Narrative:
The flight crew received flight release documents containing weather information from airline dispatch that was incomplete and did not contain pertinent Convective SIGMETs and a tornado watch bulletin. However, the flight crew stated that before departure from Atlanta (ATL), they looked at a computerized weather display and observed a line of adverse weather conditions along their intended route of flight. During initial climb after takeoff, the flight crew noticed that they were approaching a line of thunderstorms. The captain initially planned to fly around this line but noticed a 10-mile gap in the line that was depicted on the airplane's on-board weather radar display. The captain decided to fly through the gap, which he could also see when he looked outside of the airplane. Radar and weather data indicate that the airplane penetrated an extreme weather echo (VIP level 6) that likely contained a severe thunderstorm, hail, and severe to extreme turbulence. The thunderstorm top was above 45,000 feet. Neither the flight attendants nor the passengers received an adequate or timely briefing to remain seated and to prepare for the possibility of turbulence. The aft flight attendant and a passenger were seriously injured during the turbulence encounter. Hail shattered the front windshield and damaged the pitot system, radome, wings, tail, and engines. The flight crew successfully performed an emergency landing at Chattanooga-Lovell Field, TN (CHA). The investigation revealed that the captain had been involved in two other air carrier incidents involving adverse weather conditions. It also revealed that the airline lacked adequate training and guidance regarding hazardous weather interpretation and avoidance, as well as adequate procedures to notify flight attendants about potential turbulence. According to FAA guidance, flight crews should avoid intense or extreme level radar echoes by at least 20 miles. This guidance also instructs pilots that such echoes should be separated by at least 40 miles before flight is attempted between the echoes.
PROBABLE CAUSE: "The failure of the flight crew to maintain adequate separation from hazardous meteorological conditions. Factors contributing to the accident were: (1) the failure of AirTran Airlines to provide adequate crewmember training and guidance regarding hazardous weather encounters; (2) the failure of the flight crew to provide an adequate and timely briefing to the flight attendants regarding turbulence; and (3) the presence of hail and turbulence."
Forced landing on runway
| Status: | Accident investigation report completed and information captured |
| Date: | Thursday 7 May 1998 |
| Time: | 19:20 |
| Type: |  McDonnell Douglas DC-9-32 |
| Operator: | AirTran Airways |
| Registration: | N948VV |
| MSN: | 47559/672 |
| First flight: | 1972 |
| Crew: | Fatalities: 0 / Occupants: 6 |
| Passengers: | Fatalities: 0 / Occupants: 81 |
| Total: | Fatalities: 0 / Occupants: 87 |
| Aircraft damage: | Substantial |
| Aircraft fate: | Repaired |
| Location: | near Calhoun, GA ( United States of America)
|
| Phase: | En route (ENR) |
| Nature: | Domestic Scheduled Passenger |
| Departure airport: | Atlanta-William B. Hartsfield International Airport, GA (ATL/KATL), United States of America |
| Chicago-Midway Airport, IL (MDW/KMDW), United States of America | |
| Flightnumber: | 426 |
The flight crew received flight release documents containing weather information from airline dispatch that was incomplete and did not contain pertinent Convective SIGMETs and a tornado watch bulletin. However, the flight crew stated that before departure from Atlanta (ATL), they looked at a computerized weather display and observed a line of adverse weather conditions along their intended route of flight. During initial climb after takeoff, the flight crew noticed that they were approaching a line of thunderstorms. The captain initially planned to fly around this line but noticed a 10-mile gap in the line that was depicted on the airplane's on-board weather radar display. The captain decided to fly through the gap, which he could also see when he looked outside of the airplane. Radar and weather data indicate that the airplane penetrated an extreme weather echo (VIP level 6) that likely contained a severe thunderstorm, hail, and severe to extreme turbulence. The thunderstorm top was above 45,000 feet. Neither the flight attendants nor the passengers received an adequate or timely briefing to remain seated and to prepare for the possibility of turbulence. The aft flight attendant and a passenger were seriously injured during the turbulence encounter. Hail shattered the front windshield and damaged the pitot system, radome, wings, tail, and engines. The flight crew successfully performed an emergency landing at Chattanooga-Lovell Field, TN (CHA). The investigation revealed that the captain had been involved in two other air carrier incidents involving adverse weather conditions. It also revealed that the airline lacked adequate training and guidance regarding hazardous weather interpretation and avoidance, as well as adequate procedures to notify flight attendants about potential turbulence. According to FAA guidance, flight crews should avoid intense or extreme level radar echoes by at least 20 miles. This guidance also instructs pilots that such echoes should be separated by at least 40 miles before flight is attempted between the echoes.
Probable Cause:
PROBABLE CAUSE: "The failure of the flight crew to maintain adequate separation from hazardous meteorological conditions. Factors contributing to the accident were: (1) the failure of AirTran Airlines to provide adequate crewmember training and guidance regarding hazardous weather encounters; (2) the failure of the flight crew to provide an adequate and timely briefing to the flight attendants regarding turbulence; and (3) the presence of hail and turbulence."
Accident investigation:
 |
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Classification:
ThunderstormForced landing on runway
Sources:
» NTSBPhotos
Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Atlanta-William B. Hartsfield International Airport, GA to Chicago-Midway Airport, IL as the crow flies is 945 km (591 miles).
Distance from Atlanta-William B. Hartsfield International Airport, GA to Chicago-Midway Airport, IL as the crow flies is 945 km (591 miles).
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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