Why Va Usually Is Too Fast

Youve probably seen something like the chart above before in your studies. Its known variously as a V-G diagram, gust diagram or simply an airplanes flight envelope. From it, we can determine the g-loading the represented airplane will experience when accelerated beyond 1G at various airspeeds. For example, the airplane depicted may suffer structural damage at 200 mph if it encounters conditions leading to a 4G loading. Those conditions can include pilot input, turbulence or some combination.

Editorial Staff

Thursday, February 26, 2015 at 12:00 AM ET

Verified

Key Takeaways:

An airplane's response to G-loading (structural damage vs. stall) is dependent on its airspeed, emphasizing the importance of slowing down in turbulence to prevent structural damage.
The published turbulence penetration speed (VA) is typically valid only at an aircraft's maximum takeoff weight; VA decreases proportionally with lower aircraft weight (e.g., due to fuel burn).
Pilots should calculate a weight-adjusted VA using a specific formula to determine the safe turbulence penetration speed for current flight conditions and always fly slightly below it.

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Youve probably seen something like the chart below before in your studies. Its known variously as a V-G diagram, gust diagram or simply an airplanes flight envelope. From it, we can determine the g-loading the represented airplane will experience when accelerated beyond 1G at various airspeeds. For example, the airplane depicted may suffer structural damage at 200 mph if it encounters conditions leading to a 4G loading. Those conditions can include pilot input, turbulence or some combination.