In the wake turbulence scenario, the required separation is counted after which event?

• A. rotation
• B. takeoff clearance
• C. touchdown
• D. taxiing

Answer: (A)

In wake turbulence cases, the important moment for establishing required separation is when the lead aircraft rotates and becomes airborne. That moment marks when the strong wake vortices begin to trail behind the aircraft in a consistent, hazardous way, so the trailing aircraft must not be put into the same airspace until a safe interval has passed from that instant.

Counting separation from rotation makes sense because before rotation the vortices are not in the stabilized wake behind an issuing liftoff, and the following aircraft isn’t yet in the most dangerous part of the wake path. After rotation, the vortices settle into a predictable pattern behind the aircraft, so spacing can be accurately enforced.

Taking off clearance happens before liftoff and doesn’t anchor the hazard window; touchdown is relevant for arrivals, not the takeoff wake interaction described here; taxiing is unrelated to the wake development that occurs during takeoff.