Minimum Equipment List (MEL) for Pilots: Dispatch, Deferrals, and Maintenance

You’re halfway through your preflight walk-around when you discover the number two landing light is burned out. Your flight is a day VFR cross-country under Part 91. Can you legally depart? The answer depends on whether you know how to use a minimum equipment list — or, if your aircraft doesn’t have one, how to apply the regulatory alternatives that govern dispatch with inoperative equipment.

The MEL is an FAA-approved document that allows operators to dispatch aircraft with certain inoperative items under defined conditions. By the end of this guide, you will understand what an MEL is, how it differs from the MMEL and KOEL, how to apply it step by step during dispatch, and what the FAA requires for compliance.

What Is a Minimum Equipment List?

A minimum equipment list is a structured, FAA-approved document that identifies specific instruments and equipment on an aircraft that may be inoperative at the time of dispatch while still maintaining airworthiness and an acceptable level of safety. It is not a blanket permission to fly with anything broken — it is a controlled, conditional authorization. Each deferral carries specific operational limitations, placarding requirements, and repair timelines.

The MEL originates from the Master Minimum Equipment List (MMEL), which is developed collaboratively by the aircraft manufacturer and the FAA (or the State of Design authority). The MMEL serves as a broad template covering all configurations and operations for a given aircraft type. Operators then customize this template into their own aircraft minimum equipment list, tailoring it to their specific fleet configuration, installed equipment, and operational environment.

Once the operator’s MEL is complete, it must be submitted to and approved by the FAA or the relevant regulatory authority before it can be used for dispatch decisions. This approval process ensures that the operator’s MEL meets or exceeds the safety floor established by the MMEL. The result is a living document — specific to that operator, that fleet, and those operations — that serves as a structured decision-making tool every time a pilot encounters inoperative equipment.

MMEL vs. MEL vs. KOEL: Understanding the Key Differences

Pilots frequently encounter three documents related to inoperative equipment dispatch: the MMEL, the MEL, and the KOEL. Confusing them — or worse, using the wrong one — leads to compliance errors and potential safety risks. Here is how they differ.

What is the difference between an MMEL and an MEL? The MMEL is the manufacturer-level template. The MEL is the operator-level, FAA-approved dispatch document. The MMEL is not directly usable by operators for dispatch — a common and serious misconception.

• Master Minimum Equipment List (MMEL): Developed by the aircraft manufacturer with FAA input. Covers all possible configurations and operations for a type. Serves as the broadest allowable template. Cannot be used directly by operators for dispatch decisions.
• Minimum Equipment List (MEL): Created by the operator, customized from the MMEL to reflect their specific aircraft configuration and operations. Approved by the FAA or relevant authority. Can be equal to or more restrictive than the MMEL — but never less restrictive. Under EASA Regulation 216/2008 Annex IV, this “not less restrictive” requirement is explicitly mandated.
• Kinds of Operations Equipment List (KOEL): Found in the aircraft’s Pilot Operating Handbook (POH). Used primarily by Part 91 operators of small, non-turbine aircraft that do not hold an FAA-approved MEL. The KOEL identifies equipment required for specific kinds of operations — VFR day, VFR night, and IFR.

Do Part 91 small aircraft operators need an FAA-approved MEL? No — not if they use the alternative pathway under 14 CFR 91.213(d). This regulation allows operators of small, non-turbine-powered aircraft to assess dispatch legality using the KOEL, POH equipment lists, and the conditions outlined in that subsection. This is the minimum equipment list for small aircraft Part 91 alternative that most general aviation pilots rely on daily.

FAA Regulatory Framework: 14 CFR 91.213 and FAA MEL Requirements

The regulatory backbone for operating with inoperative equipment is 14 CFR 91.213. This regulation provides two distinct pathways, and understanding both is essential for compliance with FAA MEL requirements.

14 CFR 91.213(a) establishes the primary rule: no person may take off in an aircraft with inoperative instruments or equipment unless the aircraft has an FAA-approved MEL and a Letter of Authorization (LOA) on board. This pathway applies to operators who have developed and gained approval for their operator-specific MEL. The MEL and LOA together constitute the regulatory authority to dispatch with defined deferred maintenance procedures in place.

14 CFR 91.213(d) provides the alternative pathway — and it is the one most relevant to Part 91 operators of small, non-turbine-powered aircraft for which an approved MEL is not in use. Under this subsection, an operator may fly with inoperative equipment if the item is not required by the aircraft’s VFR-day type certificate, is not listed as required on the aircraft’s KOEL or equipment list, is not required by 14 CFR 91.205 or any other applicable Part 91 rule, and is not required by an airworthiness directive. The inoperative item must be placarded and either removed or deactivated.

