Narrative:

Descending through 8000 ft IMC with moderate rain #1 (left) engine fire warning came on. We shut down the engine and complied with the memory items and the emergency/checklists as time permitted. After firing shot #1 we still had an indication of fire. Shot #2 was fired; after the specified timing (45 seconds) we still had an indication that the #1 engine was on fire. We asked both flight attendants to look closely at the engine and advise if they saw any fire or smoke. Their reply was that everything looked normal -- no fire/no smoke. As all of this was happening pia approach was notified of the emergency and called WX at our 12 O'clock and 5 mi; the WX radar indicated just light rain. We continued to the airport on a vector to int. ILS 13 (65 OTS) the runway was sighted near MOA about 2 mi out. After clearing the runway crash fire rescue equipment inspected us. We both noticed that neither red dolls-eye (magnetic indicator 1/8 inch diameter shows red when bottle discharges) was showing red. Post flight examination also showed the thermal/elec discharge (green disc on side of nacelle) was still in place. We pulled the crash fire rescue equipment circuit breaker to preserve the evidence that we had carried out the shut-down and fire drill. Later the same day maintenance advised us that they had found a direct short in the fire-loop; oil soaked cannon plugs to the fire bottles; and broken wires in the cannon plug. The short heated the loop to indicate a fire. The broken wires prevented the fire bottles discharge. We've had other false fire warning -- a 2 loop system might help. The acceptance check of the fire detection/protection checks the integrity of the loop and the bells and lights in the cockpit. There is no way to know if there is power to the firing pins at the bottles without discharging the bottle.

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Original NASA ASRS Text

Title: FOREIGN MADE MLG EXPERIENCES A FIRE WARNING. CREW DECLARES AN INFLT EMER, LANDS SOON AS POSSIBLE.

Narrative: DSNDING THROUGH 8000 FT IMC WITH MODERATE RAIN #1 (L) ENG FIRE WARNING CAME ON. WE SHUT DOWN THE ENG AND COMPLIED WITH THE MEMORY ITEMS AND THE EMER/CHKLISTS AS TIME PERMITTED. AFTER FIRING SHOT #1 WE STILL HAD AN INDICATION OF FIRE. SHOT #2 WAS FIRED; AFTER THE SPECIFIED TIMING (45 SECONDS) WE STILL HAD AN INDICATION THAT THE #1 ENG WAS ON FIRE. WE ASKED BOTH FLT ATTENDANTS TO LOOK CLOSELY AT THE ENG AND ADVISE IF THEY SAW ANY FIRE OR SMOKE. THEIR REPLY WAS THAT EVERYTHING LOOKED NORMAL -- NO FIRE/NO SMOKE. AS ALL OF THIS WAS HAPPENING PIA APCH WAS NOTIFIED OF THE EMER AND CALLED WX AT OUR 12 O'CLOCK AND 5 MI; THE WX RADAR INDICATED JUST LIGHT RAIN. WE CONTINUED TO THE ARPT ON A VECTOR TO INT. ILS 13 (65 OTS) THE RWY WAS SIGHTED NEAR MOA ABOUT 2 MI OUT. AFTER CLRING THE RWY CFR INSPECTED US. WE BOTH NOTICED THAT NEITHER RED DOLLS-EYE (MAGNETIC INDICATOR 1/8 INCH DIAMETER SHOWS RED WHEN BOTTLE DISCHARGES) WAS SHOWING RED. POST FLT EXAMINATION ALSO SHOWED THE THERMAL/ELEC DISCHARGE (GREEN DISC ON SIDE OF NACELLE) WAS STILL IN PLACE. WE PULLED THE CFR CIRCUIT BREAKER TO PRESERVE THE EVIDENCE THAT WE HAD CARRIED OUT THE SHUT-DOWN AND FIRE DRILL. LATER THE SAME DAY MAINT ADVISED US THAT THEY HAD FOUND A DIRECT SHORT IN THE FIRE-LOOP; OIL SOAKED CANNON PLUGS TO THE FIRE BOTTLES; AND BROKEN WIRES IN THE CANNON PLUG. THE SHORT HEATED THE LOOP TO INDICATE A FIRE. THE BROKEN WIRES PREVENTED THE FIRE BOTTLES DISCHARGE. WE'VE HAD OTHER FALSE FIRE WARNING -- A 2 LOOP SYS MIGHT HELP. THE ACCEPTANCE CHK OF THE FIRE DETECTION/PROTECTION CHKS THE INTEGRITY OF THE LOOP AND THE BELLS AND LIGHTS IN THE COCKPIT. THERE IS NO WAY TO KNOW IF THERE IS PWR TO THE FIRING PINS AT THE BOTTLES WITHOUT DISCHARGING THE BOTTLE.

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.