FAR Ninety-One Point Two Thirteen, the Inoperative Equipment Decision, and the Four Questions Every Pilot Has to Work Through Before Engine Start

FAR 91.213 provides a structured, four-condition decision process for evaluating inoperative equipment - not a blanket prohibition and not a free pass, but a logical framework tied specifically to the kind of operation being conducted. Most general aviation pilots either ground themselves unnecessarily when something breaks or fly with equipment that should have kept them on the ramp. Knowing this regulation in detail eliminates the guesswork.

Are You on the MEL Track or the 91.213(d) Track?

When a piece of equipment stops working, you are immediately on one of two tracks.

Track one applies if your aircraft has a Minimum Equipment List (MEL) - an FAA-approved document specifying which systems can be inoperative under defined conditions and still permit legal flight. MELs are common in transport category, airline, and charter operations. If your aircraft has an MEL, you follow the MEL, and that is where the analysis ends.

Track two is where most general aviation pilots operate. Aircraft like the Cessna 172, Piper Cherokee, and Beechcraft Bonanza typically do not have MELs. Without one, FAR 91.213(d) provides the governing framework: four conditions that must all be satisfied before you can deactivate inoperative equipment and conduct a legal flight. Do not mix the two tracks.

What Are the Four Conditions Under FAR 91.213(d)?

Work through these conditions in order. All four must be satisfied for the specific kind of operation you intend to conduct.

Condition 1: Type Certification Requirements

The inoperative equipment must not be required by the airworthiness regulations under which the aircraft was type certificated. When the FAA certified your aircraft type, certain instruments and equipment were mandated as part of making it airworthy. If the broken item is on that list, it requires a maintenance action - full stop.

This information lives in the type certificate data sheet (TCDS), a public FAA document available through the FAA website under aircraft certification records or in the aircraft’s permanent file. Know where this document is and what it contains before any checkride.

Condition 2: Aircraft Equipment List and KOEL

The inoperative equipment must not be listed on the aircraft’s equipment list or its Kinds of Operations Equipment List (KOEL) for the kind of flight you are planning. The KOEL, typically found in Section 6 or Section 7 of the Pilot’s Operating Handbook (POH), specifies what is required for day VFR, night VFR, and IFR operations.

Not every POH uses the term “KOEL,” but most include an equipment list organized by operational category. This list varies by aircraft type and by individual serial number - what is required for one airplane may not be required for another with the same make and model. You must read your specific airplane’s POH, not rely on what another pilot tells you about a different aircraft.

Condition 3: FAR 91.205 and Other Part 91 Rules

The inoperative equipment must not be required by FAR 91.205 or any other Part 91 rule for the specific kind of flight you intend to conduct. This condition resolves most practical scenarios quickly.

For day VFR, FAR 91.205 requires:

• Tachometer for each engine
• Oil pressure gauge for each engine using a pressure system
• Manifold pressure gauge for each altitude engine
• Fuel gauge indicating quantity in each tank
• Landing gear position indicator (retractable gear aircraft only)
• Anti-collision light system (aircraft certified after March 19, 1996)
• Safety belt for each occupant
• Emergency Locator Transmitter (with limited exceptions)
• Airspeed indicator
• Altimeter
• Magnetic direction indicator (compass)

The attitude indicator, directional gyro, and turn coordinator are not on the day VFR list. If one of those fails and it clears the other three conditions, a day VFR flight is legally permissible without it.

For night VFR, the regulation adds approved position lights (nav lights), an approved anti-collision light system, adequate electrical energy for all installed equipment, spare fuses, and a landing light - but only if the aircraft is operated for hire. A private pilot flying their own aircraft at night with no compensation involved is not legally required under 91.205 to have a working landing light. Operationally, you want one every time. Legally, the requirement attaches only when passengers are carried for compensation or hire.

For IFR, the required equipment list expands to include: a gyroscopic rate-of-turn indicator, a slip-skid indicator (ball/inclinometer), a sensitive altimeter adjustable for barometric pressure, a clock displaying seconds, a generator or alternator of adequate capacity, a gyroscopic pitch and bank indicator (attitude indicator), a gyroscopic direction indicator (directional gyro or HSI), and appropriate communications and navigation equipment for the facilities and procedures being used.

If a turn coordinator is inoperative and an IFR flight is planned, condition three fails immediately. A gyroscopic rate-of-turn indicator is required for IFR, and a turn coordinator qualifies as one. The flight does not depart until the aircraft is repaired.

Condition 4: Airworthiness Directives

The inoperative equipment must not be required to be operational by an Airworthiness Directive (AD). ADs are mandatory FAA requirements. If an applicable AD requires the equipment to be operational, it overrides everything else - the aircraft stays on the ground. Check the maintenance records and the FAA’s AD database whenever there is any uncertainty.

What Happens After All Four Conditions Are Satisfied?

