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Intersecting Runway Collision

Intersecting Runway Collision

On November 19, 1996, a Beechcraft 1900C (B1900) with ten passengers and two pilots was making a straight-in approach at dusk in visual meteorological conditions (VMC) to Runway 13 at Quincy (Illinois, U.S.) Municipal Airport, an uncontrolled airport. A King Air 90 (BE90) with a pilot and passenger-pilot was in takeoff position on Runway 04, which intersected Runway 13. Waiting in the run-up area, second in line for takeoff behind the BE90, was a Piper Cherokee (PA-28). Several seconds before the B1900 touched down on Runway 13, the BE90 began its takeoff run on Runway 04. Despite evasive action by the pilots of both aircraft (a/c), they collided at the intersection of the two runways, killing all aboard. The occupants did not sustain blunt-force injuries that would have impeded their ability to move about or evacuate the a/c, but died from inhaling smoke, soot or other combustion products from the post-accident fire.

The final report of the U.S. National Transportation Safety Board (NTSB) said that "the probable cause of this accident was the failure of the pilots in the [BE90] to effectively monitor the common traffic advisory frequency (CTAF) or to properly scan for traffic, resulting in their commencing a [take-off] roll when the [B1900] was landing on an intersecting runway. Contributing to the accident was the [PA-28] pilot’s interrupted radio transmission, which led to the [B1900] pilots’ misunderstanding of the transmission as an indication from the [BE90] that it would not take off until after the [B1900] had cleared the runway."

The sequence of events — The captain of the B1900 stated on the CTAF that they were about 30 mi. north of the airport and that they would be landing on Runway 13; she also asked that "any traffic in the area please advise." No replies were received to this request. CTAF is a radio frequency designated for use by pilots operating near uncontrolled airports, similar to mandatory frequencies (MF) in Canada. Pilots use this frequency to broadcast their positions or intended flight activities or ground operations.

The passenger-pilot of the BE90 announced that they were taxiing out for takeoff on Runway 04; this was followed by the pilot of the PA-28 announcing that he was "back-taxiing" to Runway 04. The B1900 captain commented to the first officer (F/O), "They’re both using 04. You’re planning on one three still, right?" The F/O replied, "Yeah, unless it doesn’t look good then we’ll just do a downwind for four but ... right now plan one three."

The B1900 captain announced "Quincy traffic, [call sign] is currently 10 mi. to the north of the field. We’ll be inbound to enter on a left base for Runway one three at Quincy, any other traffic please advise." There was no response. Two minutes later, the BE90 crew announced that they were holding short of Runway 04, but would be taking the runway for departure. The report said, "The [B1900] captain...commented "she’s takin’ Runway four right now?" The F/O replied, "Yeah."

The B1900 captain reported on short final for Runway one three and asked "the a/c gonna hold in position on Runway four or you guys gonna take off?" The BE90 passenger-pilot did not respond, but the pilot of the PA-28 did, stating, "[PA-28 call sign] ... holding ... for departure on Runway four..." The B1900 CVR [cockpit voice recorder] then recorded an interruption in the transmission by a mechanical "two hundred" from their ground-proximity warning system. The CVR then recorded the last part of the transmission from the PA-28 as "...on the uh, King Air."

When the PA-28 responded to the question, the B1900 captain believed that she was hearing the King Air crew. The NTSB, however, reports that subtle cues indicated that the transmission did not come from the BE90. Specifically, the speaker gave a different registration number, and the voice was from a male, as opposed to previous transmissions from a female voice in the BE90. ... The PA-28 pilot stated that all the transmissions from both the B1900 and the BE90 were in female voices. "However, because the [B1900] pilots were most likely preoccupied with landing the a/c, and because the speaker said "King Air" and did not say "Cherokee," and the pilots had no reason to expect a response from any a/c other than the BE90, they probably did not notice or focus on those cues."

