Narrative:

Carrier maintenance control used MEL 21-18 to keep the aircraft in service to buy more time to make repairs. Arrived at aircraft X to operate flight in may 2009. Logbook showed MEL 21-18 auto and manual pressurization inop. When I referenced the logbook page to find the original discrepancy it showed 'service door squeals' I have run into this same situation before and I do not believe this to be a proper use of MEL 21-18 as both the manual and auto pressurization systems were functioning properly. There is no relief in the MEL for a door seal. In my opinion; to deactivate an operable system and then MEL it for a problem not directly related to it is an improper use of the MEL. I have encountered this MEL before and since I disagreed with its application I previously called maintenance control; the chief pilot; and the director flight operations - technical. He responded by saying; 'it is a very common practice to MEL an entire system if a component or subsystem is malfunctioning. In this case; the door seal is a component of the pressurization system; which can be deferred. The (O) procedure described in 21-18 instructs pilots to operate unpressurized. For example; there are hundreds of components that make up the APU. If one component is inoperative; the APU is deferred. However; several systems on the aircraft have their individual components broken down in the MEL because the overall system can still be used when an individual component is inoperative. Some examples are egpws; TCAS; & flight crew seats. Although maintenance has a technical bulletin from embraer I don't see much benefit to putting it in the logbook since MEL 21-18 already gives relief of a squealing door seal by flying unpressurized.'

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Original NASA ASRS Text

Title: A First Officer reports on what he believes is an improper use of the MEL to defer the manual and auto pressurization systems on their EMB-145; when in fact; the cabin door pressure seal is the problem.

Narrative: Carrier Maintenance Control used MEL 21-18 to keep the aircraft in service to buy more time to make repairs. Arrived at Aircraft X to operate flight in May 2009. Logbook showed MEL 21-18 auto and manual pressurization inop. When I referenced the logbook page to find the original discrepancy it showed 'service door squeals' I have run into this same situation before and I do not believe this to be a proper use of MEL 21-18 as both the manual and auto pressurization systems were functioning properly. There is no relief in the MEL for a door seal. In my opinion; to deactivate an operable system and then MEL it for a problem not directly related to it is an improper use of the MEL. I have encountered this MEL before and since I disagreed with its application I previously called Maintenance Control; the Chief Pilot; and the Director Flight Operations - Technical. He responded by saying; 'It is a very common practice to MEL an entire system if a component or subsystem is malfunctioning. In this case; the door seal is a component of the pressurization system; which can be deferred. The (O) procedure described in 21-18 instructs pilots to operate unpressurized. For example; there are hundreds of components that make up the APU. If one component is inoperative; the APU is deferred. However; several systems on the aircraft have their individual components broken down in the MEL because the overall system can still be used when an individual component is inoperative. Some examples are EGPWS; TCAS; & Flight Crew Seats. Although maintenance has a technical bulletin from Embraer I don't see much benefit to putting it in the Logbook since MEL 21-18 already gives relief of a squealing door seal by flying unpressurized.'

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.