Air France Flight 004, a Boeing 707-328B entered an area of light turbulence near O’Neill, Nebraska, USA. About 3 to 5 minutes later, the flight encountered moderate to severe turbulence, which lasted about 4 1/2 minutes. During the turbulence, 2 passengers were injured seriously and 11 were injured slightly. Two flight attendants were injured, one seriously. The captain went to the cabin to see the injured passengers and discussed the injuries with a passenger who was a doctor. The captain decided to continue to Paris, France, and landed the aircraft at Orly Airport, Paris, almost 7 hours after the in-flight turbulence encounter. The National Transportation Safety Board determines that the probable cause of the accident was the operation of the aircraft in an area of very strong thunderstorm activity which should have been easily. detectable and which resulted in serious injuries to passengers because of the failure of the captain to warn the passengers and to turn on the “fasten seatbelt” sign.