Flight Crew Air Transport Pilot (ATP)
Confusion; Troubleshooting; Training / Qualification
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor; Ground Event / Encounter Other / Unknown
Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Maintenance Action
Procedure; Manuals; Human Factors; Aircraft
On Taxi out; received 'Fire Det 2 Fault' Level 1 Alert. Referenced QRH and it stated that this required a 'NO Take-Off' status. After stopping the aircraft to further investigate the situation; I performed another Fire Detection System Test and then following this test we received an 'Eng #2 Fire' Level 3 Alert. We then ran the QRH procedures for Engine Fire/Severe Damage; shut down the engine; discharged the first Fire Bottle. After 30 Seconds we still had the Engine Fire alert and so we discharged the second Fire Bottle. At this time we notified ZZZ Fire Rescue of our possible engine fire. Prior to Fire Rescue's arrival; the 'Eng 2 Fire' Alert had extinguished. Fire Rescue inspected Engine #2 both visually and with Firefighter Thermal Imaging Camera (FLIR) and notified us that it appeared that there wasn't any fire present and that all was safe to taxi back to the Ramp area. Fire Rescue escorted us back to Ramp with no further action on their part. After parking; we debriefed our Maintenance [personnel] and released the aircraft to Company ZZZ Station Maintenance.After discussing the event with our Maintenance; it was determined that the initial fault ('Fire Det 2 Fault') was caused by a Fire Detection Controller System failure; (Intermittent failure). The outcome of this Alert is a total failure of Engine #2 Fire Detection System; so takeoff is not authorized. The Human Factor Error was on my part; when I ran another Fire Detection Test; this I believe caused the 'Engine 2 Fire' Alert due to system design. After the Alert was displayed and failed to extinguish; we had no options but to respond to the Fire Alert; i.e. shut down engine and discharge the Fire Bottles. At this point; without verification from an outside source; we felt our actions were appropriate along with notifying the Fire Rescue. There is no prevention to a system failure; but as far as the possible human error; maybe just sit on my hands and take in the situation for a few minutes before doing any system tests; as they can produce a possible wrong indication.
Reporter stated when they received the initial fault of 'Fire Det 2 Fault'; Level 1 alert; they checked their QRH which only had a reference asking if the Fire Detection System was not available. He just did not know if the Fire Detection System was 'not' available.  So he performed another Fire Detection System Test and that Test set off the 'Eng #2 Fire' Level 3 alert requiring him to shut down #2 Engine and discharge the Engine Fire Bottles. He would like to see the QRH revised to alert flight crews 'not' to perform another Fire Detection System Test if a similar 'Fire Det 2 Fault' Level 1 alert appears.
On taxi out; received a Level-1 ('Fire Det 2 Fail'). After stopping aircraft and checking the QRH for the Level-1 Alert; a Fire Test was accomplished and then we received a Level 3 'Eng 2 Fire' Alert. We suspected an indicator issue; but still had to run QRH procedures; for Engine Fire Severe Damage Checklist.  Fired first [Fire] Bottle and Alert remained 'ON' after 30-seconds. Fired second bottle. After about two minutes; alert went out.  Both 'Fire Det 2 Fail' and 'Eng 2 Fire' indications remained off and 'Agent Lo' Alert was on. Alerted Ground Control to send out fire trucks while we were still on the taxiway as a precaution. They inspected the Number-2 Engine area and found no evidence of a fire. We taxied back to the gate and had the Fire Department follow us. We suspect that the Fire Detection System failure caused false indications which led to this event.
A Captain and First Officer report that during taxi out in an MD-11 aircraft; a 'Fire Det 2 Fault' Level-1 Alert appeared. QRH stated 'No Take-Off' status. Another Fire Detection System Test was performed; followed by 'Eng #2 Fire' Level-3 Alert. Both Fire Bottles were discharged. Fire Rescue checked engine and said no fire present. Fire Detection Controller had failed.