Flight crew of air carrier mdt declared an emergency and returned to land after failure of 1 engine.

Attributes
ACN	272719
Time
Date	199405
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : hsv
State Reference	AL
Altitude	msl bound lower : 12000 msl bound upper : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Route In Use	enroute airway : zme
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : cfi
Experience	flight time last 90 days : 200 flight time total : 6000 flight time type : 400
ASRS Report	272719
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	other other : other pilot : atp pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : declared emergency other
Consequence	faa : investigated Other
Supplementary
Primary Problem	Aircraft

Narrative:

Coming into hsv on prior leg, the right engine N1 gauge began to fluctuate plus or minus 20 percent. On the ground, called maintenance control and made entry into logbook. All other engine indications were normal. Since all other parameters were normal, we agreed to defer the gauge per the MEL. Next leg -- start, taxi, takeoff were all normal and all engine parameters were normal, including the right engine N1. At about 12000 ft, there was a loud bang followed by a total failure of the right engine. We secured the engine, declared an emergency, and returned to hsv and landed without further incident. It seems that the fluctuating N1 was not a bad gauge but a sign that the engine was going bad even though fuel flow, torque and itt were all normal. The MEL allowed the gauge to be deferred without a mechanic trouble- shooting it. The N1 is the only engine gauge that can be deferred in our MEL. Had a mechanic come out and swapped gauges and run the engine up, an in-flight engine shutdown might have been avoided. I should have insisted on a mechanic coming out also. Incidentally, the first officer is also typed in the aircraft and is also a mechanic with ia authority/authorized, and he also believed it was a bad N1 gauge given the information we had.

Original NASA ASRS Text

Title: FLC OF ACR MDT DECLARED AN EMER AND RETURNED TO LAND AFTER FAILURE OF 1 ENG.

Narrative: COMING INTO HSV ON PRIOR LEG, THE R ENG N1 GAUGE BEGAN TO FLUCTUATE PLUS OR MINUS 20 PERCENT. ON THE GND, CALLED MAINT CTL AND MADE ENTRY INTO LOGBOOK. ALL OTHER ENG INDICATIONS WERE NORMAL. SINCE ALL OTHER PARAMETERS WERE NORMAL, WE AGREED TO DEFER THE GAUGE PER THE MEL. NEXT LEG -- START, TAXI, TKOF WERE ALL NORMAL AND ALL ENG PARAMETERS WERE NORMAL, INCLUDING THE R ENG N1. AT ABOUT 12000 FT, THERE WAS A LOUD BANG FOLLOWED BY A TOTAL FAILURE OF THE R ENG. WE SECURED THE ENG, DECLARED AN EMER, AND RETURNED TO HSV AND LANDED WITHOUT FURTHER INCIDENT. IT SEEMS THAT THE FLUCTUATING N1 WAS NOT A BAD GAUGE BUT A SIGN THAT THE ENG WAS GOING BAD EVEN THOUGH FUEL FLOW, TORQUE AND ITT WERE ALL NORMAL. THE MEL ALLOWED THE GAUGE TO BE DEFERRED WITHOUT A MECH TROUBLE- SHOOTING IT. THE N1 IS THE ONLY ENG GAUGE THAT CAN BE DEFERRED IN OUR MEL. HAD A MECH COME OUT AND SWAPPED GAUGES AND RUN THE ENG UP, AN INFLT ENG SHUTDOWN MIGHT HAVE BEEN AVOIDED. I SHOULD HAVE INSISTED ON A MECH COMING OUT ALSO. INCIDENTALLY, THE FO IS ALSO TYPED IN THE ACFT AND IS ALSO A MECH WITH IA AUTH, AND HE ALSO BELIEVED IT WAS A BAD N1 GAUGE GIVEN THE INFO WE HAD.

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.