Narrative:

When I arrived at the aircraft there was a maintenance placard in the aircraft log book stating, 'pitot 3 fault light inoperative per MEL 30-9, authority/authorized 7-108c-C.' the MEL says, 'all [pitot fault lights] may be inoperative provided maintenance verifies that associated mfd fault messages and related alerts are operative per mpm 30-9.' I called the FK100 specialist at our technical center to ask what the mpm 30-9 procedure consisted of and how they knew the problem was in the fault light and not an inoperative pitot heater. I was told that mpm 30-9 was a very complicated, 2 page diagnostic procedure that checked the entire system. That sounded reasonable to me, so I flew the aircraft 3 legs. 4 days later, I was notified by a chief pilot that our maintenance had decided that notwithstanding their mpm 30-9 procedure, they had come to the wrong conclusion, and the #3 pitot heater had been inoperative, not the fault light. The placard was therefore invalid and maintenance had reported their error to the appropriate FAA airworthiness office. I am writing this because I am now guilty, retroactively, of flying an aircraft that was not airworthy. I do not know what else I could have done to check the validity of the maintenance placard. At some point you just have to have faith in the integrity of the system.

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Original NASA ASRS Text

Title: CAPT OF A FK100 LEARNS THAT HE HAD OPERATED AN UNAIRWORTHY ACFT DUE TO A REDETERMINATION BY MAINT OF THE REAL ACFT DISCREPANCY. SUBSEQUENTLY FOUND COULD NOT BE MEL'ED!

Narrative: WHEN I ARRIVED AT THE ACFT THERE WAS A MAINT PLACARD IN THE ACFT LOG BOOK STATING, 'PITOT 3 FAULT LIGHT INOP PER MEL 30-9, AUTH 7-108C-C.' THE MEL SAYS, 'ALL [PITOT FAULT LIGHTS] MAY BE INOP PROVIDED MAINT VERIFIES THAT ASSOCIATED MFD FAULT MESSAGES AND RELATED ALERTS ARE OPERATIVE PER MPM 30-9.' I CALLED THE FK100 SPECIALIST AT OUR TECHNICAL CTR TO ASK WHAT THE MPM 30-9 PROC CONSISTED OF AND HOW THEY KNEW THE PROB WAS IN THE FAULT LIGHT AND NOT AN INOP PITOT HEATER. I WAS TOLD THAT MPM 30-9 WAS A VERY COMPLICATED, 2 PAGE DIAGNOSTIC PROC THAT CHKED THE ENTIRE SYS. THAT SOUNDED REASONABLE TO ME, SO I FLEW THE ACFT 3 LEGS. 4 DAYS LATER, I WAS NOTIFIED BY A CHIEF PLT THAT OUR MAINT HAD DECIDED THAT NOTWITHSTANDING THEIR MPM 30-9 PROC, THEY HAD COME TO THE WRONG CONCLUSION, AND THE #3 PITOT HEATER HAD BEEN INOP, NOT THE FAULT LIGHT. THE PLACARD WAS THEREFORE INVALID AND MAINT HAD RPTED THEIR ERROR TO THE APPROPRIATE FAA AIRWORTHINESS OFFICE. I AM WRITING THIS BECAUSE I AM NOW GUILTY, RETROACTIVELY, OF FLYING AN ACFT THAT WAS NOT AIRWORTHY. I DO NOT KNOW WHAT ELSE I COULD HAVE DONE TO CHK THE VALIDITY OF THE MAINT PLACARD. AT SOME POINT YOU JUST HAVE TO HAVE FAITH IN THE INTEGRITY OF THE SYS.

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.