What equipment is required for IFR flight under 14 CFR 91.205?

Under 14 CFR 91.205(d), aircraft operated under IFR must be equipped with the following: a gyroscopic rate-of-turn indicator, slip-skid indicator, sensitive altimeter adjustable for barometric pressure, a clock with hours, minutes, and seconds, attitude indicator, heading indicator, and a VOR or approved navigation receiver suitable for the route. Additionally, the aircraft must have two-way radio communication and navigation equipment appropriate for the ground facilities to be used. Many pilots use the memory aid 'GRABCARD' to recall these items. This list is in addition to the VFR day and night equipment requirements found in 91.205(b) and (c).

What is the difference between VFR and IFR equipment requirements under 91.205?

14 CFR 91.205 is structured in layers: 91.205(b) covers the minimum equipment for VFR day flight, 91.205(c) adds items required for VFR night flight such as position lights and an anti-collision light system, and 91.205(d) specifies the additional instruments and avionics required for IFR operations. The IFR category uniquely mandates gyroscopic instruments, a sensitive altimeter, navigation receivers, and two-way radio communication that are not required for VFR flight. Understanding this layered structure is a key concept tested on the FAA Instrument Rating Airplane Knowledge Test.

Why does IFR flight require a gyroscopic attitude indicator and heading indicator?

In IMC, pilots lose the natural visual horizon references they rely on in VFR conditions, making the attitude indicator and heading indicator essential for maintaining controlled flight and accurate navigation. The FAA's Instrument Flying Handbook emphasizes that without these gyroscopic instruments, a pilot cannot reliably detect or correct bank and pitch attitude, which can rapidly lead to spatial disorientation. These instruments provide the primary attitude and directional information needed to safely execute instrument procedures, holds, and approaches. 14 CFR 91.205(d) mandates them because no other standard cockpit instrument can substitute for their function in IMC.

IFR Equipment Requirements for Aircraft (91.205)

Before you file an IFR flight plan and launch into the clouds, federal regulations require your aircraft to be equipped with a very specific set of instruments and systems. The primary rule governing this is 14 CFR 91.205, which lays out minimum equipment requirements for powered civil aircraft operating under visual and instrument flight rules. For IFR flight in particular, 91.205(d) lists what must be installed and operational — and knowing this list is not just a test requirement, it is a genuine safety foundation. An instrument rating is only as useful as the aircraft that backs it up.

This article walks you through every required item for IFR operations, explains why each one is on the list, and highlights the distinctions that frequently trip up students on the FAA Instrument Rating knowledge test.

Starting Point: VFR Day Equipment (The Baseline)

The IFR equipment list builds on top of the VFR day and VFR night requirements. Before adding IFR-specific gear, your aircraft must already carry everything required for VFR day flight under 91.205(b). The classic mnemonic for VFR day equipment is A TOMATO FLAMES, covering items such as the altimeter, tachometer, oil pressure gauge, manifold pressure gauge (if applicable), airspeed indicator, temperature gauge, oil temperature gauge, fuel gauges, landing gear position indicator, anti-collision lights, magnetic compass, ELT, and seat belts. Then VFR night adds items from FLAPS (fuses, landing light if for hire, anti-collision lights, position lights, and source of electrical energy). The IFR list then adds its own layer on top of all of this.

IFR-Specific Equipment: 91.205(d)

Under 91.205(d), for IFR flight you must have all equipment required for VFR flight plus the following instruments and systems. These are the items specifically listed for flight under instrument flight rules in controlled or uncontrolled airspace:

Generator or alternator of adequate capacity — A reliable source of electrical power is essential because most IFR instruments and avionics are electrically powered. Without a functioning alternator or generator, your electrical bus cannot sustain the load of radios, transponder, and flight instruments for an extended IFR flight.
Gyroscopic rate-of-turn indicator — 91.205(d)(4) requires a gyroscopic rate-of-turn indicator, except that a turn coordinator with an integral slip-skid indicator (inclinometer) may be substituted for it. It is the instrument the pilot uses to execute timed turns and maintain coordination when the attitude indicator fails.
Slip/skid indicator — Separately required under 91.205(d)(5), this is the ball portion of the turn coordinator or turn-and-slip indicator. It tells the pilot whether the aircraft is in coordinated flight. In most modern aircraft it is built into the turn coordinator, but the regulation lists it as its own required item distinct from the rate-of-turn indicator.
Sensitive altimeter adjustable for barometric pressure — A standard altimeter with a Kollsman window (or equivalent) that allows the pilot to set the local altimeter setting. Altimeter accuracy is critical in IFR because you navigate by altitude, and terrain/traffic separation depends on flying assigned altitudes precisely.
Clock with a sweep-second pointer or digital equivalent — Timing is fundamental to IFR. Timed approaches, holding patterns (one-minute legs), missed approach procedures, and fuel management all depend on having a reliable clock that reads seconds, not just minutes. A digital display showing elapsed seconds satisfies this requirement.
Attitude indicator (gyroscopic) — The primary pitch and bank reference during flight in instrument meteorological conditions (IMC). Without a functioning attitude indicator, maintaining aircraft control in IMC becomes extraordinarily difficult. It must be gyroscopically driven (vacuum or electrically powered).
Heading indicator (gyroscopic directional gyro) — The magnetic compass is unreliable during turning and acceleration/deceleration errors, making it unsuitable as the primary heading reference in IMC. The heading indicator provides a stable, precession-free heading readout during normal flight. It must be synchronized with the compass periodically.
DME or suitable RNAV equipment — Required specifically when operating at or above FL240 (flight level 24,000 feet MSL) if VOR navigation is used. At high altitudes in the domestic airspace structure, distance measuring equipment or area navigation capability is required because VOR radials spread out with distance and high-altitude route navigation demands more precise position awareness. Below FL240, DME is not universally required just for IFR flight, though it may be required by specific approaches or routes.
VOR receiver or suitable RNAV system — Required when operating on Victor airways or jet routes that are defined by VOR radials, or when conducting a VOR instrument approach. The regulation requires the ability to navigate by the airways and approaches in the IFR system. Modern GPS RNAV systems may substitute for VOR navigation on many routes and approaches, subject to the applicable TSO standards and database currency requirements.
Two-way radio communications equipment — IFR operations require constant communication capability with ATC. You must be able to receive and transmit on the frequencies assigned for your route, including departure, en route, approach, and tower frequencies. A single radio that can transmit and receive satisfies the two-way requirement, though most IFR pilots carry two for redundancy.

