B727 freighter on downwind #1 engine fire warning. Captain and so completed the engine fire checklis...

Attributes
ACN	347530
Time
Date	199609
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : gtf
State Reference	MT
Altitude	msl bound lower : 5000 msl bound upper : 5000
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Controlling Facilities	tower : gtf
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	other other
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : instrument pilot : flight engineer
Experience	flight time last 90 days : 100 flight time total : 10800 flight time type : 4000
ASRS Report	347530
Person 2
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : instrument pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 50 flight time total : 4000 flight time type : 25
ASRS Report	347886
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : overcame equipment problem flight crew : declared emergency
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

We were on a visual approach into gtf about 2 mi east of runway 3 when we had a fire warning on engine #1. The aircraft was configured at flaps 5 degrees with the first officer flying. I told the first officer to continue flying the airplane and to continue with the approach to gtf. The so and I worked the engine fire checklist. At the completion of the checklist, #1 engine was shut down and the fire warning extinguished. The fire warning system was then tested and we had a good test of the system. An emergency was declared during this time with the request for emergency equipment. At this time we were turning onto final for runway 3 and did the before landing checklist. First officer continued to fly and landed the aircraft. After landing we cleared the runway to wait for a visual inspection of engine #1. Before we could stop we had another fire warning on the same engine (#1). At that time I decided to shut down all remaining engines and evacuate/evacuation the aircraft. Afterwards it was discovered that the fire warning was caused by a mechanical failure of the fire warning system. There were no fires. Supplemental information from acn 347886: throughout my so training (ground school, simulator, and IOE), and through my first week out of training, I had not seen this fire warning test system. This particular system was a 3-WAY test switch. Unlike those I had seen in the past (fire wall, off, fire wall and wheel well), this system had a separate test for system a and also for system B (system a, off, system B and ww). In addition, the ground fault light test was also different. All other aircraft I had seen had either no test switch for the ground fault lights, or had the a-ab-B 3-WAY switch. This particular aircraft had a spring loaded toggle switch, a-off- B. On preflight I tested the fire switch both directions with a good test. However, on the engine shutdown checklist when I tested the system I only moved the switch down (to test what I thought was the fire wall and wheel well). I also looked at my aft panel for a ground fault light and had none -- so it appeared the fire test was satisfactory.

Original NASA ASRS Text

Title: B727 FREIGHTER ON DOWNWIND #1 ENG FIRE WARNING. CAPT AND SO COMPLETED THE ENG FIRE CHKLIST AND SHUT THE ENG DOWN, FIRE WARNING OUT. EMER DECLARED AND AFTER CLRING RWY GOT ANOTHER FIRE WARNING SAME ENG. SHUT DOWN ALL ENGS AND EVACED THE ACFT. MAINT FOUND MECHANICAL FAILURE OF THE FIRE WARNING SYS.

Narrative: WE WERE ON A VISUAL APCH INTO GTF ABOUT 2 MI E OF RWY 3 WHEN WE HAD A FIRE WARNING ON ENG #1. THE ACFT WAS CONFIGURED AT FLAPS 5 DEGS WITH THE FO FLYING. I TOLD THE FO TO CONTINUE FLYING THE AIRPLANE AND TO CONTINUE WITH THE APCH TO GTF. THE SO AND I WORKED THE ENG FIRE CHKLIST. AT THE COMPLETION OF THE CHKLIST, #1 ENG WAS SHUT DOWN AND THE FIRE WARNING EXTINGUISHED. THE FIRE WARNING SYS WAS THEN TESTED AND WE HAD A GOOD TEST OF THE SYS. AN EMER WAS DECLARED DURING THIS TIME WITH THE REQUEST FOR EMER EQUIP. AT THIS TIME WE WERE TURNING ONTO FINAL FOR RWY 3 AND DID THE BEFORE LNDG CHKLIST. FO CONTINUED TO FLY AND LANDED THE ACFT. AFTER LNDG WE CLRED THE RWY TO WAIT FOR A VISUAL INSPECTION OF ENG #1. BEFORE WE COULD STOP WE HAD ANOTHER FIRE WARNING ON THE SAME ENG (#1). AT THAT TIME I DECIDED TO SHUT DOWN ALL REMAINING ENGS AND EVAC THE ACFT. AFTERWARDS IT WAS DISCOVERED THAT THE FIRE WARNING WAS CAUSED BY A MECHANICAL FAILURE OF THE FIRE WARNING SYS. THERE WERE NO FIRES. SUPPLEMENTAL INFO FROM ACN 347886: THROUGHOUT MY SO TRAINING (GND SCHOOL, SIMULATOR, AND IOE), AND THROUGH MY FIRST WK OUT OF TRAINING, I HAD NOT SEEN THIS FIRE WARNING TEST SYS. THIS PARTICULAR SYS WAS A 3-WAY TEST SWITCH. UNLIKE THOSE I HAD SEEN IN THE PAST (FIRE WALL, OFF, FIRE WALL AND WHEEL WELL), THIS SYS HAD A SEPARATE TEST FOR SYS A AND ALSO FOR SYS B (SYS A, OFF, SYS B AND WW). IN ADDITION, THE GND FAULT LIGHT TEST WAS ALSO DIFFERENT. ALL OTHER ACFT I HAD SEEN HAD EITHER NO TEST SWITCH FOR THE GND FAULT LIGHTS, OR HAD THE A-AB-B 3-WAY SWITCH. THIS PARTICULAR ACFT HAD A SPRING LOADED TOGGLE SWITCH, A-OFF- B. ON PREFLT I TESTED THE FIRE SWITCH BOTH DIRECTIONS WITH A GOOD TEST. HOWEVER, ON THE ENG SHUTDOWN CHKLIST WHEN I TESTED THE SYS I ONLY MOVED THE SWITCH DOWN (TO TEST WHAT I THOUGHT WAS THE FIRE WALL AND WHEEL WELL). I ALSO LOOKED AT MY AFT PANEL FOR A GND FAULT LIGHT AND HAD NONE -- SO IT APPEARED THE FIRE TEST WAS SATISFACTORY.

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.