What is the minimum RPM required for an aerial restart?

What is the minimum RPM required for an aerial restart?

• A. 9% RPM
• B. 12% RPM
• C. 15% RPM
• D. 20% RPM

Answer: (B)

When you attempt an aerial restart, the engine must be turning fast enough to deliver sufficient air through the compressor and to power the ignition system. The minimum RPM is the lowest nonzero spool speed at which light-off can occur and be sustained. If you’re below this threshold, there isn’t enough air or ignition energy for the fuel to ignite; the engine won’t relight. If you’re above it, you’ve passed the point where light-off is reliably achievable at that moment, and you risk unstable light-off or other issues. So the correct choice reflects that smallest nonzero RPM needed to achieve a reliable light-off, rather than a speed that’s too low to ignite or too high to manage safely.

When you attempt an aerial restart, the engine must be turning fast enough to deliver sufficient air through the compressor and to power the ignition system. The minimum RPM is the lowest nonzero spool speed at which light-off can occur and be sustained. If you’re below this threshold, there isn’t enough air or ignition energy for the fuel to ignite; the engine won’t relight. If you’re above it, you’ve passed the point where light-off is reliably achievable at that moment, and you risk unstable light-off or other issues.

So the correct choice reflects that smallest nonzero RPM needed to achieve a reliable light-off, rather than a speed that’s too low to ignite or too high to manage safely.