Under FAA regulations, IFR flight requires every instrument needed for daytime VFR flight, every instrument needed for nighttime VFR flight, plus nine additional items specific to instrument operations. The full list comes from 14 CFR 91.205, and pilots commonly use mnemonics to remember the IFR-specific additions. Beyond the instruments themselves, certain inspections and certifications must be current before you can legally depart IFR.
The VFR Baseline You Already Need
IFR equipment requirements build on top of what’s already required for VFR day and VFR night flight. Before adding anything IFR-specific, your aircraft needs the standard VFR day instruments: airspeed indicator, altimeter, magnetic compass, tachometer for each engine, oil pressure gauge, oil temperature gauge (air-cooled engines) or coolant temperature gauge (liquid-cooled engines), manifold pressure gauge for altitude engines, fuel quantity gauges for each tank, landing gear position indicator (if retractable), and an emergency locator transmitter.
For night VFR, which IFR also requires, you add position lights, an anticollision light system (red or white), an adequate electrical power source for all installed electrical and radio equipment, and spare fuses accessible to the pilot in flight.
The IFR-Specific Equipment List
On top of that VFR foundation, 14 CFR 91.205(d) requires these additional items for instrument flight:
- Two-way radio communications and navigation equipment suitable for the route to be flown
- Gyroscopic rate-of-turn indicator (turn coordinator or turn-and-slip indicator), unless the aircraft has a third attitude instrument system capable of full 360-degree pitch and roll display
- Slip-skid indicator (the ball in the inclinometer)
- Sensitive altimeter adjustable for barometric pressure
- Clock displaying hours, minutes, and seconds with a sweep-second pointer or digital presentation
- Generator or alternator of adequate capacity
- Gyroscopic pitch and bank indicator (attitude indicator or artificial horizon)
- Gyroscopic direction indicator (heading indicator or equivalent)
Many pilots memorize the IFR additions with the mnemonic GRABCARD: Generator, Radios (two-way comm and nav), Attitude indicator, Ball (slip-skid indicator), Clock, Altimeter (sensitive, adjustable), Rate-of-turn indicator, and Directional gyro.
What “Suitable for the Route” Actually Means
The regulation’s most flexible requirement is also its most important: navigation equipment “suitable for the route to be flown.” The FAA does not specify a single type of nav equipment for all IFR flights. Instead, your equipment must match the specific routes, airways, and approaches in your flight plan.
If you’re flying Victor airways defined by VOR stations, you need a working VOR receiver. If your route includes GPS-based T-routes or Q-routes, you need an IFR-approved GPS. If your destination’s only instrument approach is an ILS, you need a localizer and glideslope receiver. The same logic applies to your alternate airport: you cannot file to an alternate unless your aircraft has the navigation equipment to fly an approach there.
For GPS to qualify as IFR navigation, the unit must meet specific certification standards. Older panel-mount GPS units certified to TSO-C129 are approved for certain IFR operations, including RNAV routes and GPS approaches down to LNAV minimums, but they carry a limitation: the aircraft must also have another form of navigation equipment appropriate to the flight. WAAS-capable GPS units (certified to TSO-C145 or TSO-C146) do not carry that limitation and can serve as the sole source of navigation. WAAS is not mandatory for IFR flight, but it opens up approaches with lower minimums, including LPV approaches that rival ILS precision.
ADS-B Out and Transponder Requirements
While not listed in the 91.205 equipment list itself, ADS-B Out is effectively required for most IFR flying. Since January 2020, any airspace that previously required a Mode C transponder now requires ADS-B Out. That covers all of Class A, Class B, and Class C airspace, Class E airspace at and above 10,000 feet MSL (except below 2,500 feet AGL), and the Mode C veil extending 30 nautical miles around major airports.
Below 18,000 feet within the US, you can use either a 1090ES transponder-based system or a UAT (Universal Access Transceiver) system. At Flight Level 180 and above, only a 1090ES system is acceptable. The equipment must meet Version 2 performance standards. If you’re filing IFR into any of this airspace without ADS-B Out, your flight plan will be a problem.
Required Inspections and Checks
Having the right equipment installed isn’t enough. Several items require current inspections before you can legally fly IFR.
Your altimeter, static pressure system, and automatic altitude reporting system (the encoding altimeter that feeds your transponder) must have been tested and inspected within the preceding 24 calendar months. This pitot-static check ensures your altitude readouts are accurate, which is critical when ATC is separating you from other traffic by altitude. The inspection must find the systems in compliance with the standards in Part 43, Appendices E and F.
If you’re using VOR navigation, the VOR receiver must have been operationally checked within the preceding 30 days. You can do this check yourself using a VOR test facility (VOT), a designated ground checkpoint, or a designated airborne checkpoint. The tolerances differ by method: ground checks allow a maximum error of plus or minus 4 degrees, while airborne checks allow plus or minus 6 degrees. Each VOR check must be logged with the date, location, bearing error, and your signature.
High-Altitude and Specialty Route Equipment
Certain routes and altitude blocks demand additional navigation capability. RNAV 2 is the standard navigation specification for T-routes and Q-routes, requiring aircraft to maintain a total system error of no more than 2 nautical miles for 95 percent of flight time. RNAV 1, with a tighter 1-nautical-mile accuracy requirement, typically applies to departure procedures and arrival routes (SIDs and STARs).
RNP approaches (titled RNAV (GPS) on US charts) offer several tiers of minimums depending on your equipment. With a basic IFR GPS, you can fly LNAV minimums. A WAAS-capable GPS unlocks LPV minimums, which provide vertical guidance similar to an ILS. The most demanding procedures, labeled RNP AR, require specific aircraft certification and FAA authorization beyond standard IFR equipment.
What Happens If Equipment Fails in Flight
If your two-way radio fails during an IFR flight, specific rules under 14 CFR 91.185 dictate what to do next. In VMC conditions, you continue VFR and land as soon as practicable. In IMC, you fly the last assigned route (or the route you were told to expect, or your filed route as a last resort) at the highest of your last assigned altitude, the minimum IFR altitude, or the altitude ATC told you to expect. You then proceed to your destination and begin your approach as close as possible to your expected arrival time.
For navigation equipment failures, the situation depends on what’s left working. If your GPS fails but you have VOR capability and the route can be flown with VOR, you continue. If you lose the ability to navigate the route entirely, you’re dealing with an emergency. The key principle is that the regulation requires equipment “suitable for the route,” so carrying backup navigation capability, while not always legally required, provides a significant safety margin in instrument conditions.