Section 9, Lesson 1
In Progress

Inoperative Equipment

Inoperative Equipment

How do we proceed when equipment is broken? This is an important topic for pilots, because they must apply their knowledge of it all the time. Equipment will break, and often you can fly with the broken equipment. But, you need to know how to do so legally and safely.


Lesson Notes

Sometimes, non-essential equipment will be inoperative. Unfortunately, with the FAA you technically cannot legally fly an airplane with required broken equipment unless there is a legally approved process for such an operation. Essentially, your airworthiness certificate is valid if and only if all required equipment is operational. However, the FAA has established protocols for flying with inoperative equipment. This is generally a four-step process. Ask yourself if the equipment is:

  • Part of the day or night (if applicable) requirements (§91.205)
  • Required by Airworthiness Directive (AD)
  • Required by the aircraft’s Kinds of Operation Equipment List (KOEL)
  • Required by Type Certificate Data Sheets (TCDS).

If it is not required by any of those four, it is non-essential and is not legally required for flight. It is the PIC responsibility, however, to know the flight can still be operated safely, with the equipment broken. If a flight will proceed with legally inoperative equipment, that equipment must be deactivated (i.e. pull the circuit breaker) and placarded (labeled) as inoperative. This is so that you or another pilot will not mistakenly use the broken equipment. The necessity of placards is highlighted in the airlines, where the job is so repetitive that pilots would easily forget what equipment is inoperative. Without placards, pilots would constantly operate switches for broken equipment.

Additional Resources


Flashcard Questions

What four steps are required to determine if one can legally fly with inoperative equipment? (without an MEL)

Why would we want to disable/remove inoperative equipment?

What is the TCDS?

What are ADs?

Know how to access (and ideally have a copy of) your aircraft’s ADs, TCDS and, if you have one, KOEL.

You are the proud owner of a small airplane. You find out that the manufacturer has issued an AD to reinforce the tail structure. Compliance is required effective immediately. How long do you have until you cannot fly before complying with the AD?

You discover upon preflight that your airplane has an inoperative taxi light. It is daylight, and you’ll only be out for about 30 minutes, so you decide to take the airplane and have the local mechanic fix it after you land. Is this legal? More importantly, is there any safety issue associated with this? How does the safety situation change if this is a club airplane that will be flown by other pilots later in the day?

Know how to access (and ideally have a copy of) your aircraft’s ADs, TCDS and, if you have one, KOEL.