Aircraft Structures Flashcards
7 cards from real Airframe Mechanic Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Aircraft Structures flashcards as text
What is the term for the ratio of the ultimate load that causes structural failure to the design limit load an aircraft is expected to experience in service?
Answer: Safety factor
The safety factor (typically 1.5 for FAR Part 25 transport aircraft) is the ratio of ultimate load to limit load, providing a margin for uncertainties.
Which inspection method is most appropriate for detecting subsurface fatigue cracks in aluminum wing skins without removing the skin?
Answer: Eddy current inspection
Eddy current inspection can detect subsurface cracks in non-ferrous metals like aluminum without requiring surface preparation or skin removal.
A doubter (doubler) plate installed over a cracked fuselage skin repair serves primarily to:
Answer: Restore original strength and stop-drill the crack
A doubler plate bridges the cracked area, restores load-carrying capacity, and distributes stress away from the crack tip after stop-drilling.
What structural phenomenon occurs when thin aircraft skin panels buckle under shear loading but still carry additional load through diagonal tension?
Answer: Wagner field or diagonal tension
Wagner field (diagonal tension) describes post-buckling behavior where shear-buckled skin carries additional load through diagonal tensile stress fields.
When determining the minimum edge distance for a rivet installed in an aircraft skin repair, what is the generally accepted minimum distance from rivet centerline to the sheet edge?
Answer: 2 times the rivet diameter
FAA AC 43.13-1B specifies a minimum edge distance of 2 times the rivet diameter to prevent shear-out failure of the sheet material.
In a damage-tolerant aircraft structure, what is the purpose of fracture mechanics-based inspection intervals?
Answer: To ensure cracks are detected and repaired before reaching critical size
Fracture mechanics sets inspection intervals so that any crack growing from the assumed initial flaw size will be found and repaired before it reaches the critical size that causes failure.
Which condition must be verified before performing a flush rivet repair on a pressurized fuselage skin to ensure it meets original design intent?
Answer: The repair restores original skin thickness, strength, and pressure-tightness
A pressurized fuselage repair must restore original material thickness and strength while also maintaining airtight integrity against the pressure differential in flight.