Narrative:

Runway change in progress. Aircraft was 'line up and wait' on runway 31L. Aircraft crossing midfield to runway 4L. Waiting aircraft was cleared for take off. Pilot responded 'after traffic clears; cleared for take off.' aircraft crossing down field appeared on asde-X to be clear/clearing runway 31L.

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Original NASA ASRS Text

Title: JFK Controller cleared an Air Carrier for departure as traffic crossing down field was clearing according to ASDE-X; the pilot commenting that take off would commence after traffic cleared.

Narrative: Runway change in progress. Aircraft was 'line up and wait' on Runway 31L. Aircraft crossing midfield to Runway 4L. Waiting aircraft was cleared for take off. Pilot responded 'after traffic clears; cleared for take off.' Aircraft crossing down field appeared on ASDE-X to be clear/clearing Runway 31L.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.