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Maintenance: Understanding Minimum Equipment Lists

How much do you know about your aircraft’s minimum equipment list (MEL)? You may not want to answer until you read this article.

An MEL is the list of equipment that may be inoperative, yet still allow an aircraft to operate safely, per FAA regulations. Referring to the MEL also helps operators determine the impact of flying with inoperative systems.

So how is an MEL created? Each aircraft’s MEL evolves from the master minimum equipment list (MMEL) provided by the OEM and approved by the FAA.

“The MMEL includes all equipment and accessories available for the aircraft model, while the MEL is created by the operator for your specific type of aircraft.”

Elaine Karabatsos Director of Aviation Maintenance, Encompass Health

“The MMEL includes all equipment and accessories available for the aircraft model, while the MEL is created by the operator for your specific type of aircraft,” said Elaine Karabatsos, aviation maintenance director for Encompass Health. “If you’re flying serial number 15, you’re going to customize your MEL for the equipment on your aircraft that may not be present on serial number seven.”

Part 121, 125, 135 and Part 91 Subpart K operators are authorized to use an FAA-approved MEL in accordance with OpSpec D095, or MSpec D095 for Subpart K, said Tom Atzert of Leading Edge Aviation Technical Services. “Part 91 operators must apply for an FAA letter of authorization to operate using an MEL in accordance with either D095 or D195,” explained Atzert.

Besides ensuring safety, a properly updated MEL helps operators avoid non-compliance, so it’s important to keep MELs up-to-date following changes to equipment or documentation made by the operator, the manufacturer or the FAA.

“I just received notice of a revision for one of our aircraft, and it’s open right now for public comment,” said Greg Hamelink, senior manager for flight operations and maintenance at Stryker Corp. “In addition to having forewarning that a revision is imminent, you may also be able to provide comments back to the FAA on any changes they might make.”

Proper coordination between the OEM, operator and the local FSDO for approval of MEL changes is important. “It really pays to keep an eye on what your manufacturer is doing and try to get ahead of those revisions,” said Hamelink.

To learn more about minimum equipment lists, visit

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