Airframe Mechanic Certification Airframe Inspection Procedures 4 — Questions and Answers
Question 1: During a hard landing inspection, which structural area requires priority examination on a conventional gear aircraft?
- Wing leading edges and stall strips
- Firewall, engine mounts, and main gear attachment structure (Correct answer)
- Pitot-static ports and angle-of-attack vanes
- Rudder hinge brackets and tailcone skin
Correct answer: Firewall, engine mounts, and main gear attachment structure
Hard landing loads transfer through the main gear into the attachment structure and firewall area, making these areas the priority for overload damage.
Question 2: What is the maximum allowable depth of a scratch on a structural aluminum tube before repair or replacement is required, according to AC 43.13-1B?
- 10% of wall thickness (Correct answer)
- 50% of wall thickness
- 5% of outside diameter
- Any scratch requires immediate replacement
Correct answer: 10% of wall thickness
AC 43.13-1B limits scratches in structural tubing to 10% of wall thickness; deeper scratches require repair or replacement.
Question 3: Which regulatory reference would a mechanic consult to determine if a specific airframe repair is classified as major or minor?
- 14 CFR Part 43, Appendix A (Correct answer)
- 14 CFR Part 65.81
- AC 43.13-2B
- 14 CFR Part 91.409
Correct answer: 14 CFR Part 43, Appendix A
14 CFR Part 43, Appendix A defines major alterations, major repairs, and minor repairs and alterations for airframes and other aircraft systems.
Question 4: When performing a visual inspection of flight control cables, which condition would most likely require replacement of the cable?
- Slight discoloration of the cable outer strands
- Three broken wires in one lay of a 7×19 cable (Correct answer)
- Cable tension 5% below the specified value
- Presence of cable lubricant on the outer strands
Correct answer: Three broken wires in one lay of a 7×19 cable
AC 43.13-1B states that cables with three or more broken wires in one lay length are typically cause for rejection and replacement.
Question 5: A mechanic finds corrosion on a steel tubular fuselage truss. After removing the corrosion, the affected tube wall thickness is reduced by 15%. What should be done?
- Refinish and return to service since corrosion is removed
- Apply epoxy primer and monitor at the next inspection
- Consult the manufacturer's structural repair manual; likely replacement or reinforcement is needed (Correct answer)
- Polish the area smooth and re-measure at 25-hour intervals
Correct answer: Consult the manufacturer's structural repair manual; likely replacement or reinforcement is needed
Wall thickness reduction of 15% on a structural tube likely exceeds acceptable limits and requires engineering data or SRM guidance before return to service.
Question 6: What does the term 'airworthy' mean as applied during an airframe inspection?
- The aircraft has a current annual inspection within the past 12 months
- The aircraft conforms to its type design and is in a condition for safe operation (Correct answer)
- The aircraft has no write-ups in the maintenance log
- The aircraft has passed all required AD compliance items only
Correct answer: The aircraft conforms to its type design and is in a condition for safe operation
Airworthy means the aircraft conforms to its approved type design and is in a condition for safe operation, per 14 CFR Part 3.
Question 7: During inspection of a fabric-covered aircraft, the punch test is used to evaluate fabric condition. What does a passing result indicate?
- The fabric is free of all mildew and UV damage
- The fabric meets the minimum tensile strength specified in FAA-approved data (Correct answer)
- The fabric color has not faded beyond limits
- The fabric has been properly doped within the last two years
Correct answer: The fabric meets the minimum tensile strength specified in FAA-approved data
The punch test estimates residual tensile strength of aircraft fabric; a result meeting or exceeding the FAA-approved minimum confirms airworthy fabric condition.
