Airframe Mechanic Airframe Inspection Procedures Questions and Answers — Questions and Answers
Question 1: A mechanic is inspecting a main wing spar made of aluminum alloy for suspected subsurface cracks originating from a fastener hole. Which NDT method is most effective for this specific task?
- Magnetic Particle Inspection
- Dye Penetrant Inspection
- Eddy Current Inspection (Correct answer)
- Visual Tap Test
Correct answer: Eddy Current Inspection
Eddy current inspection is highly effective at detecting surface and near-surface flaws in conductive materials, like aluminum. It is particularly well-suited for finding cracks around fastener holes. Magnetic particle is for ferrous metals, dye penetrant only finds surface-breaking cracks, and tap testing is for composite delamination.
Question 2: During a detailed fuselage inspection, a mechanic notes fine, worm-like filaments of corrosion forming under the paint near a lap joint. This observation is most characteristic of which type of corrosion?
- Pitting Corrosion
- Filiform Corrosion (Correct answer)
- Intergranular Corrosion
- Fretting Corrosion
Correct answer: Filiform Corrosion
Filiform corrosion is characterized by its distinctive thread-like or worm-like appearance as it creeps under a coating, such as paint. [1, 21] It is common on aluminum and steel surfaces, especially in high-humidity environments. [1, 10, 21]
Question 3: Which of the following statements correctly describes a key relationship between a 100-hour inspection and an annual inspection?
- The scope of a 100-hour inspection can be used to satisfy the requirements of an annual inspection.
- The scope and detail of an annual inspection can be used to satisfy the requirements of a 100-hour inspection. (Correct answer)
- An A&P mechanic with Inspection Authorization (IA) is required to perform and sign off both inspection types.
- A 100-hour inspection is required for all private aircraft, while an annual is only for aircraft used for hire.
Correct answer: The scope and detail of an annual inspection can be used to satisfy the requirements of a 100-hour inspection.
According to 14 CFR 91.409, an annual inspection is required for most aircraft every 12 calendar months. A 100-hour inspection is required for aircraft operated for hire. [13, 16] The scope of an annual inspection is identical to or more comprehensive than a 100-hour inspection, so it can be used to meet the 100-hour requirement, but the reverse is not true. An A&P can perform a 100-hour inspection, but an A&P with Inspection Authorization (IA) is required for an annual. [9, 16]
Question 4: An aircraft is subject to a mandatory, legally enforceable rule issued by the FAA that requires a specific inspection of the horizontal stabilizer attachment fittings due to a known unsafe condition. This type of rule is known as a(n):
- Service Bulletin (SB)
- Maintenance Manual Revision
- Airworthiness Directive (AD) (Correct answer)
- Type Certificate Data Sheet (TCDS) update
Correct answer: Airworthiness Directive (AD)
An Airworthiness Directive (AD) is a legally enforceable regulation issued by the FAA to correct an unsafe condition found in a product (aircraft, engine, propeller, or appliance). [8, 17, 20] Compliance is mandatory. [20] Service Bulletins are recommendations from the manufacturer and are not legally mandatory unless referenced in an AD.
Question 5: When an inspector performs a 'tap test' on a bonded honeycomb composite panel, what is the primary type of defect they are trying to detect?
- Surface porosity in the face sheet
- Improper electrical bonding of the panel
- Incorrect honeycomb core cell size
- Delamination or disbond between the face sheet and core (Correct answer)
Correct answer: Delamination or disbond between the face sheet and core
Tap testing is a common non-destructive inspection method for composite structures. A sharp, clear 'ring' indicates a good bond, while a dull 'thud' sound indicates a void, delamination, or disbond between the skin and the honeycomb core. [18, 24, 30]
Question 6: When visually inspecting a primary structural member of an all-metal aircraft, such as a wing root fitting, which of the following findings would be considered the MOST critical?
- Light surface oxidation
- A small, smooth-edged dent
- A crack originating from a rivet hole (Correct answer)
- Chipped or flaking paint
Correct answer: A crack originating from a rivet hole
While all discrepancies must be evaluated, a crack in a primary structural member is the most critical because it represents a failure of the material that can propagate under load, potentially leading to catastrophic failure of the structure. [3, 19] Cracks often start at stress concentration points like rivet holes.
Airframe Mechanic Airframe Inspection Procedures Questions and Answers
A mechanic is inspecting a main wing spar made of aluminum alloy for suspected subsurface cracks originating from a fastener hole.
Which NDT method is most effective for this specific task?