FAR 91.205 Required Equipment: What Must Be Working to Fly

You are completing your preflight and notice the attitude indicator is sluggish and unreliable. You are planned for an IFR departure in 30 minutes. Can you legally go? The answer depends entirely on your understanding of FAR 91.205 — and the companion rule most pilots forget.

14 CFR 91.205 is the FAA regulation that determines whether your aircraft’s instruments and equipment are legally sufficient for the operation you intend to fly. It is not a list you memorize once for a written exam and then forget. It is a three-tier operational dispatch standard — covering day VFR, night VFR, and IFR — that every pilot must understand as a preflight airworthiness decision tool. The regulation applies to powered civil aircraft with a standard U.S. airworthiness certificate, and FAA training guidance, including AC 91-67A, treats 91.205 as the baseline legal standard for equipment-related go/no-go decisions.

The safety stakes are real. Equipment failures can degrade situational awareness, compromise navigation reliability, and eliminate electrical redundancy — all of which matter whether you are flying VFR on a clear morning or shooting an approach to minimums. Understanding FAR 91.205 required equipment rules means understanding whether your aircraft is legally and operationally ready to fly.

FAR 91.205 Day VFR Required Equipment: The ATOMATOFLAMES Baseline

The foundation of 91.205 is the day VFR required instruments and equipment list found in 91.205(b). This is the minimum equipment tier — every night VFR and IFR requirement builds on top of it. Most flight training programs teach this tier using the ATOMATOFLAMES mnemonic, which is a widely recognized memory aid. But a mnemonic is not the regulation. It is a teaching tool tied to the regulatory text, and the exact requirements depend on your specific aircraft’s configuration.

Here is what the ATOMATOFLAMES mnemonic covers, mapped to the FAR 91.205 required equipment list:

• A — Airspeed indicator
• T — Tachometer (for each engine)
• O — Oil pressure gauge (for each engine using a pressure system)
• M — Magnetic direction indicator (compass)
• A — Altimeter
• T — Temperature gauge (for each liquid-cooled engine)
• O — Oil temperature gauge (for each air-cooled engine)
• F — Fuel quantity indicator for each tank
• L — Landing gear position indicator (if retractable gear)
• A — Anti-collision lights (for aircraft certificated after March 11, 1996)
• M — Manifold pressure gauge (for each altitude engine and each engine with a controllable-pitch propeller)
• E — ELT (governed separately under 14 CFR 91.207, but referenced in equipment discussions)
• S — Safety belts (and shoulder harnesses, if required) for each occupant

Day VFR is commonly taught as approximately 11 required items, but that number is not fixed. It shifts based on aircraft configuration, engine type, and installed systems. A fixed-gear Cessna 172 does not need a landing gear position indicator. A turbine-powered aircraft has different temperature gauge requirements than a piston single. The mnemonic gets you close — the regulation and your aircraft’s documentation get you compliant.

Conditional Requirements Most Pilots Miss

Several items in 91.205(b) are conditional, and this is where rote mnemonic recitation fails. The manifold pressure gauge is required for each altitude engine and each engine with a controllable-pitch propeller — not all aircraft need one. The temperature gauge requirement differs between liquid-cooled and air-cooled engines. The landing gear position indicator applies only to retractable-gear aircraft.

Pilots must verify their specific aircraft’s type certificate data sheet and equipment list — not rely solely on a mnemonic. This is a critical preflight airworthiness step that separates regulatory compliance from rote memorization.

Night VFR Required Equipment Under 91.205: Adding FLAPS

Night VFR operations under 91.205(c) require everything from the day VFR list plus additional items commonly taught with the FLAPS night VFR mnemonic. The three-tier structure is cumulative: night VFR is not a standalone list — it is day VFR plus FLAPS.

The additional 91.205 night VFR required equipment items are:

• F — Fuses: one spare set, or three spare fuses of each kind required (or circuit breakers)
• L — Landing light (required only if the aircraft is operated for hire)
• A — Anti-collision lights
• P — Position lights (navigation lights)
• S — Source of electrical energy adequate for all installed electrical and radio equipment

This adds approximately 4 to 5 items to the day VFR baseline, depending on how the source-of-electrical-energy requirement is counted relative to the mnemonic. One detail that surprises many students: the landing light is required at night only when operating for hire under this section. If you are flying a personal night VFR flight, FAR 91.205 does not mandate a landing light — though operational good judgment strongly favors having one. The source-of-electrical-energy requirement is also significant: it ensures your aircraft can power every installed electrical device, not just the ones you plan to use.

