Eighty-one passengers boards Southern Airways flight 242. A DC-9 bound for Atlanta, Georgia. Before the last take-off, the crew was handed a weather report for the airports along their route. The DC-9 was introduced in 1965 to fly frequent short flights. Both of its engines are mounted to the rear fuselage rather than wings. It was designed for take-off on shorter runways.
Skies have been smooth all afternoon, but the weather worsening. The flight crew is prepared for turbulence. At 3.54 p.m. the DC-9 takes-off into a hard rain. The short hop to Atlanta should take just 25 minutes. As Southern Airways 242 flies away from Homsvill the national weather service tracks weather that is far worse than the pilots expect. Tornados attaching down all across the south.
“The weather in the south-east of the U.S. can be very threatous. High humidity, high temperature are prescription for thunderstorms and so with all of the kind of moistening in the air and high convective heating you going to have very large thunderstorms. That are associated with heavy rain, hail, icing conditions and extreme wind.”
Hans Fill – air traffic controller has some concerns about gathering storm.
“Southern airways 242, I am painting a line of weather which appears to be moderate to possibly heavy precipitation.”
In 1977, most airliners are equipped with the bendix weather radar. Pilots are trained to avoid regions that appear bright. The pilots spotted dark area on the radar, a passageway through the storm. They planned to navigate between towering thunderheads over 14000 meters, but as they head towards the storm system, they get report from Memphis ATC.
“Attention, all aircraft SIGMET”. Sigmet is short significant meteorological information. It is a warning to pilots that dangerous weather is in the region. (BANG of hail)
The storm suddenly gets much worse. Hail the size of baseball hammers the DC-9, breaking the planes windshield. The plane loses all electrical power. After 36 seconds in the dark power returns. The instruments come alive and radio begins working again.
1) What was the destination of Flight 242? How many passengers were on board?
It was Atlanta, Georgia. 81 passenger.
2) What aircraft type performed the flight? In what way was its design special?
DC-9. It was designed for take-off on shorter runways and fly frequent short flights. Both of its engines are mounted to the rear fuselage rather than wings.
3) What was analyzed by the crew before takeoff? What information must any flight crew receive and analyze before the flight?
They were analyzing weather report for the airports along their route. Each flight crew is supposed to be provided with actual and consistent meteorological information in a form of text reports and forecasts (METAR, TAF), and weather charts.
4) Were the weather conditions adverse at the beginning of the flight? What was the weather like?
The DC-9 took-off into a hard rain. The weather was unstable that day, It was smooth at the beginning, but then started worsening.
5) What weather phenomena were tracked by meteorologists in the area?
Tornados that are violently rotating columns of air that is in contact with both the surface of the earth and a cumulonimbus cloud.
6) According to the film, what weather conditions are typical for the southern part of the USA?
The weather there can be very hazardous. High humidity, high temperature, convective heating are all prescription for thunderstorms that are associated with heavy rain, hail, icing conditions and extreme wind.
7) Did the pilots receive the weather update? What weather conditions did their weather radar allow to detect?
Controller warned pilots about increasing of precipitation intensity on their route. Most aircraft were equipped with bendix weather radar. It painted regions with bad weather in bright color.
8) How did the crew intend to proceed on their route? Did they intend to divert the flight?
The pilots spotted dark area on the radar and planned to navigate through it.
9) What is a SIGMET? What were the pilots of Flight 242 alerted about?
SIGMET stands for significant meteorological information. It is a warning to pilots about dangerous weather in a particular region.
10) What problems did the flight encounter after getting into the storm activity?
The plane lost all electrical power and its windshield was cracked.
11) Was the electrical failure total? How did the situation improve?
After 36 seconds in the dark power returned. The instruments come alive and radio begun working again.
12) What adverse weather conditions that can affect flight safety do you know?
They are wind-shear, icing conditions, heavy precipitation, turbulence and some others.+
What problems can they lead to?
Wind-shear has a significant effect during take-off and landing because it affects aircraft airspeed and it can lead to stall and impact into terrain.
Ice accretion on airframe increases drug, weight and stall speed.
Heavy precipitation can cause aircraft damage and jet engine to flame out. Also it makes runway slippery.
What makes weather such a significant factor in aviation?
It affects flight safety.
What are the typical weather conditions in your region?
I am from SPb and this region is famous for its rainy weather. We have a joke that in SPb there are only 30 sunny days in a year, and it is not so far from the truth. Had the city been founded further to the south the weather would have been much better.
How do they influence flying?
Concerning aviation such weather contributes to low visibility, icing and runway contamination.