An airplane flying straight and level at 160 KIAS (above its 132 KIAS maneuvering speed) encounters a sharp vertical gust. Why does this create a greater risk of structural damage compared to encountering the same gust at or below Va?
- AAbove Va, stall speed decreases significantly, providing a larger safety margin against structural damage
- BAbove Va, the higher dynamic pressure allows the gust to generate a load factor that can exceed the airplane's limit load factor before the wing stalls
- CAbove Va, induced drag decreases sharply, which reduces structural loading during the gust
- DAbove Va, the wing reaches its critical angle of attack and stalls before the load factor limit is exceeded, protecting the structure
Show answer & explanationAnswer & explanation
Correct answer: B. Above Va, the higher dynamic pressure allows the gust to generate a load factor that can exceed the airplane's limit load factor before the wing stalls
Maneuvering speed is defined as the speed at which the wing will stall before the limit load factor is exceeded during an abrupt maneuver or gust. Above Va, higher dynamic pressure means a gust can generate enough lift (and load factor) to exceed structural limits before the wing reaches critical AOA and stalls, risking structural failure.
Why the other options are wrong
- A. Stall speed does not decrease with airspeed; this option misstates the aerodynamic relationship.
- C. Induced drag changes do not protect the structure from gust loading; this is irrelevant to the risk described.
- D. This describes the protective behavior below Va, not above it — reversed logic.
Maneuvering Speed (Va) and Gust Protection
Va is the speed at which the wing stalls before generating a load factor exceeding structural limits during an abrupt gust or maneuver; above Va, structural damage can occur before a protective stall.
- Below or at Va, stall occurs before structural limit load factor is reached.
- Above Va, dynamic pressure allows lift (and load factor) to exceed limits before stall.
- Va decreases with weight, since a lighter airplane stalls sooner for a given load factor.
Memory trick: Below Va, you stall first and stay safe; above Va, you break first.