What is the minimum separation required between aircraft on crossing runways to avoid wake turbulence?

• A. 1 minute
• B. 3 minutes
• C. 2 minutes
• D. 5 minutes

Answer: (C)

The minimum separation required between aircraft on crossing runways to avoid wake turbulence is indeed two minutes. This time interval is established to mitigate the risks associated with wake turbulence, which can be particularly hazardous during takeoff and landing phases when aircraft are transitioning from ground to air or vice versa.

Wake turbulence is generated by an aircraft as it generates lift, predominantly affecting the trailing aircraft that may be departing or landing on a crossing runway. Factors such as the type of aircraft and its weight significantly influence the strength of this turbulent wake. The two-minute separation allows sufficient time for the induced turbulence to dissipate before the subsequent aircraft enters the area where the wake could affect its performance.

Shorter separation intervals could lead to significant risks, especially if a heavy aircraft precedes a lighter one, as the wake might still be strong enough to cause control difficulties for the following aircraft. Thus, regulatory guidelines in air traffic control are implemented to ensure a minimum of two minutes between such operations on intersecting runways, striking a balance between efficiency and safety in airspace management.