Airframe Mechanic Certification Safety Procedures & Regulatory Compliance 4 — Questions and Answers
Question 1: What is the minimum color specification for safety wire used on aircraft engine hardware?
- Any stainless steel wire regardless of diameter
- Monel or stainless steel wire of the diameter specified in the applicable maintenance manual (Correct answer)
- Galvanized steel wire, which is standard for non-critical applications
- Copper wire, which is the industry standard for most fasteners
Correct answer: Monel or stainless steel wire of the diameter specified in the applicable maintenance manual
Safety wire must be made of Monel or stainless steel of the diameter specified in the applicable maintenance manual or standard practice for the application.
Question 2: Under OSHA regulations applicable to aircraft maintenance facilities, what is the permissible exposure limit (PEL) for a substance that would require a mechanic to wear a respirator?
- Any detectable concentration of hazardous vapors
- Concentrations exceeding the PEL established in 29 CFR 1910.1000 (Correct answer)
- Only concentrations that are immediately dangerous to life or health (IDLH)
- Concentrations exceeding 50% of the lower explosive limit (LEL)
Correct answer: Concentrations exceeding the PEL established in 29 CFR 1910.1000
OSHA's permissible exposure limits in 29 CFR 1910.1000 establish the maximum allowable concentrations of airborne contaminants, and respiratory protection is required when those limits are exceeded.
Question 3: A repair station certificate under 14 CFR Part 145 requires which of the following to be maintained at all times?
- An FAA Safety Attribute Inspection every 6 months
- Housing, equipment, and personnel appropriate for the ratings held (Correct answer)
- A minimum of 10 certificated mechanics on staff
- Direct FAA oversight of all maintenance performed
Correct answer: Housing, equipment, and personnel appropriate for the ratings held
A Part 145 repair station must continuously maintain appropriate housing, equipment, materials, and qualified personnel necessary for the ratings shown on its certificate.
Question 4: When performing a ground run-up to check engine performance after maintenance, what minimum safety precaution is required for personnel near the aircraft?
- Personnel must remain inside the hangar until engine shutdown
- A fire guard must be posted and personnel must stay clear of prop and exhaust danger zones (Correct answer)
- Two mechanics must be in the cockpit at all times during run-up
- Ground support equipment must be removed to at least 500 feet
Correct answer: A fire guard must be posted and personnel must stay clear of prop and exhaust danger zones
During engine ground run-up, a fire guard must be posted and all personnel must remain clear of propeller arc, exhaust, and intake danger zones.
Question 5: Which regulation requires aircraft operators to comply with Airworthiness Directives?
- 14 CFR 39.7 (Correct answer)
- 14 CFR 43.13
- 14 CFR 91.403
- 14 CFR 65.81
Correct answer: 14 CFR 39.7
14 CFR 39.7 states that no person may operate a product to which an Airworthiness Directive applies except in accordance with the requirements of that AD.
Question 6: What is the significance of a 'stop-drill' applied to a crack in an aircraft aluminum structure?
- It permanently repairs the crack and restores full structural integrity
- It temporarily arrests crack propagation by eliminating the stress concentration at the crack tip (Correct answer)
- It marks the crack location for future inspection reference only
- It is required before applying a chemical conversion coating to the area
Correct answer: It temporarily arrests crack propagation by eliminating the stress concentration at the crack tip
A stop-drill temporarily arrests crack propagation by drilling a small hole at the tip of the crack, which eliminates the sharp stress concentration that drives continued cracking.
Question 7: When an aircraft component is found to be un-airworthy during an inspection, what is the correct disposition per 14 CFR Part 43?
- The component must be destroyed to prevent inadvertent use
- The component must be tagged unserviceable and either repaired, altered, or scrapped in accordance with approved data (Correct answer)
- The owner must be notified and given 30 days to arrange repair
- The FAA must be immediately notified and an incident report filed
Correct answer: The component must be tagged unserviceable and either repaired, altered, or scrapped in accordance with approved data
Unairworthy components must be tagged unserviceable and then either repaired using approved data, altered, or removed from service and scrapped.
Airframe Mechanic Certification Safety Procedures & Regulatory Compliance 4
What is the minimum color specification for safety wire used on aircraft engine hardware?