B717 (Formerly MD-95)
Distraction; Human-Machine Interface; Troubleshooting; Confusion
Aircraft Equipment Problem Critical
Flight Crew Diverted; Flight Crew Landed in Emergency Condition; General Declared Emergency
Procedure; Aircraft
Aircraft...had been in maintenance and had come out of a maintenance service check. There were no flights after the service check; ours was the first. Because the B717s have been experiencing a substantial deterioration in the quality of maintenance they have been receiving; I reviewed the aircraft logbook prior to the service check to see if any significant issues had been reported (of note: all the discrepancies that I reviewed had been signed off or appropriately MEL'd at the time the discrepancy was noted and thereafter cleared prior to or during the service check). The logbook history made me aware of a significant history regarding not just repeated false fire indications concerning the left engine; but other repetitious issues with the left engine fire protection system. I was also aware; through my review of the logbook; of other significant and repetitive issues concerning the loss of flight information on Display Units 1 and 2. The maintenance history of the aircraft; specifically the repeated malfunctions pertaining to such important systems; and the Maintenance Department's inability to resolve the issues (again; despite the discrepancies being repeatedly signed off as repaired) concerned me so much that I requested that the First Officer also review the logbook beginning well prior to the service check. I was so concerned that I also mentioned that the aircraft had been having significant issues to the Lead Flight Attendant as part of her preflight briefing. While in cruise flight; we experienced a rapid and intermittent Engine Fire alert for the left engine. The rapid and intermittent nature of the Engine Fire alert made it impossible to proceed with the Engine Fire or Severe Damage Checklist. The Engine Fire Checklist only allowed for a 'yes' or 'no' decision as to whether the Fire alert was still displayed - it did not allow for a 'maybe' where the Engine Fire alert would be displayed; then cease; the fire protection system to then test properly (indicting that there was no longer a fire and the fire detection system was functioning normally) and then an Engine Fire alert to resume; cease; test normally; and have this cycle repeating indefinitely. As an aside: the alert itself was a substantial and continuing cockpit distraction as it was intermittent and therefore could not be effectively silenced....The maintenance history of the aircraft as described above; in my opinion as Captain under my emergency authority; made it inappropriate to shut down the left engine as described in the Emergency Checklist. Such action would have placed the aircraft; crew and passengers in a position where we would have lost several systems (such as all fire suppression should I have discharged the fire bottles) associated with running that checklist; but much more importantly; also put us in any number of situations where a single point of failure (such as of the right engine) could have possibly destroyed the aircraft and resulted in injuries to; and the fatalities of; any number of the passengers and crew.... We were faced with a choice for which there were no good answers or guidance as the Emergency Checklist allowed for only two choices; both of which could have easily been either right or wrong: (1) ignoring the albeit muddy direction of the Emergency Checklist and allowing an engine to continue running which was; according to the fire protection system on the aircraft; on fire; or (2) proceeding with the Emergency Checklist and shutting down; for no other reason than an fire indication which had been repeatedly documented as false; a perfectly good engine which was operating normally....When the Engine Fire Alert went off; [a divert] airport was within 40 miles and I could see it; including the individual runways; visually. Because of my familiarity with the [this] airport; I decided that there was no risk associated with a diversion to that airport. I declared an emergency and requested crash; fire andrescue equipment. After landing there was no further incident. About the only thing I would have done differently is to have refused the aircraft [at departure airport]. That would have raised any number of additional issues - not the least of which would be management being very displeased with pilots who refuse aircraft that have a clean bill of health.
B717-200 flight crew diverted with apparent false left engine Fire Warning. Aircraft had a history of multiple false fire warnings; but had just been released from a maintenance service check with all discrepancies signed off.