What is the difference between FAR 91.213 and FAR 91.205?

FAR 91.205 lists the equipment required for specific operations - day VFR, night VFR, IFR. FAR 91.213 is the decision framework pilots use when equipment is inoperative, and it incorporates 91.205 as one of its four questions.

Can a flight instructor authorize flight with inoperative equipment?

No. A flight instructor's verbal assurance does not satisfy the regulatory requirements of FAR 91.213. Inoperative equipment must either pass the four-question deferral process (and be legally placarded), be removed by a certificated mechanic, or be repaired before flight.

What does "placarded inoperative" mean in practice?

A label - typically reading "INOPERATIVE" - must be affixed to or near the failed instrument or control in the cockpit where the crew can see it. The maintenance record should also reflect the deferred item and the basis for the deferral.

Do I need to check both the POH and the FARs when evaluating inoperative equipment?

Yes - both are required. The KOEL in the POH and FAR 91.205 are separate, equally binding sources. An item not mentioned in the FARs may still be required by the aircraft's type certificate, and vice versa.

What are the consequences of flying with equipment that should have grounded the aircraft?

Flying with inoperative required equipment that doesn't meet FAR 91.213's deferral criteria is a federal aviation regulation violation and can result in certificate action or civil penalties - regardless of whether an incident or accident occurs.

FAR Ninety-One Point Two Thirteen, the Inoperative Equipment Decision Flow, and the Four Questions That Tell You If the Airplane Is Legal to Fly Before You Start the Engine

FAR 91.213 governs inoperative instruments and equipment under Part 91 general aviation operations. It exists because the FAA recognized that not every broken component should ground an aircraft - and that pilots need a structured, documented process to make that determination legally. Knowing this framework is one of the most practically useful skills a pilot can develop, and one of the most common checkride scenarios.

What Does FAR 91.213 Actually Cover?

FAR 91.213 applies to Part 91 operations, which covers the vast majority of general aviation flying - a Cessna 172 at a local flight school, a rented Piper Cherokee, a Diamond DA20. If you’re operating under Part 121 (airlines) or Part 135 (charter), different and generally stricter rules apply.

The regulation offers two paths, and which path you take depends on one key question: does the aircraft have a Minimum Equipment List (MEL)?

Does Your Aircraft Have an MEL?

An MEL is a document specific to that aircraft, approved by the FAA, identifying which items can be inoperative under which conditions while still permitting flight. It’s a formal, legal carve-out for specific equipment failures - when other systems or defined procedures compensate for the deficiency.

Large commercial aircraft almost always have MELs. Most light general aviation training aircraft do not.

If your aircraft has an MEL, the process is straightforward: find the broken item in the MEL and follow the instructions exactly. The MEL is the authority. If it says no-go, it’s a no-go. If it permits flight under specific conditions - daytime VFR only, a defined crew procedure - you follow those conditions precisely.

Without an MEL, FAR 91.213 provides a four-question decision flow. All four questions must be answered “no” before you can legally fly with an inoperative item. A single “yes” grounds the aircraft until maintenance addresses the problem.

Question 1: Is the Item Required by the Type Certificate?

Every certificated aircraft was approved with a specific list of required equipment. Part of that list appears in the Kinds of Operations Equipment List (KOEL), found in the Pilot’s Operating Handbook (POH) or Aircraft Flight Manual.

The KOEL identifies what equipment is required for day VFR, night VFR, IFR, and other operation types. The POH carries regulatory weight - it isn’t just a performance reference document. If the KOEL lists an item as required for your planned operation and that item is broken, you cannot legally fly that mission.

A common mistake is checking the FARs and stopping there. The KOEL is equally binding, and it’s a separate source. You need to check both.

Question 2: Is the Item Required by FAR 91.205?

FAR 91.205 is the required equipment regulation - the one behind the memory aids from the written test. TOMATO FLAMES covers day VFR requirements; FLAPS covers the additional equipment required for night VFR.

If the broken item appears on the required list for your specific operation, you cannot depart. A broken altimeter is required for all VFR operations. A broken position light is required for night VFR.

The critical nuance: the question isn’t whether an item appears on the list in general - it’s whether it’s required for this specific operation, today. A broken landing light on a day VFR local flight is a different analysis than a broken altimeter on any flight. You’re answering for the actual intended flight, not an abstract category.

