When can N1388V, a C421, depart after SWA601, a B737, executes a missed approach?

The correct answer is based on the need to maintain safe separation between departing and arriving aircraft, particularly after a missed approach. In this scenario, N1388V, a C421, can depart after all runway separation requirements are met.

Runway separation standards are established to ensure that a safe distance exists between aircraft, minimizing the risk of wake turbulence encounters or collision. This requirement is critical after a missed approach, where the operational dynamics can rapidly change as the lead aircraft (SWA601 in this case) may still be maneuvering in the airspace.

The other choices present various timeframes or actions related to the position of the B737 after its missed approach. However, simply relying on those specific time intervals or procedural positions does not guarantee that the separation requirements are met in all situations. Instead, the procedure emphasizes the importance of confirming that the proper distance has been established before allowing any subsequent departures to ensure safety in the airspace system. Thus, once the separation requirements have been satisfied, N1388V can safely depart.