Sofema Online (SOL) www.sofemaonline.com considers the MMEL Development Process

Introduction

The MMEL is a document issued by the aircraft's original equipment manufacturer (OEM) that lists equipment and systems that may be inoperative for certain flight conditions. Each item on the MMEL is associated with a specific operational procedure to ensure safety during the flight. The MMEL is a critical part of an aircraft's operational certification and is a reference for creating an airline's Minimum Equipment List (MEL).

Creating a Master Minimum Equipment List (MMEL) for a new aircraft is a complex and lengthy process that requires a deep understanding of the aircraft's systems, operation, and safety principles. The aircraft manufacturer designs and tests the aircraft, taking into account various scenarios including situations where certain components or systems might not be operational. These tests will inform the initial draft of the MMEL.

For EASA regulatory environment we must consider Operational Suitability Data (OSD) which is a group of interconnected data elements that are necessary to demonstrate the operational suitability of an aircraft type.

The OSD is part of the aircraft type certification and includes, among other things, the Master Minimum Equipment List (MMEL).

Comment by Steven Bentley MD of Sofema Aviation Services

What are PMA Parts?

For more than 50 years the Federal Aviation Administration (FAA) has been granting Parts Manufacturer Approval (PMA) to allow third-party manufacturing organisations to produce replacement parts for aircraft (Means parts that are usually not produced with the permission of the Original Equipment Manufacturer - OEM).

To quote the FAA PMA which standards for Parts Manufacturer Approval is in fact a combined design and production approval which is issued for the production of modification or replacement parts, which includes materials, parts, processes and appliances.

A primary consideration is that you must not infringe upon any product patents.
A PMA approval allows you to fit the part to an aircraft as a replacement for the original part, off course the part must be every bit as safe as the original part and this needs to be demonstrated to the approving authority for example the FAA.