROB IN RESTARTING THE ENG ONCE THEY HAD STABILIZED AT THE LOWER ALT.

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.