Why Each Item Is on the List

It helps to understand the IFR equipment list not as an arbitrary checklist but as a reflection of what a pilot actually needs to maintain aircraft control and situational awareness when the outside world disappears into cloud. The attitude indicator and heading indicator are the twin pillars of primary instrument flight — they replace the natural visual cues of the horizon and landmarks that a VFR pilot relies on. The turn coordinator and ball provide a backup attitude reference and coordination check. The sensitive altimeter keeps you on assigned altitudes to the nearest 20–30 feet. The clock converts your groundspeed and procedures into actionable, time-bounded maneuvers. The radios and navigation receivers keep you connected to the ATC system and allow you to follow assigned routes and fly published approaches. The alternator powers all of the above.

Inoperative Equipment and the MEL

What happens when one of these items fails before or during flight? Under 14 CFR 91.213, an aircraft may be operated with inoperative instruments or equipment only if those items are not required by 91.205, not required by the aircraft's type certificate, not listed as required on an approved Minimum Equipment List (MEL), and the item is deactivated and placarded. Note that the type certificate is a distinct document from the airworthiness certificate. If a required IFR instrument is inoperative, you cannot legally fly IFR — period. This is why instrument pilots always conduct a thorough preflight check of every instrument on the 91.205(d) list, not just a glance at the panel.

Key Numbers and Rules

DME requirement begins at FL240 when navigating using VOR-based airways.
The clock must display seconds (sweep-second hand or digital seconds readout).
The altimeter must be adjustable for barometric pressure — a non-adjustable altimeter does not meet the requirement.
All gyroscopic instruments (attitude indicator, heading indicator, rate-of-turn indicator) must be functioning and properly calibrated for the flight.
Two-way radio is required — this means both transmit and receive capability on applicable frequencies.
Below FL240, you may navigate IFR with a certified GPS RNAV system in lieu of VOR on many routes, but must comply with applicable NOTAMs regarding GPS RAIM availability.

Memory Aid

The classic mnemonic for IFR equipment is GRABCARD. Each letter stands for a required item:

G — Generator or alternator
R — Rate-of-turn indicator (turn coordinator or turn-and-slip)
A — Attitude indicator
B — Ball (slip/skid indicator)
C — Clock (with seconds capability)
A — Altimeter (sensitive, adjustable)
R — Radio (two-way communications)
D — DME (at or above FL240 if using VOR navigation)

Think of GRABCARD as grabbing your card to get cleared into the clouds — it is the ticket you need before ATC lets you go IFR. Remember that this mnemonic covers the additional IFR items on top of the VFR requirements; do not forget the underlying A TOMATO FLAMES baseline.

Common Test Traps

DME altitude threshold confusion: Students sometimes think DME is required for all IFR flight. It is only specifically required at or above FL240 when using VOR navigation. Below that altitude, it may be required by a specific approach or route, but not by 91.205(d) alone.
Forgetting the clock must show seconds: A watch with only hour and minute hands does not meet the requirement. The FAA specifically requires a seconds-capable display because timed holds and approaches are measured in seconds.
Confusing the altimeter requirement: The rule calls for a sensitive altimeter adjustable for barometric pressure. A basic, non-adjustable altimeter fails the requirement. The Kollsman window (or equivalent) must be present and functional.
Treating GRABCARD as the complete list: GRABCARD captures the IFR-specific additions, but the full legal requirement includes everything from VFR day (A TOMATO FLAMES) and VFR night (FLAPS) plus GRABCARD. The FAA knowledge test may ask about a complete equipment list and expect you to combine all three layers.
Assuming a GPS alone satisfies all navigation requirements: While GPS RNAV systems can substitute for VOR on many IFR routes and approaches, specific regulatory criteria must be met, including TSO authorization, current databases, and RAIM availability. GPS does not automatically replace every VOR or DME requirement in every situation.