The Pilot in Command is responsible for determining airworthiness of the aircraft by checking compliance of required inspections and visually inspecting the airplane prior to flight. Most of the time everything is normal and works properly but occasionally you may find equipment that is visibly damaged or malfunctioning. Is the airplane airworthy?
FAR 91.213 – Inoperative Instruments and Equipment
This regulation clearly states what the PIC must do to ensure airworthiness with inoperative equipment. Much of the regulation talks about a Minimum Equipment List (MEL) but that is a topic for another article. We are concerned with paragraph (d)(2) which lists four documents that must be checked to determine airworthiness.
1. Type Certificate
2. Aircraft Equipment List
3. FARs (91.205)
4. Airworthiness Directives (ADs)
Let’s look at each of these documents individually:
Every airplane (non-experimental) is certified with a type certificate which describes the approved components, limitations and certification basis referencing specific regulations. This document will describe the C172 is designed to fly with a Lycoming IO-360 engine, has a wing, rudder, elevator, etc. If something is broken and you need to look at this document then you probably need to speak with a mechanic for additional guidance.
Aircraft Equipment List
Check the aircraft’s Equipment List or Kinds of Operations List. Different manufacturers publish this list in different ways. Cessna publishes an Equipment List in Section 6 of the POH including all required, standard and optional equipment. We can see in the sample below the item number, description, reference drawing (for mx manuals), weight and arm for each light. The –S in the item number denotes our landing light is standard equipment but not required for flight by Cessna. Required items are denoted –R and must be operative.
This regulation lists specific equipment required to be operational depending on flight conditions. Your instructor likely taught you TOMATOFLAMES for Day VFR equipment, FLAPS for Night VFR and GRABCARD for IFR. If you can’t remember each item just remember 91.205 so you know where to find the information you need. If your affected equipment is on this list, time to call a mechanic.
Airworthiness Directives (ADs)
Lastly, check to make sure there are no applicable ADs for the inoperative equipment. Sometimes an AD will list specific requirements for your type of airplane and operation. For example, an AD may require a landing light to be operational if the taxi light is out of service. These situations are very system specific to the airplane and must be checked.
Now What?
If you determine the inoperative equipment is not required FAR 91.213 goes on to say the equipment must be deactivated and placarded “inoperative.” If deactivation involves maintenance then it must be accomplished by a mechanic in accordance with Part 43. Any installed equipment removed from the airplane must be reflected in an updated weight & balance sheet. For most items, such as a landing light, the pilot can simply pull and collar the circuit breaker and apply an INOP label to the switch. Non-electrical items are a little trickier. If the glass on your VSI is cracked, the crack itself disables the instrument so the pilot just applies the placard.
Lastly, the PIC must determine if the inoperative equipment constitutes a hazard to flight. Depending on your experience level and personal minimums, you may not feel comfortable flying with a particular item inoperative even if you may legally do so. As PIC you are the final authority and responsible for the operation of the aircraft.
