Southern
Airways flight 242 was operating from
Huntsville to Atlanta on the afternoon
of April 4, 1977. On the flight deck of
the DC-9 that day was Captain Bill
McKenzie and First Officer Lyman Keele.
Two flight attendants and 81 passengers
were also aboard for the short flight.
The weather that afternoon was far from
pleasant, the area forecast predicting
scattered thunderstorms, some severe
with icing, turbulence, and hail. There
were two Tornado Watches in effect as
well as a SIGMET predicting severe
thunderstorms reaching up to 58,000ft
extreme turbulence, wind gusts in excess
of 70kts, and large hail.
The crew had
flown the same route outbound earlier
and had experienced heavy rain and hail,
not pleasant, but by all means
manageable. The forecast for their
arrival in Atlanta called for overcast
layers down to 2700ft and winds gusting
to 40kts. At 3:54pm, with rain falling,
242 departed Huntsville. Four minutes
later, they were handed off to Atlanta
Centre. Atlanta Centre was at the time
talking to TWA and Eastern flight crews
who were passing through the SIGMET
area.
The
Eastern crew reported that the ride
"...wasn't too comfortable, but we
didn't get into anything we would
consider the least bit hazardous." A few
minutes later, 242 was instructed to
descend and maintain 14,000ft. The crew
acknowledged, but four further
transmissions went unanswered, finally
answering "standby" to a fifth call.
Atlanta then instructed 242 to maintain
15,000ft to which the crew replied "OK..we
just got our windshield busted
and...we'll try to get it back up to
15...we're 14." Crash Site of 242.
This was followed shortly by "Our left
engine just cut out." Thirty seconds
later, the crew reported "The other
engine's going too!" 242 asked for an
immediate vector to a clear area and
Atlanta instructed the crew to maintain
it's present heading and contact Atlanta
Approach. Atlanta continued to try to
contact 242, but in the next three
minutes, all of it's calls went
unanswered. Then 242 came up on Approach
frequency reporting that it had lost
both it's engines and needed a vector
from it's present position at 7,000ft.
Approach instructed 242 to turn right to
a heading of 100 for a straight-in
approach to runway 11 at Dobbins Air
Force Base. At this point, 242 was 20
miles west of Dobbins.
After several
minutes of continued discussion with
Atlanta Approach, after descending
through 4,600ft, 242 asked if there was
a closer airport than Dobbins. Approach
responded that Catersville airport was
currently 10 miles north of 242's
position and 242 asked to be vectored
towards it. 242 was instructed to turn
left to 360 and asked for information on
the airport. Just after Approach
finished reporting the information on
Catersville, 242 replied with "We're
putting it on the highway...we're down
now to nothing!" 242 was now descending
over Georgia's State Highway 92, a
narrow two lane highway flanked on both
sides by tall pine trees. The DC-9
clipped a tree with it's port wing and
then struck an embankment, breaking up
and bursting into flames and ploughing
into a service station before coming to
a stop. Of the 81 passengers on board,
60 were killed along with the pilots and
eight people on the ground.
......Recovery of the wreckage showed
extensive hail impact on the tail
surfaces and engine nacelles. The fan
blades of both engines showed denting
due to hail as well. The low-pressure
compressors were severely damaged, with
bent and broken blades. In addition, the
turbines had overheated. Wreckage of 242
One of the survivors reported there was
severe turbulence and heavy rain
followed by a lightning strike on the
port wing and hail. He also reported
hearing popping and surging before the
engines failures. Water ingestion tests
of the engines showed that, at flight
idle, ingestion rates of over 18% caused
the engine rpm to decrease sufficiently
to cause generator cutout. This was
evident in two power losses recorded on
the FDR and CVR. In addition, test
showed that, if the throttle was
advanced to a high power setting, the
resulting surge could cause bending and
breaking of the low-pressure compressor
blades.
This was evidenced in the engine
by damage of the blades and subsequent
ingestion of the fragments into the
high-pressure compressor, causing engine
failure. The turbine overheat damage was
produced by high-power settings after
compressor damage. It was therefore
determined that heavy rain ingestion,
not hail ingestion, was responsible for
the engine failure. Review of the radar
images of the accident area and the FDR
showed that 242 actually flew right
through the most severe part of the
thunderstorm. 242 was equipped with
weather radar, but the CVR picked up
discussion of a "hole" just prior to the
cell penetration. It is thought that
what the crew saw was a "contour hole",
caused by the intensity of the rainfall
being so severe that the weather radar
could not accurately display it.
This
phenomenon apparently misled the crew
into thinking they could penetrate the
storm front through a hole. The National
Weather Service had detailed information
about the storm area which was available
prior to 242's departure from Hunstville,
but Southern's dispatch office was
unaware of the the storm data and did
not pass anything on to 242.