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Last updated: 12 November 2019
Status:Definitief
Datum:zondag 28 december 1997
Tijd:23:10 JST
Type:Silhouette image of generic B741 model; specific model in this crash may look slightly different
Boeing 747-122
Luchtvaartmaatschappij:United Airlines
Registratie: N4723U
Constructienummer: 19882/175
Bouwjaar: 1971-12-17 (26 years )
Motoren: 4 Pratt & Whitney JT9D-7A
Bemanning:slachtoffers: 0 / inzittenden: 19
Passagiers:slachtoffers: 1 / inzittenden: 374
Totaal:slachtoffers: 1 / inzittenden: 393
Schade: Afgeschreven
Gevolgen: Written off (damaged beyond repair)
Plaats:1530 km (956.3 mijl) ESE of Tokyo (   Grote Oceaan)
Fase: Kruisvlucht (ENR)
Soort vlucht:Internationale lijnvlucht
Vliegveld van vertrek:Tokyo-Narita Airport (NRT/RJAA), Japan
Vliegveld van aankomst:Honolulu International Airport, HI (HNL/PHNL), Verenigde Staten
Vluchtnummer:UA826
Beschrijving:
The takeoff, departure, and climb out of Tokyo-Narita Airport were uneventful. Approximately one hour and forty minutes into the flight the airplane encountered "wave action" and the captain turned the seatbelt sign on as a precaution. The captain also radioed Northwest flight 90, ahead of him, requesting a ride report. NW 90 reported that the ride was smooth with an occasional ripple of light turbulence at their altitude. The first turbulence encounter happened no more than one to two minutes later. The aircraft encountered severe turbulence about 2 minutes after the "wave activity." Seconds later, the flight experienced another turbulence episode. During the turbulence, the captain made a PA announcement for the flight attendants to sit down and then he made a PA announcement to the passengers telling them not to be alarmed. The captain ordered the first officer to reduce speed, and he complied by reducing the indicated airspeed to approximately 330-340 knots IAS. During the encounters, the Boeing moved upwards at 1,8g, sideways (0,1g lateral) and down again 6 seconds later (-0,8g). Before and after the turbulence encounters, the captain saw a band of clouds with no lightning to the right and below the aircraft, but he did not see any lightning or clouds along the route of flight. At the point at which the captain requested permission from ATC to climb to FL330, he asked the purser to provide him with information about the conditions in the cabin following the turbulence. The purser informed the captain that a flight attendant was in the aisle, the cabin was "a mess", and there were several injuries. The captain then asked the purser to see if a doctor was on board. Two doctors were found who asked for and were given the airplane's medical kit, oxygen bottles and first aid kits. One doctor stayed with the flight attendants in the back of the cabin who were performing CPR on an unconscious passenger. The other doctor assisted the flight attendants who were providing first aid to other passengers. Upon making an assessment of the injuries and determining that the aircraft had not sustained structural damage, the captain made the decision to return to Narita for medical assistance.
The Boeing 747 was declared damaged beyond repair because the plane would have been taken out of service early 1998 anyway.

Probable Cause:

PROBABLE CAUSE: "The pilot-in-command's inadvertent flight into adverse weather conditions, and the difficulty of obtaining adequate weather forecasts of over-ocean turbulence. Factors contributing to the accident include the presence of clear air turbulence, and the failure of the flight attendant to issue a safety advisory."

Bronnen:
» SKYbrary 
» Aviation Week & Space Technology 12.01.1998 (389)
» NTSB id. DCA98MA015


Veiligheidsmaatregelen
Following the accident, United Airlines issued Flight Safety Information Bulletin 98-1, titled "Turbulence Encounter and Passenger Fatality." This bulletin described the circumstances of the accident, commended the crew for conscientiously discharging its duties and also reiterated the importance of effective communication between pilots and flight attendants. Shortly after the accident, United Airlines took measures to reinforce its policy of encouraging passengers to wear seat belts whenever seated and regardless of whether the seat belt sign is illuminated.

Foto's

photo of Boeing-747-122-N4723U
accident date: 28-12-1997
type: Boeing 747-122
registration: N4723U
 

Kaart
Deze kaart geeft het vliegveld van vetrek weer en de geplande bestemming van de vlucht. De lijn tussen de vliegvelden geeft niet de exacte vliegroute weer.
De afstand tussen Tokyo-Narita Airport en Honolulu International Airport, HI bedraagt 6095 km (3809 miles).
Accident location: Global; accuracy within tens or hundreds of kilometers.

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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Boeing 747

  • 1551+ built
  • 29e ongeval
  • 19e dodelijk ongeval
  • 19e zwaarste ongeval (toen het plaatsvond)
  • 28e zwaarste ongeval (op dit moment)
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