A BE1900 crew return land at fwa when their fire warning system gives mixed signals.

Attributes
ACN	450842
Time
Date	199909
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : fwa.airport
State Reference	IN
Altitude	agl bound lower : 0 agl bound upper : 500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : fwa.tower
Operator	common carrier : air carrier
Make Model Name	Beech 1900
Operating Under FAR Part	Part 135
Flight Phase	climbout : initial climbout : takeoff
Route In Use	departure : other published ifr departure
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp pilot : multi engine pilot : instrument
Experience	flight time last 90 days : 250 flight time total : 3500 flight time type : 1600
ASRS Report	450842
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : landed as precaution
Consequence	other
Supplementary
Problem Areas	Company Aircraft Maintenance Human Performance
Primary Problem	Aircraft

Narrative:

After takeoff, the left fire loop light came on, indicating a problem with the fire detection system. The light went out, then the left fire warning light came on. Both lights then went on and off intermittently. All engine indications were normal and there was no visual signs of a fire. We advised the tower of the situation and made a precautionary landing at fwa airport. We made a normal landing and there were no more fire warning indications. A mechanic determined that the fire loop was loose and was shorting out on the engine, causing the false warning.

Original NASA ASRS Text

Title: A BE1900 CREW RETURN LAND AT FWA WHEN THEIR FIRE WARNING SYS GIVES MIXED SIGNALS.

Narrative: AFTER TKOF, THE L FIRE LOOP LIGHT CAME ON, INDICATING A PROB WITH THE FIRE DETECTION SYS. THE LIGHT WENT OUT, THEN THE L FIRE WARNING LIGHT CAME ON. BOTH LIGHTS THEN WENT ON AND OFF INTERMITTENTLY. ALL ENG INDICATIONS WERE NORMAL AND THERE WAS NO VISUAL SIGNS OF A FIRE. WE ADVISED THE TWR OF THE SIT AND MADE A PRECAUTIONARY LNDG AT FWA ARPT. WE MADE A NORMAL LNDG AND THERE WERE NO MORE FIRE WARNING INDICATIONS. A MECH DETERMINED THAT THE FIRE LOOP WAS LOOSE AND WAS SHORTING OUT ON THE ENG, CAUSING THE FALSE WARNING.

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.