Narrative:

I wrote this report this morning because I just realized today that although we followed company procedures; there is a flaw in this application of the MEL. If I had known about it sooner I would have reported it immediately. This MEL needs to be revised immediately. A report was completed within a few hours of the trip completion. We started in pdx and were to fly the plane cross country. The airplane had three mels; one of which was a performance computer (thus no MEL for reference). During the preflight of the aircraft; we found the left wing body overheat would not test properly. A light test and push test of the light proved the bulbs where good. I contacted dispatch to discuss the issue with him. The dispatcher looked up the MEL for the light. We discussed possible scenarios. We both felt better having contract maintenance look at it. Contract maintenance showed up and we discussed the problem. The mechanics went to look for 'faults' on the computers in the east and east bay. They told me no faults were shown. I called dispatch back and had maintenance control help us defer the left bleed per the MEL. I write this report because of the conversation with maintenance control that followed. Maintenance told me (I'm paraphrasing because I can not recall the exact words); 'captain; you cost the company a lot of money calling contract maintenance out. We won't make any money on this flight because of this.' I responded that safety is our number one priority. He said; 'well do you feel better now that contract maintenance looked at it' I said yes; because they looked for faults stored in the computer. I also explained; 'how a pilot is very keenly aware of operational costs and it is secondary to safety.' the statements regarding the cost issue were out of line and inappropriate. Safety first. Always! Additional concerns: I was optimistic that the issue could have been fixed easily. Flying at 25;000 ft from pdx east burns a tremendous amount of additional fuel; approximately 5500 pounds of extra fuel. Limiting us to FL250; passenger comfort with single pack operation; both legs booked to 137 passengers. Enroute; terrain and thunderstorms forecast. Having said that; this morning I realized that the MEL 26-12 does not address flight over mountainous terrain. The scenario could have been like this: the left engine bleed and left pack were unusable due to the left wing body overheat was deferred. Our flight could have had the right engine fail or right pack fail. As we cross the rocky mountains there is an area where the MEA is FL210. In the event of pressurization loss we would be unable to descend below 10;000 ft. If I had realized this possible hazard at the time; or if the MEL addressed this; I would have either been rerouted away from high terrain or been unable to use that aircraft for the trip. I feel there should be a restriction in place in the MEL for single pack operation over mountainous terrain.

Google
 

Original NASA ASRS Text

Title: A Captain realized after a cross-country flight with a wing body overheat warning MEL; that single pack flight at FL250 across the Rockies may not be allowable. The reason being the aircraft may not be able to descend to 10;000 FT in the event the other pack or engine fails because of higher MEA's.

Narrative: I wrote this report this morning because I just realized today that although we followed Company procedures; there is a flaw in this application of the MEL. If I had known about it sooner I would have reported it immediately. This MEL needs to be revised immediately. A report was completed within a few hours of the trip completion. We started in PDX and were to fly the plane cross country. The airplane had three MELs; one of which was a performance computer (thus no MEL for reference). During the preflight of the aircraft; we found the Left Wing Body Overheat would not test properly. A light test and push test of the light proved the bulbs where good. I contacted Dispatch to discuss the issue with him. The Dispatcher looked up the MEL for the light. We discussed possible scenarios. We both felt better having Contract Maintenance look at it. Contract Maintenance showed up and we discussed the problem. The Mechanics went to look for 'faults' on the computers in the E and E bay. They told me no faults were shown. I called Dispatch back and had Maintenance Control help us defer the left bleed per the MEL. I write this report because of the conversation with Maintenance Control that followed. Maintenance told me (I'm paraphrasing because I can not recall the exact words); 'Captain; you cost the company a lot of money calling Contract Maintenance out. We won't make any money on this flight because of this.' I responded that Safety is our number one priority. He said; 'Well do you feel better now that Contract Maintenance looked at it' I said yes; because they looked for faults stored in the computer. I also explained; 'How a Pilot is very keenly aware of operational costs and it is secondary to safety.' The statements regarding the cost issue were out of line and inappropriate. Safety first. Always! Additional concerns: I was optimistic that the issue could have been fixed easily. Flying at 25;000 FT from PDX east burns a tremendous amount of additional fuel; approximately 5500 LBS of extra fuel. Limiting us to FL250; passenger comfort with single pack operation; both legs booked to 137 Passengers. Enroute; terrain and thunderstorms forecast. Having said that; this morning I realized that the MEL 26-12 does not address flight over mountainous terrain. The scenario could have been like this: The left engine bleed and left pack were unusable due to the Left Wing Body Overheat was deferred. Our flight could have had the right engine fail or right pack fail. As we cross the Rocky Mountains there is an area where the MEA is FL210. In the event of pressurization loss we would be unable to descend below 10;000 FT. If I had realized this possible hazard at the time; or if the MEL addressed this; I would have either been rerouted away from high terrain or been unable to use that aircraft for the trip. I feel there should be a restriction in place in the MEL for single pack operation over mountainous terrain.

Data retrieved from NASA's ASRS site as of April 2012 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.