PLT120: Turbulent Air Penetration Speed
What code PLT120 covers, why the FAA tests it, and how to study Turbulent Air Penetration Speed before your checkride.
Recall aircraft limitations - turbulent air penetration
What this means for your checkride
In turbulence you slow to the airplane's turbulent air penetration speed, near maneuvering speed. At or below that speed the wing stalls before a sudden gust load can drive the structure past its limit, so the airframe is protected from an abrupt vertical gust.
Gust loads add to the load already on the wing, so the FAA tests the speed that keeps a sudden gust from overstressing the airframe and how that speed changes with weight.
Maneuvering speed is not a fixed number. It decreases as weight decreases, so a lighter airplane must slow more, not less, for the same gust protection.
Where to study it
A code on your test report is an area of deficiency. An authorized instructor must review it with you and endorse that review before you take the practical test, and the examiner may revisit it during the oral. Study it until you can explain it out loud, not just recognize the answer.