Definition
An FAA requirement that air traffic controllers must issue a specific clearance for each runway a pilot is expected to cross while taxiing, and pilots must read back that clearance. A single taxi clearance does not authorize crossing any runway along the route; each runway crossing requires its own explicit instruction, given one runway at a time. The crossing clearance is normally issued only when the aircraft is approaching the runway to be crossed.
Plain English
When you taxi, you cannot cross any runway unless the controller specifically tells you to cross that exact runway. You must read the instruction back. Even if the controller has cleared you to taxi to a destination, you still have to wait for a separate, named clearance for each runway in your way.
Context Anchor
Encountered during ground operations at towered airports, especially while taxiing from parking to a runway or after landing and taxiing to parking.
Derivation
Explicit comes from the Latin explicitus, meaning 'unfolded' or 'made plain.' In ATC use, it emphasizes that the runway crossing must be stated openly and individually—not implied or bundled into a longer taxi instruction.
Why Pilots Care
Ensures pilots never cross a runway without positive clearance, directly reducing the risk of runway incursions.
Intuition Check
Wrong assumption: “ATC gave me a taxi route, so I can cross any runway along that route.” Correct idea: You need a specific instruction to cross each runway, such as “Cross Runway Two Seven.”
Example Sentence 1
After receiving 'Taxi to Runway 27 via Alpha,' the pilot held short of Runway 15 and waited for the controller to issue an explicit runway crossing instruction before continuing.
Example Sentence 2
The pilot held short of the runway because the taxi clearance did not contain explicit crossing instructions.