If the inoperative equipment clears all four conditions for the intended operation, FAR 91.213(d) provides two options for proceeding legally.

Option 1 - Removal: Have the equipment physically removed from the aircraft and the cockpit control placarded. Removal is a maintenance action under FAR Part 43, requiring a properly certificated mechanic to perform the work and make a logbook entry.

Option 2 - Deactivation and Placarding: Deactivate the equipment and affix a placard reading “INOPERATIVE” directly on or adjacent to the instrument. This placard is a regulatory requirement, not a suggestion.

Whether the pilot can perform the deactivation or whether a mechanic is required depends on what deactivation involves. Pulling a circuit breaker and collaring it so it cannot be accidentally reset, or securing a switch in the off position, generally does not constitute a maintenance action if the pilot can accomplish it without touching anything that falls under Part 43. If deactivation requires maintenance work, a certificated mechanic must perform and log it.

After deactivating and placarding, the pilot in command must make a final determination that the inoperative equipment does not constitute a hazard to the aircraft. That judgment belongs to the PIC - not the mechanic, not the FBO manager, not another pilot on the ramp. The regulation authorizes the flight; the PIC’s judgment approves it. If something feels operationally unsound even after all four conditions are satisfied, the pilot is never obligated to go.

A Full Worked Example: Attitude Indicator in a Cessna 172

Scenario: You are a private pilot planning a day VFR cross-country in a Cessna 172. On preflight, the attitude indicator has tumbled and is not erecting.

• Condition 1: Is the attitude indicator required by the Cessna 172’s type certification airworthiness requirements? For most 172 certifications, no.
• Condition 2: Does your specific aircraft’s POH or equipment list require the attitude indicator for day VFR? Read the document. Most Cessna 172 POHs do not list it as required for day VFR operations.
• Condition 3: Is the attitude indicator required by FAR 91.205 for day VFR? No. It is required for IFR; it does not appear on the day VFR list.
• Condition 4: Is there an applicable AD requiring it to be operational? Assuming none exists, all four conditions are satisfied.

Result: Deactivate the instrument - pull and collar the relevant circuit breaker, or otherwise secure it without maintenance. Placard the instrument face “INOPERATIVE.” Make your PIC determination that a clear-day VFR flight to an airport 40 miles away does not constitute a hazard to this aircraft. The flight is legal.

Now change one variable: the weather deteriorates and you want to file IFR to the same destination.

• Condition 3 (IFR): Is the attitude indicator required by FAR 91.205 for IFR? Yes - a gyroscopic pitch and bank indicator is explicitly listed on the IFR equipment list.

Condition three fails. The IFR flight does not happen until the aircraft is repaired. Same airplane. Same broken instrument. Two different legal outcomes - determined entirely by the kind of operation being conducted. That is the design of the regulation.

Do I Need a Logbook Entry When I Deactivate an Inoperative Item?

If deactivation involves maintenance, a certificated mechanic performs and logs the work under Part 43. If deactivation does not involve maintenance and the pilot performs it themselves, FAR 91.213 alone does not explicitly require a maintenance logbook entry. However, many flight schools, clubs, and aircraft owners require one as a matter of policy - and for sound operational reasons.

Regardless of what is formally required in your specific operation, the next pilot to fly that aircraft must be able to clearly see the “INOPERATIVE” placard and understand the equipment status before departure. That communication is part of responsible PIC behavior.

How Do Examiners Test This on the Checkride?

Expect the Designated Pilot Examiner (DPE) to present a broken-equipment scenario and ask you to work through it aloud. They are not looking for a yes-or-no answer - they want to observe the decision-making process.

Walk through the logic in this sequence:

1. Check for an applicable Airworthiness Directive
2. Check the type certificate data sheet for type certification airworthiness requirements
3. Check the equipment list or KOEL in the POH for the intended kind of operation
4. Check FAR 91.205 for the specific kind of flight

The Airman Certification Standards (ACS) for private pilot address required instruments and equipment, including inoperative equipment scenarios. Know the day VFR equipment list cold. Know what is added for night VFR. Know what is added again for IFR. Apply the framework to a specific scenario on the spot without hesitation.

Key Takeaways

• FAR 91.213(d) is the four-condition inoperative equipment framework for general aviation aircraft without an MEL - all four conditions must be satisfied before deactivating equipment and flying.
• The legality of flying with inoperative equipment depends entirely on the kind of operation being conducted - the same broken instrument can be a non-issue for day VFR and a hard stop for IFR.
• The “INOPERATIVE” placard on or adjacent to the instrument is a regulatory requirement under FAR 91.213, not optional.
• Whether a pilot or mechanic must perform the deactivation depends on whether the deactivation itself constitutes a maintenance action under Part 43.
• The pilot in command makes the final safety determination - regulatory authorization does not obligate the PIC to fly.