SkyDrill

When a service bulletin becomes mandatory

Aviation Mechanic Powerplant (AMP) practice question 8 of 9 on Engine Inspection. ACS element AM.III.C.K4 · difficulty: standard. Want to answer it in a timed quiz? Use the Aviation Mechanic Powerplant (AMP) practice mode.

Question bank updated 2026-09-22

QUESTIONAn engine manufacturer issues a service bulletin covering a design improvement. When does compliance with that service bulletin become required?

  1. AWhen an airworthiness directive refers to it.
  2. BWhen the bulletin is issued by the engine maker.
  3. CNever; bulletins are always advisory information.
Show the answer and explanation

Correct answer: A. When an airworthiness directive refers to it.

  • A — correct Service bulletins are not required unless they are referred to in an airworthiness directive note or unless compliance is required as part of the authorized inspection program.
  • B — incorrect Issuance alone does not make a bulletin binding; the handbook states bulletins are good information that should be strongly considered, but are not required on their own.
  • C — incorrect Saying a bulletin can never be binding is too broad, because an airworthiness directive or the authorized inspection program can make compliance mandatory.

BACKGROUND

Manufacturing defects, changes in service, and design improvements occur throughout the life of a product, and the original equipment manufacturer (OEM) frequently distributes that information to the operator of the aircraft in a service bulletin (SB). Service bulletins carry useful information and should be strongly considered by the owner for implementation, but they are not required unless they are referred to in an airworthiness directive (AD) note or unless compliance is required as part of the authorized inspection program; the handbook refers the reader to 14 CFR part 39, § 39.27 on this point. At the receiving inspection that begins an overhaul, the engine's service bulletins, airworthiness directives, and type certificate compliance should all be checked, along with a review of the engine's log books.

STUDY TIP

Keep the hierarchy straight: an AD is a rule, while a service bulletin is manufacturer information that becomes binding only when an AD or an approved inspection program pulls it in.

KEY POINTS

  • Service bulletins are manufacturer information, not rules by themselves
  • An AD reference, or an authorized inspection program, makes a bulletin mandatory
  • SB, AD, and type certificate compliance are all reviewed at the receiving inspection

SOURCES

  • amp-powerplant/ch10.txt "General Overhaul Procedures"
  • 14 CFR 39.27 (as cited in the handbook text)
Practice the Aviation Mechanic Powerplant (AMP) test →Timed 100-question exam, by ACS area, or review your misses. Free.
MORE ON ENGINE INSPECTION

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-32B Aviation Maintenance Technician Handbook – Powerplant, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.