IFR Required Equipment Under FAR 91.205: The GRABCARD Layer

The IFR tier under 91.205(d) is the most complex dispatch decision a pilot faces under this regulation. All day VFR and night VFR items are required, plus IFR-specific instruments and equipment commonly taught with the GRABCARD IFR equipment mnemonic. Note that the exact letters and groupings vary slightly across training sources — what matters is that every item in 91.205(d) is accounted for:

• G — Generator or alternator of adequate capacity
• R — Rate-of-turn indicator (gyroscopic rate-of-turn indicator or equivalent)
• A — Attitude indicator
• B — Ball (slip-skid indicator)
• C — Clock displaying hours, minutes, and seconds (or digital equivalent)
• A — Adjustable (sensitive) altimeter adjustable for barometric pressure
• R — Radios: two-way radio communication and navigation equipment suitable for the route to be flown
• D — Directional gyro or equivalent (e.g., HSI, EHSI)

This adds approximately 8 items on top of day and night VFR requirements, creating a materially more complex dispatch decision. The cumulative structure means IFR compliance under FAR 91.205 requires day VFR + night VFR + GRABCARD — the full stack.

The generator or alternator requirement is frequently overlooked because it is not an instrument — it is a systems-level requirement ensuring adequate electrical capacity for all required equipment for IFR flight. Without it, every electrically powered instrument on your panel is on borrowed time. The sensitive altimeter requirement is distinct from the basic altimeter required for VFR; it must be adjustable for barometric pressure, which directly affects IFR altitude compliance. And the navigation equipment must be suitable for the route to be flown — a requirement that increasingly connects to GPS/RNAV database currency in current training.

Glass Cockpit Considerations Under 91.205

In aircraft with integrated avionics suites like the Garmin G1000, a single primary flight display failure can affect multiple 91.205 required instruments simultaneously — airspeed, attitude, altimeter, and heading information may all disappear from one screen. This can instantly render the aircraft non-compliant for IFR, or even for VFR in some configurations. Pilots operating glass-cockpit aircraft must understand which backup instruments — standby attitude indicators, magnetic compasses, standby airspeed indicators — satisfy FAR 91.205 when primary displays fail. This is an increasingly critical training focus as the fleet modernizes.

Installed vs. Operative: The Distinction That Grounds Flights

Here is the misconception that creates the most risk: pilots assume that if a required instrument is physically installed in the panel, the aircraft is legal to fly. It is not. FAR 91.205 requires that each item be in operable condition for the intended operation. Installed but inoperative does not equal available for dispatch.

Consider the scenario from the opening of this article. An attitude indicator that is installed but stuck, flagged, or giving unreliable readings is not legally operative for an IFR departure. The instrument is physically present. It may even power up and display something. But it does not meet the airworthiness requirements of 91.205(d), and you cannot legally depart IFR without proper action under 14 CFR 91.213 or an approved minimum equipment list.

This three-way distinction — required, installed, and operative — is tested on checkrides and has direct safety consequences. An inoperative instrument does not care whether you noticed it. The regulation requires that you verify operability during every preflight, for every operation.

When Equipment Breaks: The FAR 91.205 and 91.213 Workflow

Two rules work together here. 91.205 tells you what must be there and working. 91.213 tells you what to do when something is not working. They are companion rules — not separate topics — and understanding the 91.205 vs 91.213 inoperative instruments workflow is essential for every pilot.

When you discover an inoperative item, follow this decision process:

1. Is the item required by 91.205 for the planned operation (day VFR, night VFR, or IFR)?
2. Is it required by the aircraft’s type certificate data sheet, equipment list, any other FAR, or any applicable Airworthiness Directive?
3. Does the aircraft have an approved MEL (minimum equipment list)? If yes, follow the MEL procedures.
4. If no approved MEL exists, follow the 91.213(d) deferral process: determine whether the item is required by any of the sources listed above. If the item is not required by any of those authorities, it may be deferred — but it must be placarded as inoperative, and if it is a flight-safety item, it must be deactivated or removed by appropriately rated personnel before flight. Pilots should carefully evaluate all four conditions in 91.213(d) rather than independently assuming an item may be deferred.

FAA Advisory Circular AC 91-67A is the active guidance document for this process under Part 91 operations — a reference almost never cited in pilot-facing content, but one that provides the FAA’s accepted framework for minimum-equipment decision-making. For a deeper dive into MEL procedures and inoperative-equipment workflows, see CTS’s Minimum Equipment List (MEL) Training.

