FAR Ninety-One Point Two Thirteen, the Inoperative Equipment Decision That Trips Up Every Checkride Candidate, and the Four Steps That Tell You Whether You Can Legally Fly

FAR 91.213 gives pilots a structured, legally defensible way to answer one of the most common questions in general aviation: can I fly with this broken? The regulation applies whether you discover a discrepancy on preflight or experience a failure in flight, and working through it correctly is a required skill on every private pilot checkride.

What Is FAR 91.213 and Why Does It Exist?

The FAA wrote 91.213 around a simple truth: aircraft are mechanical, and mechanical things fail. Not every failure is equal. A frozen clock and a frozen attitude indicator represent completely different safety implications.

The regulation provides a legal pathway - not a blank check - for making the fly-or-no-fly decision systematically. If you work through the process correctly and the answers come out in the right direction, you have legal authority to fly. If they don’t, you don’t.

What Are the Four Steps of FAR 91.213?

The process has four steps. The order matters. Do not skip ahead.

Step 1: Does the aircraft have a Minimum Equipment List (MEL)?

An MEL is an FAA-approved document, specific to a tail number, that authorizes an operator to dispatch with certain equipment inoperative. Airlines, Part 135 operators, and some Part 91 Subpart K corporate flight departments have them. If the broken item appears in the MEL, you follow the MEL - including any required procedures or operational limitations. If the broken item is not in the MEL, the MEL grounds you on that item.

The practical reality: most small general aviation aircraft - Cessna 172s, Piper Archers, Diamond DA-20s - do not have MELs. MELs are expensive to develop and require ongoing FAA coordination. If you’re flying a flight school rental or club aircraft, there almost certainly isn’t one. No MEL? Move to Step 2.

Step 2: Is the item listed in the Kinds of Operations Equipment List (KOEL)?

This is the step most pilots skip. Don’t skip it.

The KOEL is a table - found in an appendix of the Pilot Operating Handbook (POH) or Approved Flight Manual - that categorizes equipment as required for day VFR, night VFR, or IFR operations. Newer aircraft are required to have one. Older aircraft may or may not. Know your specific aircraft.

The KOEL carries legal weight through the aircraft’s type certificate. When Cessna or Cirrus or Piper declares in approved documentation that a piece of equipment is required for a given kind of operation, you cannot go below that standard - even if it exceeds the FAA’s general equipment list. Some aircraft list the stall warning system as required for all operations in the KOEL. It’s not on FAR 91.205’s day VFR list. But if the manufacturer requires it in that aircraft, it’s required.

If the KOEL lists the broken item as required for the kind of operation you’re planning, fix it or change the operation. An item required for IFR doesn’t necessarily ground a day VFR flight - but you need to know which column it falls in. If the KOEL doesn’t list it as required, or there’s no KOEL, move to Step 3.

Step 3: Is the item required by FAR 91.205?

FAR 91.205 is the required equipment list for powered civil aircraft. This is where the training mnemonics live.

For day VFR, required equipment includes:

• Airspeed indicator
• Tachometer for each engine
• Oil pressure gauge
• Temperature gauge (liquid-cooled engines) / oil temperature gauge (air-cooled engines)
• Manifold pressure gauge (altitude engines)
• Fuel gauges for each tank
• Landing gear position indicator (retractable gear)
• Safety belts
• ELT (where required)
• Anticollision lights (aircraft certified after March 1996)
• Magnetic direction indicator (compass)

Your compass fails? You cannot legally fly day VFR.

For night VFR, add: position lights, an adequate source of electrical energy, one spare set of fuses or three fuses of each kind required, and an approved anticollision light system.

For IFR, add: attitude indicator, heading indicator or gyroscopic direction indicator, slip-skid indicator, sensitive altimeter adjustable for barometric pressure, a clock displaying hours/minutes/seconds, a generator or alternator of adequate capacity, and DME or radio navigation equipment for applicable high-altitude routes.

On the IFR clock requirement: the regulation requires a clock showing hours, minutes, and seconds with a sweep second hand or digital display. It does not specify a panel-mounted clock. A wristwatch with a digital seconds display or sweep second hand legally satisfies the requirement. If your panel clock fails, check your wrist before deciding you’re IFR-grounded.

If the broken item appears on the 91.205 list for your planned operation, you cannot legally fly without it - unless you can satisfy the requirement another way.

Step 4: Is the item required by an Airworthiness Directive or other specific airworthiness requirement?

Airworthiness Directives (ADs) are issued when the FAA determines an unsafe condition exists in an aircraft type, engine, propeller, or appliance. They are legally enforceable. If an AD requires a piece of equipment to be operative, the aircraft is not airworthy without it. That’s the end of the analysis.

Know the ADs applicable to your aircraft. Your maintenance records should reflect AD compliance. When in doubt with a rental, ask the maintenance operation directly.

What Happens When All Four Steps Come Back “No”?

