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Last updated: 28 September 2021
Statuts:Enquête Officielle
Date:jeudi 28 juillet 2011
Heure:04:10
Type/Sous-type:Silhouette image of generic B744 model; specific model in this crash may look slightly different
Boeing 747-48EF
Compagnie:Asiana Airlines
Immatriculation: HL7604
Numéro de série: 29907/1370
Année de Fabrication: 2006-02-15 (5 years 5 months)
Heures de vol:28752
Cycles:4799
Moteurs: 4 General Electric CF6-80C2B1F
Equipage:victimes: 2 / à bord: 2
Passagers:victimes: 0 / à bord: 0
Total:victimes: 2 / à bord: 2
Dégats de l'appareil: Détruit
Conséquences: Written off (damaged beyond repair)
Lieu de l'accident:130 km (81.3 milles) W de Jeju, South Korea [East China Sea] (   Océan Pacifique)
Phase de vol: En vol (ENR)
Nature:Cargo
Aéroport de départ:Seoul-Incheon International Airport (ICN/RKSI), Corée du Sud
Aéroport de destination:Shanghai-Pudong International Airport (PVG/ZSPD), Chine
Numéro de vol:OZ991
Détails:
A Boeing 747-400F cargo plane, HL7604, was destroyed when it crashed into the sea off Jeju, South Korea. Both pilots were killed in the accident.
Asiana Airlines flight 991 departed Seoul-Incheon International Airport (ICN) at 03:05 on a cargo flight to Shanghai-Pudong International Airport (PVG), China.
At 03:51, at FL340, the copilot made initial contact with Shanghai Area Control Center (ACC).
Three minutes later the copilot radioed, "Shanghai control, Shanghai control, AAR991 request emergency descent, emergency, declare emergency due to fire main deck. Request descent, and descent to one-zero thousand." This request was approved.
In subsequent communication the copilot stated that they wanted to divert back to Jeju with a descent to FL100.
At 04:00, Shanghai Control instructed AAR991 to contact Incheon ACC for a radar vector to Jeju, however, AAR991 stated that it was unable to contact on that frequency. The radar data of Incheon ACC shows that at 04:01, AAR991 was flying at 8,200 ft at a ground speed of 404 kt on a heading of 033°, and after this, AAR991's altitude, ground speed, and heading changed inconsistently.
At 04:02 contact was transferred to Fukuoka ACC. The flight then radioed: "Fukuoka AAR991 mayday mayday mayday, we have cargo fire, request direct to Jeju please." With Fukuoka ACC failing to respond, the crew contacted Shanghai ACC again.
Korean Air flight KE886 was used to relay radar vectors and descent instructions from Incheon ACC. The captain then reported rudder control problems to KE886. Control problems appeared to worsen as the captain radioed: "Rudder control... flight control, all are not working." at 04:09.
Meanwhile the first officer managed to change frequencies to Jeju ACC, stating: "We have heavy vibration on the airplane, may need to make an emergency landing, emergency ditching.". Last contact was at 04:10 when the first officer radioed: "Altitude control is not available due to heavy vibration, going to ditch... ah." According to radar data the altitude at that time was about 10.000 feet.
The airplane then entered a high speed descent and struck the surface of the sea and broke up. The wreckage sank to a depth of about 85 metres.

The plane carried 58 tonnes of cargo, including 0.4 tonnes of potentially risky materials such as lithium batteries, paint, amino acid solution and synthetic resin.

Probable Cause:

Causes:
The Aviation and Railway Accident Investigation Board (ARAIB) determines the cause of this accident as follows:
A fire developed on or near the pallets containing dangerous goods but no physical evidence of the cause of the fire was found. The fire rapidly escalated into a large uncontained fire, and this caused some portions of the fuselage to separate from the aircraft in midair, thereby resulting in the crash.

Contributing Factors
1. Flammable materials like photo-resist (Class 3) were loaded in position ML, and flammable materials like paint, photo-resist, corrosive liquid, and lithium-ion batteries (Class 9) were loaded on one pallet in position PR.
2. It was difficult to contain a large scale of fire only by the fire suppression system of a Class E cargo compartment that was not equipped with an active fire suppression system.

Accident investigation:
cover
Investigating agency: ARAIB
Status: Investigation completed
Duration: 4 years
Accident number: ARAIB/AAR1105
Download report: Final report

Sources:
» Korean Ministry of Transport
» Flightglobal
» SKYbrary 


Opérations de secours

ARAIB issued 20 Safety Recommendations
NTSB issued 5 Safety Recommendations

Show all...

Photos

photo of Boeing-747-48EF-HL7604
Altitude and speed before the crash
photo of Boeing-747-48EF-HL7604
accident date: 28-07-2011
type: Boeing 747-48EF
registration: HL7604
photo of Boeing-747-48EF-HL7604
accident date: 28-07-2011
type: Boeing 747-48EF
registration: HL7604
 

Plan
Ce plan montre l'aéroport de départ ainsi que la supposée destination du vol. La ligne fixe reliant les deux aéroports n'est pas le plan de vol exact.
La distance entre Seoul-Incheon International Airport et Shanghai-Pudong International Airport est de 817 km (511 miles).
Accident location: Exact; as reported in the official accident report.

Les informations ci-dessus ne représentent pas l'opinion de la 'Flight Safety Foundation' ou de 'Aviation Safety Network' sur les causes de l'accident. Ces informations prélimimaires sont basées sur les faits tel qu'ils sont connus à ce jour.
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