For comprehensive guidance on applying these FAA MEL requirements, FAA Advisory Circular AC 120-125 is the definitive resource. Pilots and operators working under international frameworks should also be aware that EASA Part ORO.MLR.105 mandates an operator-prepared MEL accounting for the specific aircraft configuration, and EASA Regulation 216/2008 Annex IV requires that the MEL not be less restrictive than the MMEL.

How to Use a Minimum Equipment List: A Step-by-Step Dispatch Procedure

Understanding how to use a minimum equipment list as a pilot means being able to walk through a structured dispatch decision when you find inoperative equipment during preflight. Here is the procedure for aircraft dispatch with inoperative equipment MEL procedures:

1. Identify the inoperative item. During preflight, note the specific piece of equipment that is not functioning. Be precise — the MEL is organized by ATA chapter and specific item.
2. Verify whether the item is listed in the MEL. Open the operator’s approved MEL and locate the item. If it is not listed, stop here: the aircraft cannot dispatch until the item is repaired. There is no deferral authority for unlisted items.
3. Check all conditions for deferral. If the item is listed, review every associated condition. Check operational limitations — is the deferral authorized for IFR? Night operations? Icing conditions? Verify the number required versus the number installed. Review any (O) procedures (operational procedures the crew must follow) and (M) procedures (maintenance procedures required before dispatch).
4. Placard the inoperative item. Placard inoperative equipment as specified in the MEL. This ensures every crew member who flies the aircraft is immediately aware of the deferral.
5. Log the deferral in the aircraft maintenance record. Document the inoperative item, the MEL reference, the date of discovery, and the applicable repair interval category. This starts the clock on the repair deadline.
6. Ensure crew awareness and brief accordingly. The deferral and any associated operational limitations must be part of the crew briefing. Crew awareness is not optional — it is a compliance requirement.
7. If any condition is not met, do not dispatch. The MEL is a conditional authorization. All conditions must be satisfied for legal dispatch.

Operators and maintenance leaders often advise reading the MEL “left to right, top to bottom” — stopping at each inoperative item to determine whether to fix or defer before proceeding.

Scenario 1: Fire extinguishers. Your aircraft has 4 portable fire extinguishers installed. The MEL entry shows that only 2 are required operative. Two extinguishers are inoperative. Dispatch may be legal — provided all MEL conditions are met, including any placement requirements for the remaining operative units.

Scenario 2: Inoperative landing light, day VFR. Returning to our opening scenario — if the aircraft has an approved MEL, check whether the landing light is listed and whether day VFR dispatch is authorized with it inoperative. If the MEL permits the deferral for day VFR with no additional conditions, the flight may proceed after placarding and logging. If the aircraft operates under 14 CFR 91.213(d) instead, verify the landing light is not required by the type certificate, KOEL, 91.205, or any airworthiness directive for VFR-day operations.

MEL Deferral Categories: Repair Intervals A Through D

Every deferred item in the MEL is assigned a repair interval category that defines the maximum time the aircraft may continue to dispatch with that item inoperative. Pilots must track these intervals during flight planning to prevent expiration. These are the minimum equipment list repair interval categories A B C D:

• Category A: A specific time interval defined in the MEL itself. This may require rectification before the next flight, within a set number of flight hours, or within a defined calendar period. The interval is explicitly stated in the MEL entry.
• Category B: 3 consecutive calendar days, excluding the day of discovery.
• Category C: 10 consecutive calendar days, excluding the day of discovery.
• Category D: 120 consecutive calendar days, excluding the day of discovery.

These are maximum intervals. Operators may impose shorter repair timelines based on their operational needs or safety management system. As part of sound deferred maintenance procedures, pilots should verify the status of all open deferrals before every flight — an expired deferral grounds the aircraft until the item is repaired or a new authorization is obtained.

Common MEL Misconceptions Pilots Should Avoid

Misunderstanding the MEL undermines both compliance and safety. These are the most common errors pilots make — and the reality behind each one. Recognizing them is a core component of minimum equipment list training and sound pilot go/no-go decision making.

Myth: “Every aircraft has an MEL.”
Reality: Formal, FAA-approved MELs are primarily associated with commercial and large aircraft operations. Most Part 91 small aircraft operators use the KOEL or POH equipment list pathway under 14 CFR 91.213(d) instead. Do not assume universal applicability.

Myth: “The MMEL is my MEL.”
Reality: The MMEL is a manufacturer-level template. It must be customized by the operator into a fleet-specific MEL and then approved by the FAA. Using the MMEL directly for dispatch is a compliance violation.

