What does ATOMATOFLAMES stand for?

It's the memory aid for day VFR required equipment under FAR 91.205: Airspeed indicator, Tachometer, Oil pressure gauge, Manifold pressure gauge, Altimeter, Temperature gauge, Oil temperature gauge, Fuel gauge, Landing gear position indicator, Anti-collision lights, Magnetic direction indicator, ELT, and Safety belts.

What extra equipment is required for night VFR?

Everything on the day list plus FLAPS: Fuses (spares), Landing light (only if for hire), Anti-collision lights, Position lights, and an adequate Source of electrical power.

Do I always need a landing light at night?

Legally, only if the flight is for hire. A private pilot flying at night isn't strictly required to have one - though flying without a landing light after dark is a personal-minimums decision most pilots wouldn't make.

What regulation covers flying with an inoperative instrument?

FAR 91.213. If there's no MEL, you check whether the item is required by the type certificate, 91.205, an airworthiness directive, or any other regulation. If none require it, it can be placarded inoperative and the flight may proceed.

Can I fly in the daytime if my anti-collision light is broken?

If your airplane was certificated after March 11, 1996, no - it's required even in daytime. If it's an older airframe, you can fly by day with the light placarded inoperative, provided it's repaired as soon as practicable, but it's required again at night.

FAR Ninety-One Two Oh Five, the Instrument Checklist Behind the Word ATOMATOFLAMES, and Why the Placard on Your Panel Isn't the Whole Story on What Has to Work Before You Fly

Federal Aviation Regulation 91.205 lists the minimum instruments and equipment that must be installed and working before you can legally fly under visual flight rules. Most pilots learn it through two memory aids - ATOMATOFLAMES for day VFR and FLAPS for the additional night requirements - but the mnemonics only tell you what equipment exists, not when it’s required or what to do when something breaks. To fly safely and legally, you also need 91.213, the regulation that governs inoperative instruments and equipment.

What equipment is required for day VFR flight?

For daytime flight under visual flight rules, the required equipment is captured by the word ATOMATOFLAMES. Each letter stands for one item that must be installed and operational:

A - Airspeed indicator
T - Tachometer, one for each engine
O - Oil pressure gauge, one for each engine using a pressure system
M - Manifold pressure gauge, for each altitude engine (constant-speed or turbocharged powerplants)
A - Altimeter
T - Temperature gauge, for each liquid-cooled engine
O - Oil temperature gauge, for each air-cooled engine
F - Fuel gauge, showing the quantity in each tank
L - Landing gear position indicator, if the aircraft has retractable gear
A - Anti-collision light system (a red or white flashing beacon or strobes on newer aircraft)
M - Magnetic direction indicator (the wet “whiskey” compass)
E - Emergency locator transmitter (ELT), where required
S - Safety belts, plus shoulder harnesses on newer airplanes

That’s the full daytime VFR list. Learn it cold - but don’t stop there.

Does the anti-collision light have to work in daytime?

This is the wrinkle the mnemonic can’t carry. If your airplane was certificated after March 11, 1996, you need a working anti-collision light system even in the daytime.

If your airframe is older than that cutoff and the anti-collision light is inoperative, you can still fly in the daytime - as long as the light is repaired as soon as practicable.

The letters give you the what. They don’t tell you the when or which airplane. That distinction is exactly what separates a memorized word from real understanding.

What additional equipment does night VFR require?

For night VFR, you keep everything on the daytime ATOMATOFLAMES list and add a second helping, remembered as FLAPS:

F - Fuses: a spare set, three of each kind, or one spare of each kind if the aircraft uses resettable circuit breakers. Most modern airplanes have resettable breakers, so this requirement quietly takes care of itself - but if you fly something with a glass fuse panel, keep those spares aboard.
L - Landing light: legally required only if the flight is for hire. Flying yourself and a friend at night, the regulation doesn’t strictly require it. As a personal-minimums matter, launching into the dark without a landing light is another conversation entirely - but know the legal difference, because an examiner may ask.
A - Anti-collision lights: required at night with no certification-date exception this time.
P - Position lights (navigation lights): red on the left wing, green on the right, white on the tail, from sundown to sunup.
S - Source of electrical power: an adequate alternator or generator to run all the electrical equipment you’ve just added.

