Airbus A321 231 N587NK incident near Fort Lauderdale, Florida

Probable cause

The air traffic controller's failure to ensure the runway surface area was clear of vehicles before clearing an aircraft for takeoff. Also causal was the flight crew's decision to initiate a takeoff while the Runway Status Lights (RWSL) Takeoff Hold Lights (THLs) were activated. Contributing to the incident was the lack of a standard procedure for vehicle operators to request runway clearances and resultant "hear back/read back" error between the vehicle operator and the air traffic controller.

NTSB analysis

The runway incursion occurred during the early morning hours when traffic was light, and when the airport authority usually conducted maintenance activities on the airfield. The air traffic controller approved a request by an airport maintenance vehicle to operate on the runway; however, there were no standard operating procedures or standard phraseology regarding how airfield vehicle operators were to reference the specific runway end when requesting permission to enter a runway. This lack of standard procedure resulted in four hear back/read back errors between the operator of the vehicle and the air traffic controller immediately prior to the runway incursion event.

After the airport vehicle had been approved by the air traffic controller to operate on the runway, the crew of the A321 requested a clearance to taxi to the same runway for departure and was subsequently cleared for takeoff. The airport runways and taxiways were equipped with the Runway Status Light (RWSL) system. As the crew of the A321 aligned with the runway centerline for departure, the Takeoff Hold Lights (THL) portion of the RWSL activated, displaying red lights on the runway surface. The crew continued the takeoff over the illuminated RWSL system. The RWSL system was operating correctly and the THL portion of the system deactivated when the A321 reached a predetermined speed consistent with an aircraft continuing departure.

As the A321 was departing, the Airport Surface Detection Equipment Model X (ASDE-X) alerted and the air traffic controller responded by cancelling the takeoff clearance when the A321 was near takeoff speed. The A321 stopped on the runway about 500 feet from the airport vehicle.

Text from the NTSB. Open the NTSB docket for OPS16IA004 for the full record.