Narrative:

It was found, during the taxi checklist, that the #2 navigation radio was inoperative (HSI). We then consulted the MEL for the aircraft and both myself and my copilot agreed that, based on the wording of the MEL, the aircraft was airworthy to fly part 135, IFR. The #2 navigation radio was written up in the dr's by the copilot. During the course of our shift, other pilots within the company were queried as to the interpretation of the MEL. All thought the wording of the MEL was ambiguous. The maintenance department decided to repair the radio before any further part 135 IFR flts could occur. I feel that the wording of the MEL, which I've included, contributed greatly to this misunderstanding. The MEL should be more specific. It should not be necessary for a flight crew to discuss semantics at the end of a runway, in the middle of the night, in IMC. A panel of ATP's, typed in the aircraft, in the comfort of a pilot's lounge could not agree on an interpretation. We all believed, however, that if the MEL specifically stated '2 VOR receivers are required for IFR part 135' no problem like this would occur. MEL, revision #10, page 34-1, system and sequence numbers: -4A VOR receivers, remarks or exceptions: one may be inoperative for: part 135 -- one required for VFR or VFR over-the- top. None required for operations navigated by pilotage. Part 91 -- one required for IFR. None required for VFR.

Related reports:

Google
 

Original NASA ASRS Text

Title: AN LTT ACR FGT CREW FLEW AT NIGHT WITH AN IFR FLT PLAN WITH ONLY 1 NAV RECEIVER.

Narrative: IT WAS FOUND, DURING THE TAXI CHKLIST, THAT THE #2 NAV RADIO WAS INOP (HSI). WE THEN CONSULTED THE MEL FOR THE ACFT AND BOTH MYSELF AND MY COPLT AGREED THAT, BASED ON THE WORDING OF THE MEL, THE ACFT WAS AIRWORTHY TO FLY PART 135, IFR. THE #2 NAV RADIO WAS WRITTEN UP IN THE DR'S BY THE COPLT. DURING THE COURSE OF OUR SHIFT, OTHER PLTS WITHIN THE COMPANY WERE QUERIED AS TO THE INTERP OF THE MEL. ALL THOUGHT THE WORDING OF THE MEL WAS AMBIGUOUS. THE MAINT DEPT DECIDED TO REPAIR THE RADIO BEFORE ANY FURTHER PART 135 IFR FLTS COULD OCCUR. I FEEL THAT THE WORDING OF THE MEL, WHICH I'VE INCLUDED, CONTRIBUTED GREATLY TO THIS MISUNDERSTANDING. THE MEL SHOULD BE MORE SPECIFIC. IT SHOULD NOT BE NECESSARY FOR A FLC TO DISCUSS SEMANTICS AT THE END OF A RWY, IN THE MIDDLE OF THE NIGHT, IN IMC. A PANEL OF ATP'S, TYPED IN THE ACFT, IN THE COMFORT OF A PLT'S LOUNGE COULD NOT AGREE ON AN INTERP. WE ALL BELIEVED, HOWEVER, THAT IF THE MEL SPECIFICALLY STATED '2 VOR RECEIVERS ARE REQUIRED FOR IFR PART 135' NO PROB LIKE THIS WOULD OCCUR. MEL, REVISION #10, PAGE 34-1, SYSTEM AND SEQUENCE NUMBERS: -4A VOR RECEIVERS, REMARKS OR EXCEPTIONS: ONE MAY BE INOP FOR: PART 135 -- ONE REQUIRED FOR VFR OR VFR OVER-THE- TOP. NONE REQUIRED FOR OPS NAVIGATED BY PILOTAGE. PART 91 -- ONE REQUIRED FOR IFR. NONE REQUIRED FOR VFR.

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.