Myth: “If it’s inoperative, I can always defer it.”
Reality: Only items explicitly listed in the MEL — with all associated conditions satisfied — may be deferred. If an inoperative item is not in the MEL, the aircraft does not dispatch until that item is repaired.

Myth: “The MEL overrides all other regulations.”
Reality: The MEL interacts with other operational rules. VFR/IFR equipment requirements, icing regulations, and airworthiness directives all remain in effect. An item essential for the planned type of operation must remain operative regardless of what the MEL might allow for other conditions.

MEL Training for Pilots: Building Real-World Decision-Making Skills

MEL proficiency is not reserved for airline captains. For student pilots, understanding minimum equipment list concepts builds regulatory literacy early and clarifies the difference between the MEL framework and basic VFR equipment requirements under 14 CFR 91.205. MEL training for flight school students creates a foundation that pays dividends throughout a flying career.

For commercial and ATP candidates, MEL procedures for pilots proficiency is essential. Multi-crew IFR dispatch decisions demand the ability to evaluate deferrals quickly, brief operational limitations accurately, and recognize when a deferral category is approaching expiration. For flight instructors and training managers, embedding structured, scenario-based MEL curriculum into ground school improves training outcomes measurably.

Scenario-based training is particularly effective. Consider this: “Your attitude indicator fails during preflight for an IFR departure. Walk through your MEL decision tree.” Exercises like this teach not only the regulatory pathway but the critical thinking behind it. The industry’s push toward digital MEL management is accelerating, and e-learning platforms are now integrating interactive MEL simulations that allow pilots to practice deferral decisions in realistic operational contexts.

Ready to master MEL procedures? Explore CTS’s Minimum Equipment List (MEL) training course to build the dispatch decision-making skills every pilot needs. For pilots and operators working under Part 135, CTS’s FAR Part 135 Training packages provide comprehensive regulatory compliance education — including MEL integration into dispatch procedures.

Frequently Asked Questions About the Minimum Equipment List

What is a minimum equipment list and how does it work?
A minimum equipment list is an FAA-approved, operator-specific document that identifies aircraft instruments and equipment permitted to be inoperative at dispatch under defined conditions. It works by providing pilots and dispatchers with a structured reference: if an item is listed, all conditions are met, and the deferral is properly placarded and logged, the aircraft may legally dispatch without that item operative.

What is the difference between an MMEL and an MEL?
The MMEL is a manufacturer-level template developed with FAA input covering all configurations for an aircraft type. The MEL is the operator’s customized version, tailored to their specific fleet and operations, and approved by the FAA. The MMEL cannot be used directly for dispatch; it must be adapted into an operator-specific MEL.

Can a pilot legally fly with inoperative equipment without an MEL?
Yes, under certain conditions. 14 CFR 91.213(d) allows operators of small, non-turbine-powered aircraft to fly with inoperative equipment if the item is not required by the type certificate, KOEL, 14 CFR 91.205, any applicable Part 91 rule, or an airworthiness directive — and if it is placarded inoperative and either removed or deactivated.

What are MEL deferral categories and how long can equipment be deferred?
MEL deferrals fall into four categories: Category A has a specific interval defined in the MEL. Category B allows 3 consecutive calendar days. Category C allows 10 consecutive calendar days. Category D allows 120 consecutive calendar days. Categories B, C, and D all exclude the day of discovery. Operators may impose shorter intervals.

Do Part 91 small aircraft operators need an FAA-approved MEL?
No. Part 91 operators of small, non-turbine aircraft may use the alternative pathway in 14 CFR 91.213(d), relying on the KOEL or POH equipment lists to determine whether dispatch with an inoperative item is permissible. A formal FAA-approved MEL is not required for this pathway.

Strengthening Your Minimum Equipment List Knowledge for Safer Dispatch Decisions

The minimum equipment list is more than a regulatory document — it is a pilot’s practical tool for making safe, legal, and informed dispatch decisions. Mastering MEL logic builds airmanship that transfers across aircraft types, operational environments, and certificate levels. Whether you are evaluating a burned-out landing light on a Cessna 172 or managing multiple deferrals on a transport-category aircraft, the decision-making framework is the same.

Invest in structured minimum equipment list training to move beyond theory and build the proficiency that defines a competent, safety-focused aviator. CTS’s MEL training course provides the scenario-based, interactive instruction that accelerates this proficiency. The relevance of MEL concepts continues to expand — CAP 03 Rev 14, effective June 2025, now extends MEL guidance to Remotely Piloted Aircraft under CAR OPS 4.806, reinforcing that structured dispatch decision-making is foundational to the future of aviation, not only its present.