A DC9-30 on initial climb declared an emergency and diverted due to a left engine fire warning cause...

Attributes
ACN	380173
Time
Date	199709
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : lga
State Reference	NY
Altitude	agl bound lower : 1000 agl bound upper : 1000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : initial other other
Route In Use	departure other departure sid : sid
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : private pilot : commercial pilot : atp
Experience	flight time last 90 days : 230 flight time total : 7700 flight time type : 1500
ASRS Report	380173
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
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	Other
Supplementary
Primary Problem	Aircraft

Narrative:

After departing runway 4 at lga after gear up and passing 1000 ft AGL, left engine (and fire bell) and fire light illuminated. I and captain verified fire indication with both a and B loops illuminated. Emergency checklist accomplished. After retarding left throttle to idle (part of emergency procedure) fire indications ceased. Declared emergency and requested vectors back to lga for full stop landing. Flight attendants notified of nature of emergency. Uneventful approach and landing (flaps 25 degrees) to runway 4 at lga. Upon clearing runway fire rescue met us and requested us to shut down left engine to inspect. No problems with engine found. Had to be towed back to air carrier gate. (Aircraft would not taxi at that weight, 97800 pounds on 1 engine.) not sure what caused the problem, but due to all fire indications going out after retarding throttle to idle, would suspect bleed air leak. (We tested fire detection system after lights went out and got a good check.) upon talking with lga air carrier maintenance at lga, they suspected a bleed air leak as well, though we never found out with maintenance as to final determination.

Original NASA ASRS Text

Title: A DC9-30 ON INITIAL CLB DECLARED AN EMER AND DIVERTED DUE TO A L ENG FIRE WARNING CAUSED BY AN ENG PNEUMATIC LEAK.

Narrative: AFTER DEPARTING RWY 4 AT LGA AFTER GEAR UP AND PASSING 1000 FT AGL, L ENG (AND FIRE BELL) AND FIRE LIGHT ILLUMINATED. I AND CAPT VERIFIED FIRE INDICATION WITH BOTH A AND B LOOPS ILLUMINATED. EMER CHKLIST ACCOMPLISHED. AFTER RETARDING L THROTTLE TO IDLE (PART OF EMER PROC) FIRE INDICATIONS CEASED. DECLARED EMER AND REQUESTED VECTORS BACK TO LGA FOR FULL STOP LNDG. FLT ATTENDANTS NOTIFIED OF NATURE OF EMER. UNEVENTFUL APCH AND LNDG (FLAPS 25 DEGS) TO RWY 4 AT LGA. UPON CLRING RWY FIRE RESCUE MET US AND REQUESTED US TO SHUT DOWN L ENG TO INSPECT. NO PROBS WITH ENG FOUND. HAD TO BE TOWED BACK TO ACR GATE. (ACFT WOULD NOT TAXI AT THAT WT, 97800 LBS ON 1 ENG.) NOT SURE WHAT CAUSED THE PROB, BUT DUE TO ALL FIRE INDICATIONS GOING OUT AFTER RETARDING THROTTLE TO IDLE, WOULD SUSPECT BLEED AIR LEAK. (WE TESTED FIRE DETECTION SYS AFTER LIGHTS WENT OUT AND GOT A GOOD CHK.) UPON TALKING WITH LGA ACR MAINT AT LGA, THEY SUSPECTED A BLEED AIR LEAK AS WELL, THOUGH WE NEVER FOUND OUT WITH MAINT AS TO FINAL DETERMINATION.

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.

A DC9-30 on initial climb declared an emergency and diverted due to a left engine fire warning caused by an engine pneumatic leak.