Narrative:

Later discussion with the fire chief revealed that he was seeing smoke coming out of #1 engine oil breather when he made both requests for aircraft evacuate/evacuation. #1 and #2 engines were both normal. #3 engine was shut down. FL330 in cruise, first officer flying,, captain making passenger announcement. #3 fir bel and light activated. Captain directed first officer to fly the aircraft. Captain and second officer accomplished procedure. Light still on after both bottles fired. Captain requested lower altitude and distance to nearest suitable airport. ZLC advised bil at 140 DME, gtf at 15 DME. Captain selected gtf and requested expedited service to it. Fire light went out. Captain took over controls and started expedite descent per ATC approval. Second officer asked to advise F/a crew. Second officer asked to verify landing weight within limits. Second officer advised captain weight within limits. Light and bell came back on. Captain and second officer reviewed checklist to verify all items. Handed off to gtf approach. Captain declared emergency and requested fire quip. Assigned runway 21 and cleared to land. All traffic vectored away. Captain made brief passenger announcement advising of precautionary landing at gtf because of engine overheat indication. Made normal landing. Turned off runway and stopped on parallel taxiway. Captain made brief passenger announcement advising that ground equipment was visually checking aircraft and to please remain seated. Note: cockpit crew and fire chief were communicating via ground control. Fire chief advised, 'no fire, no smoke' (fire light off). Tower asked if we wished to taxi to gate with equipment following. We advised yes and prepared to taxi. Second officer started APU. Suddenly fire chief advised of 'smoke.' we stopped and set brakes. Chief requested we evacuate/evacuation aircraft. Captain requested that fire chief verify 'smoke not coming from top of right wing--suspected APU fogging.' chief advised smoke coming form engine and made second request to evacuate/evacuation aircraft from 'forward exits.' at that moment, #3 fire bell and light went off for third time. Second officer advised, 'oil temperature is very high.' captain ordered F/a's to evacuate/evacuation aircraft out of main and forward galley doors only. Evacuate/evacuation started immediately and proceeded normally. Checklist finished. Cockpit assumed evacuate/evacuation stations. Captain ascertained no smoke in cabin and none seen through any windows. Conclusion: some 135 passenger and crew were evacked west/O incident or injury. Callback conversation with reporter revealed the following: reporter called back to inform ASRS that the warning had been a false one and that the air carrier, upon a post flight inspection, determined that the casing containing the fire warning sensors (a gas that works on expansion/contraction from heat) had been partially crushed. This was of particular concern to maintenance and flight crew as the stainless steel tubing had a long impacted area in the front of about 6' and would have been obvious to any mechanic who was qualified on the aircraft prior to closing the engine cowling. The PIC (reporter) felt, in a personal way, that this could have happened on one of the minor station stops during an engine oil check. The communication mix-up with the fire chief occurred because of the fact that no engine was referred to by # and the reporter doesn't even know if the fire chief was aware of the numbering system on the engines. The timing was interesting. Just as the fire chief said that he wanted the aircraft evacked, the fire bell went off again. Captain said to first officer, just as that occurred, 'I wonder if this is a real fire; I doubt it.' PIC felt he had no choice but to comply.

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Original NASA ASRS Text

Title: ACR LGT MAKES AN EMER LNDG AFTER AN INFLT ENGINE FIRE WARNING THAT KEEPS RECURRING AFTER FIRE BOTTLES ARE DISCHARGED. PASSENGERS EVACUATED AFTER GND ADVISORY FROM FIRE CHIEF THAT SMOKE IS COMING FROM THE ENGINE.

