Aircraft Systems and Structures
Core concepts
Candidates need functional knowledge of airframe structures (primary and secondary structure, load paths, fatigue-critical areas, corrosion-prone zones) and the major systems: hydraulic, pneumatic, electrical, fuel, flight controls, landing gear, ice and rain protection, and pressurization. Understand the difference between fail-safe and safe-life design philosophies and what each means for inspection strategy. Know how zonal inspections and structural sampling programs work, and why damage tolerance drives inspection intervals. For systems, know normal operation, indications, and common failure modes well enough to interpret a discrepancy report.
Traps in questions
Questions often blur structural categories: a fastener hole in a primary load path is not equivalent to a fairing attachment. Another trap is assuming a system indication directly equals a component failure; indications can reflect sensor, wiring, or power issues. Watch for confusion between redundancy (multiple channels) and independence (no common failure path). Also be careful with composite structures: damage assessment differs from metallic structures, and allowable damage limits are specific to the approved data.
Worked example / rule of thumb
Rule of thumb: Find the load path before deciding the disposition. Worked example: a dent is found on a wing skin. The correct approach is to identify the structural zone and applicable allowable damage limits in the approved data, then decide whether it is within limits, requires blend-out, or requires engineering assessment. A dent in a non-structural fairing is handled differently from one in a primary load-carrying skin. Never apply a generic cosmetic criterion to primary structure.