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MEL letter of authorization status

Aviation Mechanic General (AMG) practice question 20 of 37 on Regulations, Maintenance Forms, Records, and Publications. ACS element AM.I.I.K12 · difficulty: standard. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONAn operator plans to fly an aircraft with certain equipment inoperative by operating under a minimum equipment list (MEL). According to the handbook's discussion of § 91.213(a)(2), the letter of authorization from the FSDO that permits operation under the MEL is treated as what?

  1. AAn airworthiness directive that must be filed with the aircraft's permanent records
  2. BA supplemental type certificate that must be carried in the aircraft during flight
  3. CA special flight permit that need not be carried on board
Show the answer and explanation

Correct answer: B. A supplemental type certificate that must be carried in the aircraft during flight

  • A — incorrect The letter of authorization is not an airworthiness directive; ADs are issued under part 39 to correct unsafe conditions.
  • B — correct The handbook states that the FSDO letter of authorization for MEL operation constitutes a supplemental type certificate and must be carried in the aircraft during flight.
  • C — incorrect The handbook says the letter must be carried in the aircraft during flight, and it is described as constituting an STC, not a special flight permit.

BACKGROUND

14 CFR part 91 is primarily an operating regulation, but the Aviation Maintenance Technician Handbook–General points out several maintenance-related sections that a technician must know. One is § 91.213, Inoperative Instruments and Equipment. The handbook explains that under paragraph (a)(2), a letter of authorization from the Flight Standards District Office (FSDO) authorizing operation of the aircraft under a minimum equipment list (MEL) constitutes a supplemental type certificate (STC) and must be carried in the aircraft during flight. An MEL allows an aircraft to be operated with specified equipment inoperative, and the handbook elsewhere notes that a part once removed as damaged cannot simply be reinstalled regardless of its deferability under the MEL.

STUDY TIP

Link the MEL letter of authorization to two ideas: it has the status of an STC, and it must be on board during flight.

KEY POINTS

  • § 91.213 governs inoperative instruments and equipment.
  • The FSDO letter of authorization for MEL operation constitutes an STC.
  • That letter must be carried in the aircraft during flight.

SOURCES

  • FAA-H-8083-30B ch02 "14 CFR Part 91--General Operating and Flight Rules" (Section 91.213 discussion)
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SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.