MMEL

MMEL, short for Master Minimum Equipment List, is a document used in aviation that specifies the minimum equipment and instruments that must be operational for an aircraft to be considered airworthy during flight. It allows for certain non-essential items to be inoperative under specific conditions, thereby providing operational flexibility while maintaining safety standards.

The MMEL is established by the aircraft manufacturer in collaboration with aviation safety authorities such as the Federal Aviation Administration (FAA) in the United States or the European Aviation Safety Agency (EASA) in Europe. It serves as a reference for airlines and operators to develop their own operational procedures, known as the Configuration Deviation List (CDL), which tailor the MMEL to specific aircraft configurations.

The MMEL categorizes equipment based on their criticality and impact on flight safety. Items essential for flight safety are typically required to be operational at all times, whereas certain non-critical systems may be permitted to be inoperative, provided specific operational limitations are adhered to. This flexibility reduces unnecessary ground delays and allows for maintenance planning without compromising overall safety.

Operators must ensure compliance with MMEL guidelines during aircraft operations, and any deviations require proper authorization and documentation. The MMEL is distinct from the Configuration Deviation List, which is an operator-specific document that details allowable inoperative items for individual aircraft.

Overall, the MMEL plays a critical role in balancing operational efficiency and safety in the aviation industry, supporting effective maintenance planning and ensuring the continued airworthiness of aircraft during routine operations.