A strong cold front lay between
southern Kansas and northern Nebraska on the evening of August 6,
1966. Braniff flight 250 was scheduled to depart Kansas City for
Omaha shortly before 11:00pm that night with 38 passengers and two
flight attendants. On the flight deck of the BAC-111 was Captain D G
Pauly and First Officer J A Hilliker. Pauly's weather report said
that the front was moving southeast, it's passage bringing severe
thunderstorms, hail, and strong wind gusts. Another crew just in
from Chicago told him that the storm front looked very severe and
that that radar pictures did not accurately portray it's intensity.
Upon departure, 250 was told to climb and maintain 5,000ft. A few
minutes after takeoff, the flight was handed off to Kansas City
Centre and cleared to FL200.
Pauly then told Centre that he would prefer to
maintain 5,000ft and asked to deviate left of the flight plan
course. This request was granted and 250 was handed off to Chicago
Centre. Pauly discussed the weather with the Chicago controller and
then spoke with another Braniff flight which was at that time
climbing out of Omaha for Kansas City. The crew reported light to
moderate turbulence and reported that their weather radar showed
nothing of significance further south.
Pauly acknowledged and that was the last heard
from 250. Shortly afterwards, several people on the ground who had
gone outside to view the approaching storm reported seeing 250
flying in clear conditions at about 4,000ft. Witnesses said it
seemed to be heading for a light spot in the approaching cloud wall.
250 was lost from view as it passed over a low cloud shelf, but
shortly thereafter, witnesses reported seeing a bright flash and a
ball of fire falling through the cloud shelf which was 205
spiralling towards the ground, where it impacted killing all aboard.
Just moments after the crash, the wind shifted nearly 180 degrees
and increased velocity to about 50kts. Rain began to fall and,
within minutes, two funnel clouds had formed.
......Examination of the wreckage showed that the starboard wing
failed downward while the tail had failed to the left. Both the
rudder and elevator had separated from their attachments, having
over-travelled in both directions. There was no evidence of
structural or system damage nor damage from hail or lightning. The
FDR was destroyed in the fire, but the CVR was still readable. The
pilots discussed a hole in the line of clouds ahead and then talked
about diverting to Pawnee City. About half a minute later, the words
"Ease the power back" were heard, followed by the sound of rushing
which continued until the end of the tape 25 seconds later. Just
prior to the end of the tape, the stall warning horn was heard four
times.
Analysis of the CVR showed that the aircraft was
travelling at approximately 270kts, it's recommended turbulence
penetration speed. It was determined that 250 would have to
encounter a gust of at least 140ft/sec. at an upward angle to cause
the tailplane to fail. Chicago Centre's radar tape showed an area of
heavy rain just north of the area of the accident. The U.S. Weather
Bureau analysed the weather in the area and confirmed that strong
outflow from the rain cell north of the accident area would cause
extreme low-level turbulence. Further analysis showed that 250 would
have just passed through a low-level shear zone when the accident
happened.
The other Braniff flight penetrated the line just
east of 250's flight path at cruising altitude and experienced no
problems.