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United Airlines Flight 826

United Airlines Flight 826
The aircraft involved in the accident, N4723U, at London Heathrow Airport in 1992
Accident summary
Date December 28, 1997
Summary Clear-air turbulence
Site Pacific Ocean
Passengers 374
Crew 19
Injuries (non-fatal) 18
Fatalities 1 (from injuries)
Survivors 392
Aircraft type Boeing 747-122
Operator United Airlines
Registration N4723U[1]
Flight origin Tokyo-Narita International Airport (NRT/RJAA)
Destination Honolulu International Airport, HI (HNL/PHNL)

On December 28, 1997, United Airlines Flight 826 was operated by a Boeing 747-100 flying from New Tokyo Airport (Changed name to a Narita Airport in 2004), Japan to Honolulu International Airport, Hawaii. Two hours into the flight, at an altitude of 31,000 feet (9,400 m), the plane received reports of severe clear-air turbulence in the area and the seat belt sign was turned on. Moments later, the aircraft suddenly dropped around 100 feet (30 m), seriously injuring 15 passengers and 3 crew members,[2] The plane turned around and landed safely back in Tokyo, but one passenger, a 32-year-old Japanese woman, later died of her injuries.[2][3]


  • Flight details 1
  • NTSB investigation and aftermath 2
  • Footnotes 3
  • External links 4

Flight details

Flight 826 departed Tokyo's Narita airport on December 28, 1997 at 20:30 local time. It reached a cruising altitude of 31,000 feet just under a half-hour later. The flight was originally planned to cruise at 35,000 feet, but air traffic control (ATC) only cleared to cruise at the lower altitude due to air traffic. The captain chose the only authorized route at the time in which severe turbulence or thunderstorms were not forecast to occur. [4]

At cruising altitude, the flight initially encountered enough turbulence for the captain to turn on the fasten seatbelt sign. Fifteen minutes later, the turbulence subsided and the fasten seatbelt sign was switched off. At the time the captain announced to the passengers that turbulence was still a possibility and that the seat belts should be fastened when seated. A flight attendant made a Japanese announcement that was similar. [4]

About an hour later after calm conditions, the fasten seat belt sign came on again without any announcement. After about two minutes of not very strong turbulence, suddenly the 747 dropped slightly then shot back up and then back down at such a velocity that a purser, who was hanging on to a fixed countertop, found himself hanging upside down holding the countertop with his feet in the air. The airplane then pitched up and steeply climbed before heavily falling again, this occurring when the right wing dropped sharply. After another moderate climb, the flight returned to normal.[4]

After the incident, a Japanese woman who had her belt unfastened was found lying unconscious and bleeding heavily in the aisle. Despite quick resuscitation efforts by injured flight attendants and a passenger doctor, she was soon pronounced dead.[4]

Fifteen passengers and three flight attendants had spine and neck fractures. Another 161 other passengers had bruises, sprains and other minor injuries. While Midway Atoll was the closest airport, the captain opted to return to Tokyo after assessing the aircraft was still flightworthy and Tokyo had medical facilities judged better to handle the injuries. [4]

Three hours later, the aircraft landed safely at Narita airport.

NTSB investigation and aftermath

The flight data recorder, as analyzed by the National Transportation Safety Board (NTSB), found that the sensors had initially recorded a peak normal acceleration of 1.814G in the first sharp ascent. Then the date showed that the aircraft had an out of control roll by 18° and then plunged to an extreme negative G of -0.824g.

The NTSB investigation found a potential issue that could’ve prevented the death and many injuries. Nobody could remember hearing the typical fasten seat belt chime when the fasten seat belt light came on about two minutes before the turbulence event and no announcements of the fasten seat belt light being on was made in either English or Japanese. [4][5]

United Airlines had previously intended to sell the aging aircraft to a salvage company in early 1998. After this incident, the airline opted to retire the aircraft soon afterwards with Flight 826 being the last revenue flight. [4][5]


  1. ^ "FAA Registry". Federal Aviation Administration. 
  2. ^ a b "Aircraft Accident Investigation United Airlines flight 826, Pacific Ocean". Retrieved 8 October 2015. 
  3. ^ "NTSB examines data recorder from turbulent United flight." CNN. December 30, 1997. Retrieved on December 23, 2014.
  4. ^ a b c d e f g Sóbester, Andras (2011). Stratospheric Flight: Aeronautics at the Limit.  
  5. ^ a b "NTSB Identification: DCA98MA015".  

External links

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