Continental 727 Crashes in DenverBy Patrick Mondout
At just after 4 p.m. on August 7, 1975, Continental
Airlines Flight 426 crashed after takeoff from the Denver's Stapleton
International Airport. All 134 persons aboard the aircraft survived the
crash though 15 persons were injured seriously.
The Boeing 727
climbed to about 100 feet above runway 35L and then crashed near the
departure end of the runway. The aircraft was damaged substantially.
At the time of the accident, a thunderstorm with associated rain
showers was moving over the northern portion of the airport. The
thunderstorm was surrounded by numerous other thunderstorms and associated
rain showers but none of these were in the immediate vicinity of the
airport.
The National Transportation Safety Board determined the probable cause
of this accident was the aircraft's encounter, immediately following
takeoff, with severe wind shear at an altitude and airspeed which
precluded recovery to level flight; the wind shear caused the aircraft to
descend at a rate which could not be overcome even though the aircraft was
flown at or near its maximum lift capability throughout the encounter. The
wind shear was generated by the outflow from a thunderstorm which was over
the aircraft's departure path.
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Continental
727 |
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What's left of
Continental's N88777 as seen in the Mohave desert
in 1984.
Image courtesy of AirNikon.
Find more of his photos at Airliners.net. |
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Two flights preceded Continental 426 on the takeoff from runway 35L.
About 4:05, the local controller cleared Braniff
International Flight 67, a Boeing 727-100, for takeoff; he reported
that the winds were 250" at 15 knots with gusts to 22 knots. At
4:06:33, Braniff 67 reported, "OK, you got some pretty good up and
downdrafts out here from two, three hundred feet." The local
controller acknowledged Braniff 67's report. Continental 426 did not
receive Braniff 67's report, because the flights were on different radio
frequencies.
About 4:07, the local controller cleared Frontier
Airlines Flight 509, a Convair
580, to takeoff on runway 35L. The controller informed Frontier 509 that
the winds were 280" at 13 knots with gusts to 22 knots and that
Braniff 67 had reported updrafts and downdrafts at 200 to 300 feet.
Frontier 509 acknowledged the information. Continental 426 also did not
receive this information, because it was operating on the ground control
frequency.
At 4:08:58, Continental 426 informed the local controller that it was
ready for takeoff. The local controller cleared the flight to hold in the
takeoff position.
At 4:09:15, Frontier 509 reported, "...there's a pretty good shear
line there about halfway down 35." The local controller responded,
"...you got an altitude on it?" Frontier 509 replied, "Oh
about just like that other airplane called it, about 200 feet." At
4:09:31, Continental 426 transmitted, "426 copied."
A 4:10:11, the local controller cleared Continental 426 for takeoff. He
informed the flight that winds were 230° at 12 knots and, "there
have been reports of pretty stout up and downdrafts and that shear out
there at 200 to 300 feet." The flight acknowledge the clearance and
the information.
The crew of Continental 426 used maximum takeoff thrust and later
stated that all instrument readings were normal when a check was made at
80 knots.
According to first officer Robert W. Shelton, the aircraft left the
runway just after it passed over the interstate highway, which was 4760
feet from the threshold of runway 35L. He saw a positive rate of climb and
at 4:11:05 he called, "gear up." Captain Robert E. Pries said
the aircraft entered heavy rain about the time the first officer executed
the rotation maneuver (which raises the nose for takeoff). Captain Pries
turned on the windshield wipers and, in response to the first officer's
command, the moved the gear hand to the up position.
According to the flightcrew, the aircraft climbed normally to 150 to
200 feet above the runway. The captain the felt the aircraft sink and saw
that the airspeed was reduced. He took control of the aircraft, advanced
the power levers to maximum thrust, and lower the nose. The aircraft
continued to descend, and the captain attempted to increase the pitch
attitude.
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Continental
727-224 |
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Another Boeing 727-224,
similar to Flight 426 as seen at Denver's
Stapleton Airport in January 1975.
Image courtesy of AirNikon.
Find more of his photos at Airliners.net |
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The aircraft struck the ground at 4:11:18 on the right shoulder of
runway 35L, just south of the departure end of the runway. It slid almost
2000 feet and came to rest on an airport road.
Six passengers received lumbar or thoracic vertebral fractures; on of
these passengers also received serious injuries to her right leg and both
of her feet. Two passengers received fractured ankles. Two passengers, one
of whom also had a severe neck strain, were hospitalized for more than 48
hours with multiple contusions, abrasions, and bruises.
According to second officer William R. Kocar, when the aircraft came to
rest he heard a loud explosive sound and screaming from the passenger
cabin. He said he was dazed and shaken and that he attempted to open the
cockpit door, "but I don't know what I was holding onto when I was
trying to open it; I don't know if I had the door knob." He then
yelled "Fire, let's get out of here!" because he thought the
aircraft was on fire (miraculously, it was not).
After the captain tried to shut off the aircraft engines, he escaped
through the left cockpit sliding window; Kocar and Shelton escaped through
the right cockpit window. They then assisted passengers escaping off the
wings.
The captain returned to the cockpit through the left cockpit window and
again tried unsuccessfully to shut off the engines. He then opened the
cockpit door and assisted one of the forward flight attendants from under
the coat closet and directed the other out the right cockpit window. He
left the aircraft and discussed the engine problems with firemen, who had
responded to the crash alarm. The captain once again returned to the
cockpit but could not shut off the engines. The firemen then injected fire
extinguishing foam and water into the engines and they stopped.
Source: Adapted from National Transportation Safety Board (NTSB)
report NTSB-AAR-76-14.
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