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NBAA Provides Update on Part 91 Draft MEL AC

Minimum equipment lists (MELs), should be one of the simplest aspects of a Part 91 operator’s routine, but in fact, they can be some of the most confusing. Why? Well, much of the confusion stems from the simple fact that there hasn’t been an updated advisory circular (AC) for a long time. A lot has changed over the years.

“Today, with no advisory material written to aid operators in the creation of MELs, we’ve been essentially forced to use FAA inspector guidance material in 8900.1. Volume 4, Chapter 4, Sections 1 thru 4,” explained Tom Atzert, president of Leading Edge ATS. “Unfortunately, that material is vague in some areas and prone to individual inspector interpretation, leading to disagreements as to whether or not the MEL content was approvable or needed to be rewritten according to FAA findings/comments.”

“The current information doesn’t provide enough guidance for operators truly trying to grasp everything related to MELs.”

Greg Hamelink Director Business Travel Center for Whirlpool

“The current information doesn’t provide enough guidance for operators truly trying to grasp everything related to MELs,” added Greg Hamelink, director, Business Travel Center for Whirlpool. “There were many ambiguities with STCs, policy letters, and global change documents that should be addressed when the updated AC becomes available.”

To help provide better MEL guidance, the FAA introduced a draft of AC 91-67A and has accepted comments from Part 91, 133 and 137 operators.

“The FAA’s proposed AC provides more comprehensive and better direction for Part 91 on how to implement a MEL as part of their operations and be compliant with FAA and ICAO requirements,” said Brian Koester, CAM, and NBAA’s director of flight operations and regulations. “The FAA reinforced their belief that the original AC instructions for D195 and DO95 MELs met ICAO standards.”

“NBAA believes that both ways can be compliant,” he added. “And it’s important for operators to have all of the required components for a MEL in order to ensure they are.”

“The big-picture perspective with the AC 91-67A update was that the two MELs (D095 and D195) are available for Part 91 operators. This draft keeps both options, which provides continuity for operators,” Hamelink said. “One heartburn for international operators was a SAFA [Safety Assessment for Foreign Aircraft] performed in Europe was found not to have ‘approved’ MEL D195, but rather ‘accepted’ MEL D095.”

With regard to international operations, while both D095 and D195 LOAs will remain an option, D0195 is the best practice option for avoiding SAFA findings.

“The advisory material in AC 91-67A provides much-needed clarification of all aspects of specific MEL authorizing guidelines,” Atzert said. “It will improve both the quality of the MEL and streamline the FAA review and approval processes.”

Review additional guidance from NBAA at

Industry Challenge:

FAA has concluded its process of gathering responses from Part 91 operators on changes to draft AC-91-67A regarding instructions for MEL lists.

NBAA Response:

NBAA is coordinating closely with the FAA, EASA, and NBAA Part 91 operator members to help create an updated AC that provides much-needed clarification of all aspects of a specific MEL and improves the FAA review/approval process.

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