Question 3: Does an Airworthiness Directive Require the Equipment?

Airworthiness Directives (ADs) are FAA-mandated maintenance actions issued when a safety issue is identified in a specific aircraft or component. Some ADs require certain equipment to be functional before flight.

If there’s an applicable AD on the broken item requiring it to be operational, the aircraft is grounded - full stop.

As a student pilot, you may not be researching ADs yourself - that’s primarily a maintenance function. But understanding that ADs exist and can affect flyability is part of why you review maintenance records during preflight, and part of why you ask questions when something is squawked but not corrected.

Question 4: Does the Broken Item Create a Hazard?

This question belongs to the pilot-in-command. Even if the broken item clears the first three questions, the PIC must make a judgment about whether the inoperative equipment creates a safety hazard for this specific flight.

A clock with a dead battery on a clear VFR afternoon probably poses no hazard. A gyroscopic attitude indicator giving intermittent false readings is a potential hazard even on a VFR flight, should conditions deteriorate. The regulation gives pilots discretion here - and places the responsibility squarely on them.

What Happens After an Item Passes the Four-Question Test?

Clearing all four questions doesn’t mean you ignore the broken item and fly. FAR 91.213 requires that inoperative equipment be handled in one of two ways:

Removed from the aircraft by a certificated mechanic, with the maintenance record updated, or
Deactivated and placarded as inoperative, with the placard visible in the cockpit to the crew.

The placard requirement ensures that any pilot who flies the aircraft - a ferry pilot, a student in an unfamiliar airplane - knows what isn’t working. The squawk in the logbook isn’t just a note; it’s the beginning of a paper trail that must lead either to a repair or a documented, legal deferral decision.

Is a Broken Fuel Gauge Legal to Fly With?

Consider this scenario: a right fuel gauge that reads empty regardless of actual tank level. Maintenance hasn’t been scheduled. An instructor says, “We just do a visual check - it’s fine.”

Run the four questions.

Question 1: Check the KOEL in the specific POH. For most Cessna 172 variants, fuel quantity gauges are listed as required equipment. The model year and variant matter - check yours.

Question 2: FAR 91.205 explicitly requires fuel gauge indicators showing the quantity of fuel in each tank as a day VFR requirement. A gauge that is broken and unreadable fails here.

Question 3: Check maintenance records for any applicable ADs covering the failed component.

Question 4: A fuel gauge that reads empty on a full tank creates a real hazard - particularly for a pilot who doesn’t know the quirk of the airplane and might trust the gauge in a moment of distraction.

The answer is almost certainly no - the aircraft is not legal to fly as-is. A verbal assurance from an instructor that “we just visually check it” may be a practical workaround, but it does not satisfy the regulation.

How Checkride Examiners Test This Knowledge

Checkride examiners don’t ask students to recite required equipment lists from memory. They present a scenario: here’s a squawk, tell me if we’re legal, walk me through your decision. That’s what the Airman Certification Standards (ACS) assess - not memorization, but a demonstrated decision-making process.

The complete decision flow, clean:

Does the aircraft have an MEL? If yes, consult it and follow it exactly.
If no MEL, apply the four questions:
- Is the item required by the type certificate or KOEL?
- Is the item required by FAR 91.205 for this specific operation?
- Does an airworthiness directive require the item to be operational?
- Does the broken item create a hazard to the aircraft or occupants?
If all four answers are “no,” the item may be deferred - but it must still be deactivated, placarded, and logged (or removed by a mechanic).
If any answer is “yes,” the aircraft needs maintenance before flight.

Key Takeaways

FAR 91.213 is designed to give pilots structured flexibility, not to ground every aircraft with a minor squawk - but that flexibility requires doing the actual analysis.
If the aircraft has an MEL, it is the controlling authority. Follow it exactly.
Without an MEL, all four questions must be answered “no”: type certificate/KOEL, FAR 91.205, ADs, and PIC hazard judgment.
Passing the four questions isn’t the end - the item must be deactivated, placarded, and documented, or removed by a certificated mechanic.
A verbal “that’s always been like that” from a front desk or instructor is not a legal determination. Know the framework so you can make the call yourself.