Which publication contains standards for protrusion of bolts, studs, and screws through self locking nuts?

• A. AC 43.13-1B
• B. FAR Part 23
• C. AC 91-1
• D. AC 27

Answer: (A)

Protrusion limits for fasteners through self-locking nuts are part of maintenance guidance for hands-on aircraft work. The FAA’s advisory circular that covers acceptable methods, techniques, and practices—including how bolts, studs, and screws should protrude through self-locking nuts—is AC 43.13-1B. This publication is the go-to source for such installation details to ensure proper nut seating, safe interference with adjacent parts, and reliable locking.

The other items are design or operation references rather than maintenance procedures: FAR Part 23 relates to airworthiness standards for the design of small airplanes, AC 91-1 covers general flight operations, and AC 27 pertains to rotorcraft certification.