A MULTITUDE OF MINOR ELECTRICAL PROBLEMS LEADS FLC TO TREAT CARGO FIRE WARNING AS A FALSE WARNING AFTER A BRIEF ILLUMINATION.

Date: 1992-03 · Aircraft: Large Transport; Low Wing; 2 Turbojet Eng · Phase: approach

Anomalies: aircraft-equipment-problem-critical|deviation-discrepancy-procedural-published-material-policy

Synopsis

A MULTITUDE OF MINOR ELECTRICAL PROBLEMS LEADS FLC TO TREAT CARGO FIRE WARNING AS A FALSE WARNING AFTER A BRIEF ILLUMINATION.

Narrative

ON FINAL APCH INTO ATL AT APPROX 1500 FT A 'CARGO FIRE WARNING' LIGHT CAME ON FOR APPROX 1 SECOND. IT WAS ON JUST LONG ENOUGH TO SEE THE WORDS 'CARGO FIRE' THEN THE LIGHT AND WARNING WENT OUT. THE CAPT ASSUMED CTL OF THE ACFT AND HAD ME REVIEW THE ABNORMAL PROCS. SINCE THE LIGHT HAD GONE OUT SO QUICKLY WE WERE UNABLE TO TELL WHICH LIGHT HAD COME ON; I.E.; 'FORWARD OR AFT.' DUE TO THE CLOSE PROX TO THE ARPT; AND THE FACT THAT WE BELIEVED IT TO BE A FALSE WARNING; WE ELECTED NOT TO DISCHARGE ANY FIRE EXTINGUISHERS; AND CONTINUED APCH AND LNDG. THE FLT ATTENDANTS WERE NOTIFIED AND WERE TOLD TO CALL US AT THE SLIGHTEST SUSPICION OF SMOKE OR FIRE. AFTER LNDG; MAINT WAS NOTIFIED AND THE FIRE WARNING WAS WRITTEN UP IN THE LOGBOOK. NO EVIDENCE OF A CARGO FIRE WAS FOUND. EARLIER THROUGHOUT THE FLT WE HAD OTHER UNRELATED ELECTRICAL ABNORMALITIES THAT HAD TAKEN PLACE. THEY WERE AS FOLLOWS: 1) INITIALLY AFTER ENG START ELECTRICAL PWR WOULD NOT TRANSFER FROM GND PWR (THE APU WAS INOP) TO THE ACFT; WITHOUT RESETTING THE 'GEN CONT.' 2) AFTER ENG START A 'REV ISLN' STATUS MESSAGE APPEARED THAT MAINT WAS FINALLY ABLE TO CLR AFTER 15 MINS AND AFTER SHUTTING THE ENG DOWN AND RESTARTING IT. 3) DURING CLBOUT THE L PACK TEMP DID NOT WORK IN THE AUTO MODE. AFTER USING MANUAL MODE FOR APPROX 20 MINS WE RETURNED THE SYS TO AUTO AND IT WORKED FINE. OUR OVERALL CONFIDENCE LEVEL IN THE ELECTRICS AND WARNING SYS WAS LOWER THAN NORMAL; WHICH IS WHY WE ELECTED TO MONITOR FOR A MORE CREDIBLE 'CARGO FIRE WARNING' PRIOR TO SHOOTING THE BOTTLES.

Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.