UAL433, a DC10, executes a missed approach on Runway 28R. N310MN, a C310, is waiting to depart at the approach end. N310MN may start takeoff roll ___.

• A. 2 minutes after UAL433 crosses the landing threshold
• B. 1 minute after UAL433 crosses the landing threshold
• C. 3 minutes after UAL433 crosses the landing threshold
• D. 2 minutes before UAL433 crosses the landing threshold

Answer: (A)

The main idea is wake turbulence and runway separation when a following aircraft is waiting to depart behind a preceding arrival that used the same runway. After a heavy aircraft performs a landing or missed approach, a light departure at the approach end must wait long enough for the heavy’s wake to dissipate and for the runway to be clear. The standard margin here is 2 minutes after the preceding aircraft crosses the landing threshold. That moment marks when the heavy’s path is past the critical portion of the runway, and the wake has dissipated enough to permit a safe takeoff roll by the following light aircraft.

So, starting two minutes after UAL433 crosses the threshold provides the required safety buffer without unnecessary delay. Starting earlier would risk wake effects or runway conflicts; waiting longer than two minutes would be extra delay without added safety in this scenario.