Understanding MEL, KOEL, and FAR 91.205: Key Differences The Minimum Equipment List (MEL), Kinds of Operations Equipment List (KOEL), and FAR 91.205 are critical components in determining aircraft airworthiness and operational requirements under U.S. FAA regulations. Below is a concise explanation of each and their differences.
1. Minimum Equipment List (MEL) Definition: An FAA-approved, aircraft-specific document allowing operators to dispatch an aircraft with certain inoperative instruments or equipment, provided specific safety conditions and procedures are followed. Derived from the Master Minimum Equipment List (MMEL). Purpose: Enables flexibility for operators to continue operations with non-critical inoperative equipment, typically for turbine-powered aircraft or Part 121/135 operations. Scope: Tailored to a specific aircraft’s make, model, and serial number. Requires a Letter of Authorization (LOA) from the FAA. Applicability: Common for complex aircraft and commercial operations. Rare for small, non-turbine Part 91 aircraft. Example: An MEL might permit flying with an inoperative autopilot if additional crew vigilance is ensured. 2. Kinds of Operations Equipment List (KOEL) Definition: A manufacturer-provided list in the aircraft’s Pilot Operating Handbook (POH) or Aircraft Flight Manual (AFM), specifying equipment required for different flight operations (e.g., VFR day, VFR night, IFR). Purpose: Guides pilots in determining airworthiness for specific flight types based on equipment status (required, standard, or optional). Scope: Aircraft model-specific, included in certification documents, no separate FAA approval needed. Applicability: Common for general aviation, especially non-turbine Part 91 aircraft. Example: A KOEL may require position lights for night VFR but not for day VFR. 3. FAR 91.205 Definition: A regulation under 14 CFR Part 91 listing minimum instruments and equipment for powered civil aircraft with standard airworthiness certificates for VFR or IFR operations, day or night. Purpose: Establishes a baseline for safe flight operations, applicable to all Part 91 aircraft. Scope: Universal for Part 91 aircraft, covering essentials like airspeed indicators and altimeters (e.g., “A TOMATO FLAMES” for VFR day). Applicability: Mandatory unless an MEL or exemption (e.g., Special Flight Permit) applies. Example: Requires an altimeter for all flights, regardless of operation type. Key Differences Aspect MEL KOEL FAR 91.205 Definition FAA-approved list for inoperative equipment. Manufacturer list for operation-specific equipment. Regulation for minimum required equipment. Scope Aircraft- and operator-specific. Aircraft model-specific, in POH/AFM. Universal for Part 91 aircraft. Approval Requires FAA LOA. No separate approval, part of aircraft certification. Regulatory standard, no approval needed. Applicability Turbine aircraft, Part 121/135, or Part 91 with LOA. General aviation, non-turbine Part 91 aircraft. All Part 91 aircraft with standard certificates. Purpose Allows dispatch with inoperative equipment under conditions. Specifies equipment for flight types. Sets minimum safety standards. Precedence Highest priority if it exists. Used if no MEL; supplements FAR 91.205. Baseline if no MEL or KOEL applies. Example Defers inoperative radio with procedures. Requires strobes for night VFR. Requires altimeter for all flights. Precedence and Application Order of Precedence: MEL takes precedence if it exists. Without an MEL, KOEL (if provided) and FAR 91.205 apply. If neither exists, FAR 91.205, Type Certificate Data Sheet (TCDS), and Airworthiness Directives (ADs) govern. Inoperative Equipment: Without an MEL, FAR 91.213(d) allows operation with inoperative equipment not required by KOEL, FAR 91.205, TCDS, or ADs, if deactivated, placarded “Inoperative,” logged, and deemed safe. Practical Example Scenario: Preflighting a Cessna 172 for day VFR with an inoperative navigation radio.
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