100+ Free NZ CAA PPL Aircraft Technical Practice Questions

Explanation: In a true monocoque fuselage structure, the outer skin provides the primary structural strength and absorbs flight and ground loads without relying on internal framing. Thin-walled monocoque structures offer light weight but are vulnerable to denting or buckling under localized stress. Most modern light aircraft use a semi-monocoque design combining skin, stringers, and bulkheads.

Explanation: Aluminium alloys (such as 2024-T3) offer an excellent strength-to-weight ratio, high ductility, and straightforward manufacturing characteristics, making them ideal for light aircraft structures. However, aluminium requires protective coatings or alclad layers to prevent corrosion. Aircraft aluminium is susceptible to metal fatigue and environmental degradation over time.

Explanation: In flight, upward lift bends the wing structure upward, placing the upper skin and upper spar flange into compression while the lower skin is subjected to tension. On the ground, weight causes the wing to sag, reversing these stresses so the upper skin experiences tension. Structural designers account for both in-flight and ground loading conditions.

Explanation: Differential ailerons are designed so that the up-moving aileron deflects higher into the airstream than the down-moving aileron lowers. The larger upward deflection creates additional parasite drag on the inside wing of the turn, opposing adverse yaw caused by induced drag on the rising wing. This design assists the pilot in achieving coordinated banked turns with less required rudder input.

Explanation: Semi-monocoque construction combines a thin aluminum or composite skin with internal longitudinal members (longerons and stringers) and vertical formers/bulkheads. This internal framework stiffens the skin, preventing localized buckling under high bending or twisting loads while maintaining structural efficiency. Most modern metal aircraft are constructed using semi-monocoque principles.

Explanation: Intergranular corrosion attacks along the microscopic grain boundaries of heat-treated aluminium alloys. It often progresses internally under the metal surface, causing severe structural degradation that may remain undetected until exfoliation or structural failure occurs. Regular inspections and proper corrosion-inhibiting treatments (like zinc chromate primers) are essential in marine environments like New Zealand.

Explanation: Wooden airframe structures (typically high-grade Sitka spruce bonded with synthetic or casein glues) are vulnerable to moisture ingress, which can cause glue line failure, timber swelling, and fungal decay (dry rot). Routine maintenance requires inspecting drainage holes, checking fabric seals, and testing glue joints for delamination. Moisture content must be controlled to maintain structural integrity.

Explanation: During a 2.0g maneuver in flight, upward aerodynamic lift forces bend the wing assembly upward relative to the heavy fuselage. This places the upper spar cap (flange) into intense compression and the lower spar cap into high tension. On the ground while taxiing, gravity acts downward on the wings and fuel tanks, placing the top spar cap in mild tension and the bottom spar cap in compression.

Explanation: An anti-servo tab on a stabilator moves in the SAME direction as the stabilator's trailing edge deflection. This creates an aerodynamic force that opposes pilot control column displacement, providing essential artificial stick feel (proportional control force) to prevent the pilot from inadvertently over-stressing the airframe. It also increases the effective camber and pitching authority of the stabilator.

Explanation: Frise ailerons feature an offset hinge line. When the aileron moves upward to lower the wing, its nose (leading edge) protrudes beneath the lower wing surface into the airflow. This exposed nose creates parasite drag on the inside wing of the turn, helping offset the induced drag produced by the opposite down-going aileron, thereby counteracting adverse yaw.