If none of the four steps produce a requirement - no MEL restriction, not listed in the KOEL for this operation, not on the 91.205 list for this flight, no applicable AD - then 91.213 permits you to fly.

Two conditions apply.

First, the inoperative item must be deactivated or removed. If it’s electrically powered, pull the circuit breaker. If it has a mechanical function, secure it so it cannot interfere with safe operation.

Second, it must be placarded. A placard visible to the pilot in command, reading “inoperative.” Not a sticky note - a proper placard.

The placard serves a real function. The next pilot sees it. The CFI doing a checkout sees it. The maintenance technician at the next inspection sees it and knows it’s a known squawk. The DPE on checkride day sees it and asks about it. It closes a loop that needs to stay closed.

How Does This Apply to a Real Scenario - The Frozen VSI?

Take a frozen vertical speed indicator (VSI) on a day VFR preflight. No MEL. You open the POH - the VSI is not listed as required for day VFR in the KOEL. You check 91.205 - the VSI is not on the day VFR required equipment list. No applicable AD. You can legally fly.

Pull the circuit breaker if there is one, note the squawk in the maintenance records, put up the placard, and plan your descents without that reference.

Now change one variable: you’re flying IFR. Check the KOEL again. Some aircraft list the VSI as required for IFR operations. If it’s there, you’re grounded for IFR - regardless of what the general regulatory minimum says. The manufacturer’s determination controls.

What About a Failed Transponder?

The transponder is a common source of confusion because it’s governed by FAR 91.215, not 91.205. Required transponder operation applies in:

• Class A, B, and C airspace
• Within 30 nautical miles of a Class B primary airport (the Mode C veil)
• Above 10,000 feet MSL in Class E airspace

A failed transponder does not automatically ground you everywhere. Flying VFR in Class E or Class G airspace outside the Mode C veil, below 10,000 feet, is legal without a transponder. But once your route passes through those protected areas, you need ATC authorization. ATC can sometimes accommodate an in-flight transponder failure. Departing deliberately into a Mode C veil with a known inoperative transponder is a different situation. Understand the geography before making the call.

What If Equipment Fails In Flight?

FAR 91.213 applies to in-flight failures the same way it applies to preflight discoveries. If a fuel gauge stops reading during cruise, work through the same four steps. If the analysis permits you to continue, continue - and plan accordingly.

The priority order matters here: stabilize the airplane first, then assess the impact, then make the decision. The pilot focused on the decision tree before flying the airplane has the priorities backward.

For IFR flights, a failure that affects a required approach item narrows your options quickly. A divert to alternate conditions, or ATC assistance, may become necessary. Think through destination requirements before declaring the item manageable.

What Are the Maintenance Record Requirements?

When you find a squawk and legally fly under 91.213, note it in the maintenance records. The discrepancy should be documented. When a certificated mechanic or repairman signs off the repair, the placard comes down. Until then, it stays up.

Flying with the same placard up week after week, with no maintenance entry and no progress toward a fix, is not what the regulation intended. The maintenance loop needs to stay active.

How Do You Answer This on a Checkride?

The ACS requires private pilot applicants to determine aircraft airworthiness and demonstrate knowledge of applicable regulations. A DPE may hand you a list of squawked items and ask you to work through them.

The answer is never just yes or no. The answer is a process:

1. Check whether the aircraft has an MEL - and whether this item appears in it
2. Check the KOEL in the POH for the planned kind of operation
3. Check FAR 91.205 for the required equipment list
4. Verify there is no applicable AD

If all four come back negative, the item must be deactivated and placarded before flight.

That walkthrough, delivered in order and without hesitation, is what earns the passing grade. The examiner is evaluating systematic thinking, not perfect memorization.

Legal vs. Safe: Knowing the Difference

FAR 91.213 gives legal permission to fly with certain inoperative equipment. That is not a safety endorsement. Regulations are a floor, not a ceiling.

A VSI that’s been acting up on an IFR aircraft might be legally deferrable while a part is on order - but if the weather is marginal and the approach will be demanding, fixing it first is the right call. A fuel gauge reading unreliably might not ground you legally, but fuel planning needs to fully account for that uncertainty. When a gap exists between legal and safe, close it before flying.

Your primary regulatory sources: Title 14 of the Code of Federal Regulations, specifically FAR 91.205 and FAR 91.213. Your POH - particularly the KOEL - is the most critical document in this process, and most pilots have never located it in their aircraft. Find it before you need it.

Key Takeaways

• FAR 91.213 provides a four-step legal framework: check the MEL, the KOEL, FAR 91.205, and applicable ADs - in that order
• Most small GA aircraft have no MEL, making the KOEL the critical first real filter in the process
• Inoperative equipment that clears all four steps must be deactivated and placarded before flight
• The IFR clock requirement can be satisfied by a wristwatch with a sweep second hand or digital seconds display
• A failed transponder does not ground you everywhere - the restriction applies only in specific airspace defined by FAR 91.215
• Regulations define the legal minimum; pilot judgment determines what’s actually safe