The bottom line: if a required item under FAR 91.213 inoperative equipment rules cannot be properly deferred, the aircraft does not fly for that operation. Period.

Common Misconceptions About FAR 91.205

• Misconception: “If the equipment is installed, it’s okay to fly.”
  Reality: The item must be operative for the intended operation. Installed but inoperative is not legally compliant without proper action under 91.213.
• Misconception: “91.205 is only about IFR.”
  Reality: FAR 91.205 covers three tiers — day VFR, night VFR, and IFR. The day VFR tier applies to every powered civil flight under a standard airworthiness certificate.
• Misconception: “The ATOMATOFLAMES mnemonic IS the regulation.”
  Reality: Mnemonics are teaching aids. The actual legal requirements are in the regulatory text and vary by aircraft configuration, engine type, and installed systems.
• Misconception: “A broken non-critical piece can always be ignored.”
  Reality: If the item is required by 91.205 for the planned flight, it cannot be ignored without following the 91.213 compliance process.
• Misconception: “IFR equipment is VFR equipment plus radios.”
  Reality: IFR adds approximately 8 specific items, including a gyroscopic rate-of-turn indicator, sensitive altimeter, attitude indicator, and a generator or alternator of adequate capacity — far more than communications gear alone.

Frequently Asked Questions About FAR 91.205

What equipment is required for day VFR flight under FAR 91.205?
Day VFR required instruments under 91.205(b) include an airspeed indicator, altimeter, magnetic direction indicator, tachometer, oil pressure and temperature gauges, fuel quantity indicators, anti-collision lights, and safety belts — commonly taught as approximately 11 items via the ATOMATOFLAMES mnemonic. The exact count varies by aircraft configuration, as items like the landing gear position indicator apply only to retractable-gear aircraft and the manifold pressure gauge applies only to altitude engines and controllable-pitch propeller installations.

What does FAR 91.205 require for IFR flight?
Required equipment for IFR flight under FAR 91.205 includes all day VFR and night VFR items, plus approximately 8 additional instruments and systems: generator or alternator of adequate capacity, gyroscopic rate-of-turn indicator, attitude indicator, slip-skid indicator, clock with seconds, sensitive altimeter, two-way radios and navigation equipment suitable for the route, and a directional gyro. See the GRABCARD section above for full details.

Can I fly with inoperative equipment under 91.205?
Not without following the proper process. If the inoperative item is required by 91.205 for your planned operation, you must address it under 14 CFR 91.213 — either through an approved MEL or through the 91.213(d) deferral process. You cannot depart with a required item inoperative unless it is legally deferred.

What is the difference between 91.205 and 91.213?
FAR 91.205 defines what equipment must be installed and operative for each type of operation. 91.213 defines the process for dealing with inoperative equipment — including whether the item can be deferred, must be placarded, or must be repaired before flight. They are companion rules that work together as a single workflow.

What does ATOMATOFLAMES stand for, and is it the actual regulation?
ATOMATOFLAMES stands for Airspeed indicator, Tachometer, Oil pressure gauge, Magnetic direction indicator, Altimeter, Temperature gauge, Oil temperature gauge, Fuel quantity indicator, Landing gear position indicator, Anti-collision lights, Manifold pressure gauge, ELT (per 91.207), and Safety belts. It is a mnemonic — a memory aid — not the regulation itself. The actual requirements are in 14 CFR 91.205(b) and depend on your aircraft’s specific configuration.

Making FAR 91.205 Part of Your Preflight Workflow

Knowing 91.205 for a checkride is the starting point. Using it as an operational tool every time you fly is the standard. During every preflight, verify that each required instrument and piece of equipment is not only present but operative for the flight you intend to conduct. If something is broken, run the 91.213 workflow before making a dispatch decision — not after you are already taxiing.

Recurrent training should reinforce the connection between FAR 91.205 and 91.213, especially as avionics evolve and glass-cockpit failures create new airworthiness questions. Instrument-rated pilots should periodically review IFR-specific requirements under 91.205, particularly as GPS/RNAV database currency becomes a routine part of the preflight go/no-go decision. The goal is to transform rote knowledge into confident, applied airworthiness decision-making.

Structured, scenario-based training programs are the most effective way to build that confidence. Rather than memorizing mnemonics in isolation, pilots benefit from equipment-failure exercises that force real dispatch decisions under realistic conditions. Strengthen your regulatory knowledge and go/no-go decision-making with CTS’s IS-BAO/Part 91 Training and Minimum Equipment List (MEL) Training — programs designed to build the operational confidence that goes beyond memorizing mnemonics.