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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] pilots 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), "Theyre both using 04. Youre planning on one three
still, right?" The F/O replied, "Yeah, unless it doesnt look
good then well 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. Well 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 "shes 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] pilots 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 Foundations
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://www.flightsafety.org/pubs/ap_1998.html,
or obtain a copy of NTSB Report NTSB/AAR-97-04.
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