Editor’s note (October 2026): This article predates the FAA’s current guidance. Under 14 CFR 91.213(d), inoperative equipment must be removed, or deactivated and placarded “Inoperative,” before flight. FAA Advisory Circular 91-67A (2023) adds that deactivation is not preventive maintenance: whatever the method, a person authorized under 14 CFR 43.7 must make the maintenance record entry. Involve a mechanic before you fly. For the current process, see our guide to required equipment and flying with inoperative equipment.
Can you fly your airplane with that missing or inoperative equipment?
Problem: Can you fly home anyway or do you need to hire an A&P technician? Here’s how to know for sure … well, four ways, actually.
Solution: The Four-Step Test, described in FAR 91.213, provides the procedure that pilots should use to determine if it is both safe and legal to fly while one or more items are missing or inoperative. The test helps the pilot make the proper decision to fly or not to fly with a broken Outside Air Temperature Gauge, or a burned out position light, or a radio missing from the panel. Every pilot should know how to apply the test.
Step 1: FARs. Is the inoperative or missing equipment required by the VFR Day Type Certificate of the airplane? If it is required, then the airplane should not be flown until that item is repaired or replaced. What exactly is a VFR Day Type Certificate? It is the original equipment required when the aircraft was manufactured, but they can be hard to find. For starters, you can use the list of required equipment of FAR 91.205(b). That is a list of 16 items that must be present and working properly for VFR Daytime flight. If the item in question is not on that list, you’re ready to go … to Step 2.
Step 2: POH. Is the inoperative or missing equipment required by the aircraft’s equipment list? Each manufacturer provides a list (usually found in the POH) of all instruments and equipment that could be on the aircraft. Some are listed as “optional” others are “standard” but the important ones are listed as “required.” If an item is missing or inoperative that is on the “required” equipment list, then that airplane is grounded. If it is not listed as “required,” you’re all set … for Step 3.
Step 3: ADs. Is the inoperative or missing equipment required by any Airworthiness Directives (AD)? An AD is a “recall” that could require certain aircraft to have particular equipment. You might need to consult an A&P technician to be sure about what ADs apply to your aircraft. If an AD requires equipment that is missing or inoperative, then that aircraft is grounded. If not, you’re off and running … to Step 4.
Step 4: Other. Is the inoperative or missing equipment required by any other regulation pertaining to your flight? This is the “catch-all” part of the regulation. Night flight, high altitude flight, instrument flight, and flight into congested airspace all require additional equipment. You can fly VFR without an Attitude Gyro for instance, but it is required for an IFR flight. If you pass all four steps of the test, then you can safely and legally go fly.
But wait! There is one more thing you must do before takeoff. If the item in question is missing, you must make sure that the item is not included on the aircraft’s weight and balance form. If the item is inoperative, it must be deactivated and placarded “INOP” (or removed) before takeoff. Deactivation is maintenance, so have a mechanic do it and record it.
BOTTOM LINE: Using the Four-Step test will make it possible to safely and legally fly home in most situations. So learn to apply the test - and be ready to explain it if you ever get ramp checked!