What is the turbulence penetration speed?

• A. 320 KIAS
• B. 280 KIAS/.75 Mach, whichever is lower
• C. 260 KIAS
• D. 0.78 Mach

Answer: (B)

When flying through turbulence you want to minimize gust-induced loads on the airframe while still keeping enough airspeed to maintain control. Turbulence penetration speed is the speed you select to pass through turbulent air so the structure isn’t stressed by sudden gusts, yet you don’t stall or lose control.

The standard rule is to fly at the lower of 280 knots indicated airspeed or Mach 0.75. This means you’re protecting against excessive dynamic pressure at lower speeds (which can cause higher gust loads) and against compressibility effects at higher speeds (Mach), choosing whichever limit is the stricter one for the current conditions. In practice, that keeps you safe across a range of altitudes and weights.

So the correct choice reflects that dual-limit guideline: 280 KIAS or Mach 0.75, whichever is lower. The other options don’t capture this combined criterion and could exceed the recommended gust-load protections in some conditions.