Although the BE90 had been sitting on Runway 04 for about one minute, the BE90 pilot began the takeoff without making a take-off announcement over the CTAF. Such an announcement would have afforded the B1900 flight crew the opportunity to take evasive action. The PA-28 pilot, who had only 80 hrs of flight time, saw the two airplanes converging, and had the opportunity to alert the B1900 to the situation, which would have been prudent. Despite the 90-degree angle between Runways 04 and 13, the PA-28 pilot stated he did not realize that the runways intersected.

"Because no pilot would take off knowing that another a/c was about to land on an intersecting runway, the occupants of the BE90 must have been unaware at the time they began their [take-off] roll that an a/c was about to land." This lack of awareness could have derived from three sources: failure of the BE90 pilots to monitor the CTAF, mechanical radio problems or the setting of the radio controls on the King Air so the flight crew could transmit but not receive.

"Had the occupants of the BE90 been monitoring the CTAF, they should have heard the four announcements from the B1900 indicating that the a/c was inbound and was planning to land on Runway 13. Because of the extensive fire damage, the settings on the radios at the time of the accident could not be determined."

A time and distance study conducted by the NTSB indicated that the BE90 began its take-off roll about 13 seconds before the B1900 touched down. The occupants of the PA-28 said that the BE90 had been in position on Runway 04 for about one minute before beginning its take-off roll. The PA-28 pilot did not hear a take-off announcement from the BE90 on the CTAF; no take-off announcement from the BE90 was recorded on the B1900 CVR.

The B1900 collided with the BE90 during the landing roll-out at the intersection of Runways 13 and 04. The first people to reach the scene reported that the right side of the B1900 and the BE90 were engulfed in fire. Despite efforts by these people to open the B1900 air-stair door, they were unable to do so. The investigation focussed extensively on the air-stair door, how and why it jammed, its use in an emergency, why nobody could open it from either inside or outside, and its maintenance. "The most likely reason that the air-stair door could not be opened is that the accident caused deformation of the door/frame system and created slack in the door-control cable."

The following are significant excerpts from the NTSB conclusions:

  • "The [B1900] crew made appropriate…radio communications and visual monitoring; however, they mistook the [PA-28] pilot's transmission (that he was holding for departure on Runway 04) as a response from the [BE90]..., and therefore mistakenly believed that the [BE90] was not planning to take off until after they had cleared the runway;
  • "The failure of the [BE90] pilot to announce over the [CTAF] his intention to take off created a potential for collision between the two [a/c];
  • "The occupants of the [BE90] did not hear the transmissions from the [B1900] on the [CTAF]; it is likely that ... the [BE90] occupants did not properly configure the radio switches..., or that they were preoccupied, distracted or inattentive;
  • "The occupants of the [BE90] were inattentive to or distracted from their duty to ‘see and avoid’ other traffic;
  • "The [PA-28] pilot's transmission in response to the [B1900] was unnecessary and inappropriate and... misled the crew into believing that the [BE90] would continue holding;
  • "Because of the [PA-28] pilot’s inexperience, he probably did not realize that a collision between the two a/c was imminent, and therefore he did not broadcast a warning; [and]
  • "The occupants of the [B1900] did not escape because the air-stair door could not be opened, and the left overwing exit hatch was not opened."

As a result of the investigation, the NTSB made recommendations to the Federal Aviation Administration on scanning techniques during pilot training and biennial flight reviews, jamming of the B1900 door frame system when it sustains minimal permanent door deformation, methods to ensure compliance with the freedom-from-jamming certification requirements and maintenance oversight.

Editorial note: The many lessons to be drawn from this accident are of interest to all pilots, but, owing to space limitations, we had to focus on the communication and "see-and-avoid" aspects in an uncontrolled environment. Issues such as the jamming of the B1900 air-stair door and the crash response could not be discussed as comprehensively as in the Flight Safety Foundation’s newsletter Accident Prevention, Vol. 55 No. 1, January 1998, from which this article was adapted. Interested readers are encouraged to check it out on the Web at http://flightsafety.org/archives-and-resources/publications/accident-prevention/accident-prevention-1998, or obtain a copy of NTSB Report NTSB/AAR-97-04.