What did the two vehicles on Taxiway Delta request in the CMA escort example?

• A. To cross Runway 21R
• B. To land on Runway 21R
• C. To exit Runway 21R
• D. To stop and wait

Answer: (A)

Crossing an active runway requires explicit permission from ATC. In a CMA escort, vehicles on Taxiway Delta must obtain a crossing clearance before moving onto or across Runway 21R to ensure there’s no conflict with arriving or departing aircraft. The two vehicles were requesting permission to cross Runway 21R so they could proceed to the other side or reach their destination safely. This is different from wanting to land on the runway, exit it after landing, or simply stop and wait, which would involve different ATC actions. The key idea is that runway crossings are authorized movements that depend on ATC coordination to keep all aircraft and ground traffic separated.