FAR Ninety-One Point Two Thirteen, the Inoperative Equipment Decision, and the Four Steps That Tell You Whether to Fly or Stay on the Ground

When you find inoperative equipment during preflight, the question is rarely obvious: cancel the flight, or does the regulation permit you to continue? FAR 91.213 provides a structured, four-question decision framework that tells you exactly how to evaluate any broken item. It’s one of the most tested topics on the private pilot oral exam - and one of the most misunderstood.

Why Does FAR 91.213 Exist?

Aircraft break. Equipment fails at inconvenient times, and the question of whether a broken item makes an airplane unairworthy is not always obvious. The regulation balances two competing concerns: ensuring genuinely critical equipment is operational, and avoiding unnecessary grounding of aircraft over non-essential failures.

Both bad outcomes carry real consequences. Flying with a broken required item is an airworthiness violation - and potentially dangerous. Cancelling a perfectly legal flight because you didn’t know how to evaluate the failure costs time, money, and confidence. The four-question framework eliminates both errors.

What Are the Four Steps of FAR 91.213?

Work through these questions in order. If any question produces a no-go, stop there. If you complete all four without a stop signal, the flight may be legal - with two additional steps before departure.

Question 1: Is the item required by FAR 91.205 for the planned operation? Question 2: Is the item required by the aircraft’s Kinds of Operations Equipment List (KOEL)? Question 3: Does the aircraft have an approved Minimum Equipment List (MEL), and does it address this item? Question 4: Is the item required by an Airworthiness Directive (AD) or any other FAA regulation?

What Equipment Is Required for Day VFR?

FAR 91.205 establishes the minimum equipment requirements for civil aircraft operating under Part 91. Required items differ by operation type: day VFR, night VFR, and IFR.

For day VFR, most instructors teach the mnemonic ATOMATOFLAMES - thirteen letters, thirteen items:

• A - Altimeter
• T - Tachometer (each engine)
• O - Oil pressure gauge
• M - Magnetic direction indicator (compass)
• A - Airspeed indicator
• T - Temperature gauge (liquid-cooled engines)
• O - Oil temperature gauge (air-cooled engines)
• F - Fuel gauge (each tank)
• L - Landing gear position indicator (retractable gear aircraft only)
• A - Anti-collision lights (aircraft certified after March 11, 1996)
• M - Manifold pressure gauge (altitude engines)
• E - Emergency locator transmitter (ELT)
• S - Safety belts (all occupants)

If the inoperative item appears on this list, Question 1 is answered: no-go. Write it up, notify maintenance, and find another solution.

What Additional Equipment Is Required for Night VFR?

Night VFR operations require everything on the day VFR list plus a second set of items, commonly taught with the mnemonic FLAPS:

• F - Fuses (spare set of correct fuses for any circuit not using circuit breakers)
• L - Landing light (required only when operating for hire)
• A - Anti-collision lights
• P - Position lights (red, green, and white navigation lights)
• S - Source of adequate electrical energy for all installed electrical equipment

For night VFR, both ATOMATOFLAMES and FLAPS apply. For day VFR, only ATOMATOFLAMES.

What Is the KOEL and How Do You Use It?

The Kinds of Operations Equipment List (KOEL) lives in the aircraft’s Airplane Flight Manual (AFM) or Pilot’s Operating Handbook (POH). Many pilots know their POH well for performance data and weight and balance - far fewer have read the KOEL.

The KOEL is structured as a table identifying installed equipment and specifying whether each item is required for day VFR, night VFR, or IFR. These requirements were determined by the manufacturer during FAA certification. A manufacturer can make the KOEL more restrictive than FAR 91.205 - if the KOEL designates an item as required, that’s an airworthiness determination that cannot be set aside.

In a Cessna 172, the KOEL is typically in Section Two (Limitations) of the POH. In other aircraft it may be in an appendix. The critical habit is knowing where to find it before you need it - the ramp during preflight is not the time to search page by page through an unfamiliar handbook.

The Airman Certification Standards (ACS) are explicit on this point: if an examiner presents an inoperative equipment scenario during the oral exam, they expect you to physically locate the KOEL in the POH and read it - not recite the answer from memory. Demonstrating the process is the skill being evaluated.

Does Your Aircraft Have an Approved MEL?

