Which phraseology should be used to authorize an aircraft to cross a runway when safe?

• A. <Callsign>, Cross Runway <number> when able, Proceed as directed.
• B. <Callsign>, Cross Runway <number> now.
• C. <Callsign>, Cross Runway <number>, Do not proceed.
• D. <Callsign>, Cross Runway <number> after landing.

Answer: (A)

The main idea is using ATC phraseology that authorizes crossing a runway in a safe, controlled way while leaving room for follow-up instructions. Saying “Cross Runway when able” gives permission to cross, but only when it’s safe, preventing conflicts with traffic or runway occupancy. Adding “Proceed as directed” tells the pilot to follow any additional taxi instructions after crossing, ensuring they stay in line with the controller’s routing.

This combination is the best because it communicates both a conditional clearance (do it when it’s safe) and a clear expectation of further guidance. The other options either push for immediate action without safety tying the instruction to current conditions, or they give an instruction that doesn’t fit the taxi situation (like “do not proceed” or “after landing”).