<< >> NASA ASRS Report 105691, February 1989

Aircraft minimum equipment list was misinterpreted causing inoperative aircraft system to be illegally deferred.

Attributes
ACN	105691
Time
Date	198902
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : den
State Reference	CO
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Navigation In Use	Other
Flight Phase	ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp pilot : instrument
Experience	flight time last 90 days : 300 flight time total : 9700 flight time type : 600
ASRS Report	105691
Person 2
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : critical non adherence : far
Independent Detector	other other : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Airport
Air Traffic Incident	Pilot Deviation

Narrative:

While conducting the preflight before a night leg, I discovered the emergency panel lights were inoperative. I wrote it up in the log book and notified maintenance. After looking at the MEL, which did not specify emergency panel lights, only cockpit lighting in general, it was decided to defer the item. All the other lights were working and several flashlights were on board, so the safety of the flight was not a question. A few days later it was brought to my attention that because the emergency panel lights were not specifically mentioned in the MEL, then operation of the aircraft with the lights deferred was illegal. The MEL has since been changed to include the emergency panel lights with a day only restriction. It turned out the switch was faulty and was back-ordered at the factory, so the item could not have been repaired immediately anyway.

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Original NASA ASRS Text

Title: ACFT MINIMUM EQUIPMENT LIST WAS MISINTERPRETED CAUSING INOPERATIVE ACFT SYSTEM TO BE ILLEGALLY DEFERRED.

Narrative: WHILE CONDUCTING THE PREFLT BEFORE A NIGHT LEG, I DISCOVERED THE EMER PANEL LIGHTS WERE INOP. I WROTE IT UP IN THE LOG BOOK AND NOTIFIED MAINT. AFTER LOOKING AT THE MEL, WHICH DID NOT SPECIFY EMER PANEL LIGHTS, ONLY COCKPIT LIGHTING IN GENERAL, IT WAS DECIDED TO DEFER THE ITEM. ALL THE OTHER LIGHTS WERE WORKING AND SEVERAL FLASHLIGHTS WERE ON BOARD, SO THE SAFETY OF THE FLT WAS NOT A QUESTION. A FEW DAYS LATER IT WAS BROUGHT TO MY ATTN THAT BECAUSE THE EMER PANEL LIGHTS WERE NOT SPECIFICALLY MENTIONED IN THE MEL, THEN OPERATION OF THE ACFT WITH THE LIGHTS DEFERRED WAS ILLEGAL. THE MEL HAS SINCE BEEN CHANGED TO INCLUDE THE EMER PANEL LIGHTS WITH A DAY ONLY RESTRICTION. IT TURNED OUT THE SWITCH WAS FAULTY AND WAS BACK-ORDERED AT THE FACTORY, SO THE ITEM COULD NOT HAVE BEEN REPAIRED IMMEDIATELY ANYWAY.

Data retrieved from NASA's ASRS site as of August 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.