Incident Overview
Description
Northwest Airlines Flight 22, a Boeing 747-151, N606US, encountered unforecast severe turbulence at cruise altitude approximately 50 minutes after departure from Tokyo, Japan, while en route to Honolulu, Hawaii. There were 146 passengers and a crew of 14 aboard the aircraft. Seven of the passengers received minor injuries, and two received serious injuries. Five cabin attendants received minor injuries. The aircraft was in level flight at 33,000 feet in smooth air when it encountered turbulence which ranged in intensity from light to severe for approximately 55 seconds. The “Fasten Seatbelt” sign was illuminated immediately when the turbulence was encountered; however, during the period of the turbulence, some of the passengers and flight attendants were thrown about in the cabin and sustained injuries. The aircraft was undamaged and continued on to Honolulu where the injured persons were deplaned and hospitalized. The National Transportation Safety Board determines that the probable cause of this accident was the entry of the aircraft into an area of unforecast and unexpected severe clear air turbulence when some occupants did not have their seatbelts fastened.
Primary Cause
Unforeseen and unexpected severe clear air turbulence.Unforeseen and unexpected severe clear air turbulence.Share on:
