United Airlines Flight 826

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United Airlines Flight 826
Boeing 747-122, United Airlines AN1094854.jpg

The affected machine in 1992
Accident summary
Accident type Clear Air Turbulence
place Pacific Ocean , 1,530 kilometers east-southeast of Tokyo , JapanJapanJapan 
date December 28, 1997
Fatalities 1
Survivors 392
Injured 102
Aircraft
Aircraft type United StatesUnited States Boeing 747-122
operator United StatesUnited States United Airlines
Mark N4723U
Departure airport Tokyo Narita Airport , Japan
JapanJapan 
Destination airport Honolulu Airport , Hawaii , United StatesUnited StatesUnited States 
Passengers 374
crew 19th
Lists of aviation accidents

On the United Airlines Flight 826 (Flight number: UA826 ) a serious flight accident occurred on 28 December 1997, which as a Boeing 747-122 United Airlines on a trans-Pacific intercontinental flight from Tokyo to Honolulu in a clear air turbulence flew. A 32-year-old Japanese passenger died in the incident and 102 people on board the plane were injured.

machine

The aircraft involved in the accident was a Boeing 747-122, which was 26 years old at the time of the accident. The machine was assembled at the Boeing plant in Everett , Washington state , and made its maiden flight on December 17, 1971. The aircraft had the factory number 19882, it was the 175th Boeing 747 from ongoing production. On January 6, 1972, the aircraft was delivered new to United Airlines , where it has since been in service with the aircraft registration number N4723U . The four-engine wide - body aircraft was equipped with four Pratt & Whitney JT9D-7 engines.

Passengers and crew

There were 374 passengers and a 19-person crew on board, consisting of a three-person cockpit crew and 16 flight attendants. The cockpit crew consisted of a flight captain, a first officer and a second officer. The captain had 15,000 hours of flight experience, including 1,100 hours as the captain of the Boeing 747. The first officer had 10,000 hours of flight experience, of which he had completed around 1,500 hours in the Boeing 747. The second officer had 3,500 hours of flight experience as a pilot and 850 hours of flight experience in the position of second officer, all of which he had completed in the cockpit of the Boing 747.

Course of the flight and course of the accident

The plane took off on December 28, 1997 at 8:30 p.m. local time from Narita Airport . Less than half an hour later, it reached its cruising altitude of 9,448 meters. The master chose the only approved route at a time when no severe turbulence or thunderstorms were predicted.

At cruising altitude the flight initially encountered some turbulence, whereupon the captain switched on the seat belt sign. A quarter of an hour later the turbulence subsided and the seat belt sign was switched off. At the time, the captain announced to passengers that turbulence was still possible and that the seat belts should be worn while seated. A flight attendant translated the announcement into Japanese.

About an hour later, when the machine was flying in calm conditions, the seat belt sign was turned on again without notice. After about two minutes of light turbulence, the 747 suddenly dropped slightly and then shot up and down again at such a rate that a purser clinging to a solid work surface was hanging upside down with his feet in the air while he was always hanging still clinging to the countertop. The plane rose steeply again before falling sharply again. After another slight ascent, the machine returned to normal flight operations.

In the incident, a 32-year-old Japanese passenger with her seatbelt loosened was found lying in the aisle, unconscious and bleeding profusely. Despite quick attempts at resuscitation by injured flight attendants and a doctor present as a passenger, she had to be pronounced dead.

Three flight attendants and 15 passengers had injuries to their spine and neck. Another 87 passengers had bruises , sprains and other minor injuries.

Although Henderson Field on Midway Atoll would have been the closest airport, the captain decided to return to Tokyo after discovering that the plane was still airworthy and assuming that medical care for the injured in Tokyo would be better ensured would. Three hours later the plane landed safely at Narita Airport.

Accident investigation

The National Transportation Safety Board (NTSB) undertook the investigation after the accident. The evaluation of the flight data recorder showed that the sensors initially recorded a maximum normal acceleration of 1.814 g on the first steep ascent of the machine. Then the data showed that the aircraft had rolled 18 ° to the side and was falling with an acceleration force of −0.824 g.

The NTSB investigation found a problem that could have prevented death and many injuries. Nobody could remember hearing the typical seat belt buckle when the seat belt light came on about two minutes before the turbulence incident. In addition, it was not announced in either English or Japanese that the seat belts should be fastened.

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