The aviation industry has witnessed a concerning increase in runway incursions involving business jets, primarily due to misunderstandings of “line up and wait” (LUAW) instructions from air traffic control (ATC). Runway safety has become a significant focus this year, with a notable rise in the most severe type of runway incursions, known as Category A incidents. These incidents narrowly avoid collisions between two aircraft, prompting concerns from aviation safety organizations, including the National Transportation Safety Board (NTSB) and the Federal Aviation Administration (FAA), about the potential for actual collisions.
On October 24, these concerns materialized when two business jets collided at Houston Hobby Airport (KHOU). During this incident, a Hawker 850XP, in the midst of takeoff, struck a Cessna Citation Mustang that was landing on a crossing runway. Alarmingly, the Hawker’s pilots failed to follow ATC’s “line up and wait” instructions and disregarded two urgent requests from the local tower controller to abort the takeoff, resulting in substantial damage to both aircraft. Fortunately, there were no injuries to any occupants.
According to the preliminary accident report by the NTSB, the tower controller instructed the Hawker pilots to “line up and wait” on Runway 22. In a post-accident interview, the Hawker pilots indicated that they believed they had been cleared for takeoff.
FAA records of communications reveal that as the Hawker approached Runway 22, the ground controller instructed the pilots to monitor the tower frequency. Just before reaching the runway, the displayed V-speeds disappeared from the flight display screens, as stated by the Hawker pilots during the post-accident interview.
Shortly after, the tower controller instructed the Hawker crew to “line up and wait” on Runway 22, to which the pilots acknowledged. The tower controller did not provide any traffic advisories to the Hawker, which was not mandatory.
Meanwhile, the Cessna Citation was on a short final approach to Runway 13R, which intersects with Runway 22. Both runways are 7,602 feet long, with the intersection approximately midway down Runway 22.
As the Hawker approached Runway 22, it unexpectedly initiated its takeoff roll. At this point, another controller in the tower, handling clearance delivery, noticed the Hawker’s movement and alerted the tower controller. Despite the tower controller’s immediate instructions to “stop, hold your position,” there was no response from the Hawker’s crew. Even after a repeated command, the Hawker continued its unauthorized takeoff and collided with the Citation.
In the aftermath of the collision, the Hawker crew completed their takeoff and promptly returned to Houston Hobby, landing on Runway 13R, while the Citation cleared the runway.
A post-accident examination revealed significant damage to the Hawker’s left winglet and wing leading edge surfaces, while the Citation suffered substantial damage to its empennage, including the tail cone, rudder, and structural elements.
The Houston Hobby incident follows a similar event that occurred eight months earlier at Boston Logan International Airport (KBOS). In that case, the flight crew of a JetBlue Embraer 190 executed a go-around to avoid a Bombardier Learjet 60, which had begun its takeoff from an intersecting runway without clearance. The aircraft passed within 30 feet of each other.
The incidents underscore the critical importance of understanding and adhering to “line up and wait” instructions from ATC. The FAA introduced this phraseology in September 2010 to align with international standards and address runway incursion issues. The instruction to “line up and wait” is used to position an aircraft onto the runway for immediate departure, but it does not authorize takeoff.
Pilots should exercise heightened situational awareness during LUAW operations by monitoring ATC instructions/clearances issued to other aircraft. They should also pay close attention to communications between ATC and other aircraft, especially those with similar callsigns. Prior to taxiing onto or crossing a runway, pilots should visually scan the full length of the runway, particularly at night or in reduced visibility conditions.
Furthermore, it is crucial to make the aircraft visible to ATC and other aircraft during LUAW operations by turning on all exterior lights (except takeoff/landing lights). When multiple runways are active at larger airports, pilots must listen attentively for their specific callsign and runway, being cautious of similar-sounding callsigns. If in doubt, pilots should promptly seek clarification from ATC.
ATC plays a vital role in preventing runway incursions, and they are responsible for informing aircraft holding in position about the closest aircraft within six flying miles on approach to the same runway (not crossing runways). It is essential for pilots to note the position of landing traffic and for ATC to notify landing traffic when an aircraft is authorized to “line up and wait” on the same runway.
Runway incursions pose a significant threat to aviation safety, and vigilance, communication, and adherence to procedures are essential to mitigating this risk.
Sources: AirGuide Business airguide.info, bing.com, ainonline.com
