The rules about flying with inoperative equipment are
complicated, and have changed a lot. Here’s the latest.
BY MIKE BUSCH
IS YOUR AIRPLANE SQUAWK-FREE? I know mine isn’t. At any given
point in time, you’ll find a yellow Post-it note on the instrument
panel of my 1979 Cessna T310R listing all known squawks. Any time
I notice a discrepancy, I jot it down so I won’t forget to deal with it
next time I’m wrenching on the airplane. At the moment, there are
six items on my Post-it note list.
Six known discrepancies is a lot. It reflects the fact that I haven’t
had the time to work on my airplane for a while. All these items
need to be fixed, but none of them strike me as being particularly
serious. From time to time, however, my Post-it note has contained
more serious items such as “left vacuum pump inop” or “right alternator inop.”
How serious does a problem need to be before it becomes an airworthiness issue and renders the aircraft “too broken to fly”?
As pilot in command, you have a regulatory responsibility to
make an airworthiness determination before every flight, and to reevaluate that determination throughout every flight:
§ 91. 7 CIVIL AIRCRAFT AIRWORTHINESS.
(a) No person may operate a civil aircraft unless it is in an airworthy condition.
(b) The pilot in command of a civil aircraft is responsible for determining whether
that aircraft is in condition for safe flight. The pilot in command shall
discontinue the flight when unairworthy mechanical, electrical, or structural
But how are you supposed to do this? Is it legal to fly with a failed
vacuum pump? A burned out nav light? A failed GPS or comm radio?
An inoperative stall warning sensor? A flaky fuel flow gauge? A
sticky airspeed indicator? A bad mic jack in the No. 4 passenger seat?
How do you determine which squawks render the aircraft unflyable
and which don’t?
One way is to ask your mechanic. A&Ps, and particularly IAs,
have gone through extensive training in how to make such
airworthiness determinations. Often, however, discrepancies are
discovered outside of regular business hours—on weekends and
holidays—when consulting a mechanic may be difficult or
impossible. Also, most pilots are understandably reluctant to bother
their mechanics with anything short of discrepancies that are
The other way is to consult the FARs.
The rule concerning flight with inoperative
equipment—§ 91.213—is long, complex, and
not particularly easy to parse unless you
have a law degree—but it’s something that
every pilot and aircraft owner needs to
understand. Let’s start by looking at the
rule’s overall structure:
§ 91.213 INOPERATIVE INSTRUMENTS AND EQUIPMENT.
(a) Except as provided in paragraph (d) of this section,
no person may take off an aircraft with inoperative
instruments or equipment installed unless the
following conditions are met:
( 1) An approved Minimum Equipment List exists for
( 2) The aircraft has within it a letter of
authorization, issued by the FAA Flight
Standards district office having jurisdiction
over the area in which the operator is located,
authorizing operation of the aircraft under the
Minimum Equipment List. …
(…a bunch of stuff about MELs appears here…)
(d) Except for operations conducted in accordance with
paragraph (a) … of this section, a person may take
off an aircraft in operations conducted under this
part with inoperative instruments and equipment
without an approved Minimum Equipment
( 1) The flight operation is conducted in a—
(i) Rotorcraft, non-turbine-powered airplane,
glider, lighter-than-air aircraft, powered
parachute, or weight-shift-control aircraft,
for which a master Minimum Equipment
List has not been developed; or
(ii) Small rotorcraft, non-turbine-powered
small airplane, glider, or lighter-than-
air aircraft for which a master Minimum
Equipment List has been developed; and