What type of aircraft must be inspected with an inspection program authorized under Federal Aviation Regulation 91, Subpart E?

• A. small airplanes
• B. large airplanes and turbine-powered multi-engine airplanes operated under Part 91
• C. rotorcraft
• D. general aviation airplanes

Answer: (C)

Rotorcraft have a requirement for an FAA-approved inspection program under FAR 91 Subpart E because their maintenance needs are particularly complex and safety-critical, especially components like the rotor system and drive train. The Subpart E framework allows a formal, documented inspection program with defined intervals and tasks tailored to rotorcraft, ensuring consistent airworthiness management beyond standard schedules. Other categories listed—small airplanes, large airplanes and turbine-powered multi-engine airplanes operated under Part 91, and general aviation airplanes—follow the more common maintenance and inspection rules (such as annual or 100-hour inspections) rather than an FAA-approved Subpart E inspection program.