Runway safety has been a hot topic this year. In fact, year-to-date data shows an increase in the most serious type of runway incursions—Category A incidents, where a collision between two aircraft was narrowly avoided. Aviation safety organizations, including the NTSB and FAA, are concerned with the increase in the number of near collisions and many have feared the worst—an actual collision between two aircraft.
On October 24, these concerns were realized when two business jets collided at Houston Hobby Airport (KHOU). During this event, the crew of a Hawker 850XP on takeoff roll struck a Cessna Citation Mustang that was landing on a crossing runway. Alarmingly, the Hawker pilots did not follow ATC instructions to “line up and wait” (LUAW) and ignored two pleas by the local tower controller to abort the takeoff run before impact. Both aircraft were substantially damaged. Fortunately, none of the occupants were injured.
According to the NTSB preliminary accident report, the tower controller instructed the pilots of the Hawker to LUAW on Runway 22. In a post-accident interview, the Hawker pilots said they believed that they were cleared for takeoff when they took off.
The FAA record of communications indicates that, as the Hawker approached Runway 22, the ground controller instructed the pilots to monitor the tower frequency. Just prior to reaching the runway, the V-speeds were no longer displayed on the flight display screens, the Hawker pilots stated in the post-accident interview.
Shortly afterwards, the tower controller instructed the Hawker crew to LUAW on Runway 22, which the pilots acknowledged. The tower controller did not provide any traffic advisories to the Hawker, nor was he required to.
A Problem in Houston
At this point, the Cessna Citation was on a short final to Runway 13R that intersects Runway 22. Each runway is 7,602 feet long, and the intersection of the two runways is approximately halfway down Runway 22.
As the Hawker approached Runway 22, it unexpectedly began its takeoff roll. At this point, another controller in the tower working clearance delivery noted the Hawker’s movement and notified the tower controller. The tower controller immediately instructed the Hawker crew to “stop, hold your position.” There was no response. Again, the tower controller yelled, “Hold your position, stop,” to which there was no response.
The pilots may have been distracted. They stated that “they had a rudder bias alert and pitch trim alert that they had to resolve during the takeoff roll.” (Note: a lack of V-speeds displayed and two aircraft systems alerts annunciated suggests the aircraft was not properly configured or ready for takeoff.)
Of interest, the Hobby tower controllers noticed the movement of the Hawker a few seconds before the Airport Surface Detection Equipment (ASDE-X) installed at the airport did.
Less than two minutes after beginning its unauthorized takeoff, the Hawker’s left-wing tip struck the empennage of the Citation. Both pilots of the Hawker stated that they did not see the Citation until about one second before impact, and they described the feeling as a “thud.” The Citation pilot stated that he did not see the Hawker and described the impact as a “sound similar to a truck tire blowing.”
After the aircraft came into contact with each other, the Hawker crew continued their takeoff and immediately returned to Houston Hobby, landing on Runway 13R. The Citation cleared the runway.
A post-accident examination revealed significant damage to the Hawker’s left winglet and wing leading edge surfaces. The Citation had significant damage to its empennage, including the tail cone, rudder, and other structural elements.
Boston Close Call
Eight months before the runway collision in Houston, another business jet took off without a takeoff clearance at Boston Logan International Airport (KBOS). In this case, on February 27 the flight crew of a JetBlue Embraer 190 averted disaster by initiating a go-around while over Runway 04R at KBOS to avoid a Bombardier Learjet 60 that began its takeoff from intersecting Runway 09 without a takeoff clearance. The aircraft passed within 30 feet of each other.
According to the NTSB’s investigation report, the KBOS tower controller instructed the pilot of the Learjet to LUAW on Runway 09, while the JetBlue crew had been cleared to land on Runway 04R. ASDE-X alerted the tower of the impending conflict and the tower controller issued go-around instructions to the JetBlue crew.
The JetBlue pilots initiated the go-around during the landing flare over Runway 04R, before reaching the Runway 09 intersection. The JetBlue pilots recalled hearing ATC instructions for an aircraft to LUAW on Runway 09 and then seeing an aircraft cross in front of their aircraft, moving from left to right, before their go-around.
According to the Learjet captain, he “heard a clearance that seemed to be line up and wait” and responded to that clearance, “but in his mind, they were cleared for takeoff.” He added that they took off, and during cruise, they received a message from ATC with a phone number to call upon landing at their destination. After landing, KBOS tower informed the pilots that they had taken off without clearance, causing an airliner to conduct a go-around.
During a subsequent interview with the NTSB, the Learjet captain said, “I cannot understand what happened to me during the clearance. The only thing that comes to mind is that the cold temperature in Boston affected me…I was not feeling completely well and had a stuffy nose.” For whatever reason, both he and the first officer thought they were cleared for takeoff.
Line Up and Wait
The FAA adopted the phraseology “line up and wait” in September 2010. These words replaced “position and hold” to align with ICAO standards. This was in response to an NTSB recommendation to help curb the number of runway incursions that may have contributed to differences in terminology.
According to the FAA, LUAW is an air traffic control procedure designed to position an aircraft onto the runway for an immediate departure. The instruction to LUAW is used to instruct a pilot to taxi onto the departure runway and line up and wait, not take off.
Often a pilot is instructed to LUAW and advised of a reason or condition such as wake turbulence or traffic on an intersecting runway. Once that reason or condition is satisfied, pilots should expect an immediate takeoff clearance unless advised of a delay. If a pilot is uncertain about any ATC clearance or instruction, they must contact ATC immediately.
Likewise, if a takeoff clearance is not issued in a reasonable amount of time (90 seconds), a pilot should query ATC. FAA analysis of accidents and incidents involving aircraft holding in position on a runway indicates that, with two minutes or more of elapsed between the time of the ATC instruction to LUAW, the resulting event is likely either a “land-over” or go-around.
A Case for Defensive Flying
The FAA suggests that situational awareness can be enhanced during LUAW operations if pilots monitor ATC instructions/clearances issued to other aircraft. Pilots should also listen carefully if another aircraft is on a frequency that has a similar callsign, and they should pay close attention to communications between ATC and other aircraft.
Care must be taken to not inadvertently execute a clearance or instruction for another aircraft. Similar-sounding callsigns are problematic.
Pilots should always scan the full length of the runway for traffic before taxiing onto or crossing a runway. This is especially critical during LUAW operations at night or in reduced visibility conditions. Remember to make your aircraft visible to ATC and other aircraft. If cleared to LUAW, turn on all exterior lights except takeoff/landing lights.
At larger airports, when two or more runways are active, aircraft may be instructed to LUAW on multiple runways. Listen up! The FAA advises you to listen closely for your callsign and runway. Be alert for similar-sounding callsigns and always acknowledge with your full callsign. Again, when in doubt, ask ATC for clarification.
ATC is obligated to inform aircraft holding in position of the closest aircraft within six flying miles on approach to the same runway—not crossing runways. Pilots should take care to note the position of landing traffic. ATC will also advise the landing traffic when an aircraft is authorized to LUAW on the same runway.
Runway incursions are a threat to aviation safety. Earlier this year, I covered many of the fundamentals in a blog that supports the planning, communication, and coordination needed to avoid runway incursions. Recent incidents suggest that, as an industry, we have a long way to go.
The opinions expressed in this column are those of the author and not necessarily endorsed by AIN Media Group.