Narrative: LATER DISCUSSION WITH THE FIRE CHIEF REVEALED THAT HE WAS SEEING SMOKE COMING OUT OF #1 ENG OIL BREATHER WHEN HE MADE BOTH REQUESTS FOR ACFT EVAC. #1 AND #2 ENGS WERE BOTH NORMAL. #3 ENG WAS SHUT DOWN. FL330 IN CRUISE, F/O FLYING,, CAPT MAKING PAX ANNOUNCEMENT. #3 FIR BEL AND LIGHT ACTIVATED. CAPT DIRECTED F/O TO FLY THE ACFT. CAPT AND S/O ACCOMPLISHED PROC. LIGHT STILL ON AFTER BOTH BOTTLES FIRED. CAPT REQUESTED LOWER ALT AND DISTANCE TO NEAREST SUITABLE ARPT. ZLC ADVISED BIL AT 140 DME, GTF AT 15 DME. CAPT SELECTED GTF AND REQUESTED EXPEDITED SVC TO IT. FIRE LIGHT WENT OUT. CAPT TOOK OVER CTLS AND STARTED EXPEDITE DSNT PER ATC APPROVAL. S/O ASKED TO ADVISE F/A CREW. S/O ASKED TO VERIFY LNDG WT WITHIN LIMITS. S/O ADVISED CAPT WT WITHIN LIMITS. LIGHT AND BELL CAME BACK ON. CAPT AND S/O REVIEWED CHKLIST TO VERIFY ALL ITEMS. HANDED OFF TO GTF APCH. CAPT DECLARED EMER AND REQUESTED FIRE QUIP. ASSIGNED RWY 21 AND CLRED TO LAND. ALL TFC VECTORED AWAY. CAPT MADE BRIEF PAX ANNOUNCEMENT ADVISING OF PRECAUTIONARY LNDG AT GTF BECAUSE OF ENG OVERHEAT INDICATION. MADE NORMAL LNDG. TURNED OFF RWY AND STOPPED ON PARALLEL TXWY. CAPT MADE BRIEF PAX ANNOUNCEMENT ADVISING THAT GND EQUIP WAS VISUALLY CHKING ACFT AND TO PLEASE REMAIN SEATED. NOTE: COCKPIT CREW AND FIRE CHIEF WERE COMMUNICATING VIA GND CTL. FIRE CHIEF ADVISED, 'NO FIRE, NO SMOKE' (FIRE LIGHT OFF). TWR ASKED IF WE WISHED TO TAXI TO GATE WITH EQUIP FOLLOWING. WE ADVISED YES AND PREPARED TO TAXI. S/O STARTED APU. SUDDENLY FIRE CHIEF ADVISED OF 'SMOKE.' WE STOPPED AND SET BRAKES. CHIEF REQUESTED WE EVAC ACFT. CAPT REQUESTED THAT FIRE CHIEF VERIFY 'SMOKE NOT COMING FROM TOP OF RIGHT WING--SUSPECTED APU FOGGING.' CHIEF ADVISED SMOKE COMING FORM ENG AND MADE SECOND REQUEST TO EVAC ACFT FROM 'FORWARD EXITS.' AT THAT MOMENT, #3 FIRE BELL AND LIGHT WENT OFF FOR THIRD TIME. S/O ADVISED, 'OIL TEMP IS VERY HIGH.' CAPT ORDERED F/A'S TO EVAC ACFT OUT OF MAIN AND FORWARD GALLEY DOORS ONLY. EVAC STARTED IMMEDIATELY AND PROCEEDED NORMALLY. CHKLIST FINISHED. COCKPIT ASSUMED EVAC STATIONS. CAPT ASCERTAINED NO SMOKE IN CABIN AND NONE SEEN THROUGH ANY WINDOWS. CONCLUSION: SOME 135 PAX AND CREW WERE EVACKED W/O INCIDENT OR INJURY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR CALLED BACK TO INFORM ASRS THAT THE WARNING HAD BEEN A FALSE ONE AND THAT THE ACR, UPON A POST FLT INSPECTION, DETERMINED THAT THE CASING CONTAINING THE FIRE WARNING SENSORS (A GAS THAT WORKS ON EXPANSION/CONTRACTION FROM HEAT) HAD BEEN PARTIALLY CRUSHED. THIS WAS OF PARTICULAR CONCERN TO MAINT AND FLT CREW AS THE STAINLESS STEEL TUBING HAD A LONG IMPACTED AREA IN THE FRONT OF ABOUT 6' AND WOULD HAVE BEEN OBVIOUS TO ANY MECH WHO WAS QUALIFIED ON THE ACFT PRIOR TO CLOSING THE ENG COWLING. THE PIC (RPTR) FELT, IN A PERSONAL WAY, THAT THIS COULD HAVE HAPPENED ON ONE OF THE MINOR STATION STOPS DURING AN ENG OIL CHK. THE COM MIX-UP WITH THE FIRE CHIEF OCCURRED BECAUSE OF THE FACT THAT NO ENG WAS REFERRED TO BY # AND THE RPTR DOESN'T EVEN KNOW IF THE FIRE CHIEF WAS AWARE OF THE NUMBERING SYS ON THE ENGS. THE TIMING WAS INTERESTING. JUST AS THE FIRE CHIEF SAID THAT HE WANTED THE ACFT EVACKED, THE FIRE BELL WENT OFF AGAIN. CAPT SAID TO F/O, JUST AS THAT OCCURRED, 'I WONDER IF THIS IS A REAL FIRE; I DOUBT IT.' PIC FELT HE HAD NO CHOICE BUT TO COMPLY.

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.