A Minimum Equipment List (MEL) is an FAA-approved document specific to an individual aircraft. It identifies certain inoperative items that are permitted under defined conditions - sometimes requiring a placard, a maintenance inspection, or a restriction on permitted operations.

For most general aviation pilots, the practical answer is: your training aircraft almost certainly does not have an MEL. MELs are common in airline, charter, and corporate flight operations. Maintaining an MEL requires an ongoing FAA approval process that the typical flight school Cessna or Piper does not go through.

If an MEL exists and addresses the item, follow its requirements exactly. If the item is not covered in the MEL, or if the MEL says no-go, Question 3 stops the flight.

Could an Airworthiness Directive Ground the Airplane?

Airworthiness Directives (ADs) are legally binding FAA documents issued when an unsafe condition is found in a certificated product. If an AD requires a piece of equipment to be functional, nothing overrides it - not the equipment lists, not the KOEL, not the absence of an MEL.

Verify AD compliance through the aircraft’s maintenance records and AD compliance log. If you’re uncertain, ask an A&P (Airframe and Powerplant mechanic) before flying. ADs apply to avionics, fuel system components, and instruments. This step is not a formality.

What Happens If You’ve Cleared All Four Questions?

If all four questions produced no stop signals, the flight may be legal. Two steps remain before departure.

Deactivate the item. Equipment that doesn’t work should not be left in a state where a pilot might inadvertently trust it. For electrical items, pulling the circuit breaker is usually the cleanest approach. If the item has no electrical component and can’t be physically removed without significant disassembly, document that and proceed. If an A&P can remove it entirely, that’s always a valid option.

Placard it INOPERATIVE. FAR 91.213 requires a placard reading INOPERATIVE placed in plain sight of the crew. This is not optional. A piece of tape marked INOP satisfies the requirement - the regulation is not prescriptive about materials, only about visibility and legibility. The placard prevents in-flight confusion and alerts the next pilot before the repair is made.

How Does This Process Play Out in Real Scenarios?

Scenario 1 - Clock inoperative (Day VFR): Clock is not in ATOMATOFLAMES. Not listed as required in the KOEL for day VFR. No MEL. No applicable AD. Placard it INOPERATIVE. You fly.

Scenario 2 - Oil pressure gauge inoperative (Day VFR): Oil pressure gauge is the O in ATOMATOFLAMES - a required instrument. Question 1 says no-go. Write it up, notify maintenance. This airplane stays on the ground.

Scenario 3 - Map light fails (Night VFR): Map light is not in the FLAPS list. Not listed as required in the KOEL. No MEL. No applicable AD. Technically legal by all four questions - but pause before assuming you’re cleared to go. FAR 91.3 makes you responsible for the safety of the flight, not just its legality. Can you navigate safely at night without a map light? Do you have a backup light or a tablet with charts? Legal and safe are two separate standards. As pilot in command, you own both.

Scenario 4 - Turn coordinator inoperative (Day VFR): The turn coordinator is prominent in the cockpit, which surprises many students. For day VFR, it is not on the FAR 91.205 required list. In many common training aircraft, the KOEL does not list it as required for day VFR either. Work through all four questions. If none produce a stop signal, deactivate if possible, placard it INOPERATIVE, and you can fly day VFR.

This last scenario is a common oral exam question. The examiner wants to watch you open the POH, find the KOEL, and read it - not hear you recite the answer. That demonstrated process is what passing looks like.

What Happens After the Flight?

Flying with inoperative equipment does not close the loop. After any such flight, document the item in the aircraft discrepancy log or the write-up system that applies to that aircraft. The item requires repair before the aircraft returns to full operational status. That write-up starts the maintenance chain and protects every pilot who flies the airplane before the repair is complete.

Key Takeaways

• FAR 91.213 provides a four-question framework - work through them in order and stop at the first no-go signal.
• ATOMATOFLAMES covers the 13 required items for day VFR; FLAPS adds the requirements for night VFR.
• The KOEL in the aircraft’s POH can be more restrictive than FAR 91.205 - always check it, and know where to find it before you need it.
• If an item clears all four questions, deactivate it if possible and placard it INOPERATIVE before flight.
• Legal and safe are separate standards. FAR 91.3 makes you responsible for both.