ATOMATOFLAMES for the day. Add FLAPS for the night. Together they let you recite the required equipment for a Cessna 172 on a moonlit evening - which is more than many certificated pilots can do.

What do I do when an instrument is inoperative before a flight?

Say you preflight and find the left-main landing gear position light burned out, or the second tachometer in a twin reading zero. The mnemonic tells you the item exists - it doesn’t tell you whether you can fly. For that, 91.205 hands off to 91.213, the regulation on inoperative instruments and equipment.

Treat 91.213 as a decision tree. Walk it in this order:

Is there a Minimum Equipment List (MEL) for this specific airplane? An MEL is a formal document approved for your tail number. Most Part 91 general aviation airplanes don’t have one, but if you do, you follow it, full stop.
Is the inoperative item required by the type certificate - part of what the airplane needed to be certificated in the first place?
Is it required by 91.205 for the kind of flight you’re about to make?
Is it required by an airworthiness directive (AD)?
Is it required by any other regulation for your specific operation?

If the broken item is required by any one of those, you’re done - the airplane doesn’t fly until it’s repaired or properly deferred by a mechanic.

If the item is not required by any of them, you have a path. Either a mechanic removes or deactivates it and placards it INOPERATIVE, or you as the pilot placard it inoperative yourself, determine the airplane is still safe to fly without it, and note it in the maintenance record or however your operation handles it.

Can the same broken instrument be legal on one flight and illegal on another?

Yes - and this scenario makes it concrete. You walk out and the rotating beacon (the old-style anti-collision light) is dead. Your airplane was built in 1975, certificated long before the 1996 cutoff. It’s a bright, clear morning - day VFR.

Walk the tree. No MEL. Is the beacon required by 91.205 for day VFR on an airplane this old? Remember the exception: you can fly in the daytime with it inoperative as long as it’s repaired as soon as practicable. So you placard it inoperative, make the note, and legally fly the pattern this morning.

But the moment the sun starts setting, the answer flips. At night that beacon is required, with no certification-date exception, and the airplane stays on the ground. Same airplane, same broken light, two different legal outcomes - decided entirely by the time of day. The mnemonic never told you the sun was part of the equation.

The same “required for what flight?” logic governs the transponder and static system. Flying VFR outside controlled airspace, a transponder check under 91.413 and a pitot-static check under 91.411 may not even apply. Add controlled airspace or IFR, and equipment that was optional an hour ago becomes mandatory. The airplane didn’t change - the operation did. Always ask: required for what flight?

How to carry this into your preflight

Don’t just memorize ATOMATOFLAMES and FLAPS and call it done - those are the doorway, not the room. When you find something broken on your next preflight, run the real questions: Do I have an MEL? Is it required by the type certificate? Is it on the 91.205 list for this flight, day or night? Is there an AD? Any other regulation?

If the answer to all of those is no, you have options. If the answer to any of them is yes, you have a phone call to make to a mechanic. That process is what turns a memorized word into genuine pilot-in-command judgment - and deciding whether an airplane is airworthy for a given flight on a given morning is one of the most fundamentally pilot things you’ll ever do. Nobody signs it for you. You sign it.

This material comes straight from FAR 91.205 and FAR 91.213, with the plain-language walkthrough in the FAA’s Airplane Flying Handbook. The regulations are free to read on the FAA website.

Key Takeaways

FAR 91.205 sets the minimum required equipment for VFR flight; ATOMATOFLAMES covers day VFR and FLAPS covers the additional night items.
The mnemonics tell you what equipment exists, not when it’s required - airplanes certificated after March 11, 1996 need a working anti-collision light even in daytime; older airframes can defer it and repair as soon as practicable.
When an instrument is inoperative, FAR 91.213 is the decision tree: check for an MEL, then whether the item is required by the type certificate, 91.205, an AD, or any other regulation.
If a broken item isn’t required by any of those, it can be placarded INOPERATIVE and the flight may proceed; if it is required by even one, the airplane is grounded until fixed or deferred.
Legality depends on the flight, not just the airplane - the same broken beacon can be legal by day and illegal at night.