Crash-aerien 22 DEC 1999 d'un Boeing 747-2B5F (SCD) HL7451 - Great Hallingbury
ASN logo
Statuts:Accident investigation report completed and information captured
Date:mercredi 22 dcembre 1999
Type/Sous-type:Silhouette image of generic B742 model; specific model in this crash may look slightly different
Boeing 747-2B5F (SCD)
Compagnie:Korean Air
Immatriculation: HL7451
Numéro de série: 22480/448
Année de Fabrication: 1980-04-30 (19 years 8 months)
Heures de vol:83011
Moteurs: 4 Pratt & Whitney JT9D-7Q
Equipage:victimes: 4 / à bord: 4
Passagers:victimes: 0 / à bord: 0
Total:victimes: 4 / à bord: 4
Dégats de l'appareil: Détruit
Conséquences: Written off (damaged beyond repair)
Lieu de l'accident:près de Great Hallingbury (   Royaume Uni)
Phase de vol: En montée initiale (ICL)
Aéroport de départ:London-Stansted Airport (STN/EGSS), Royaume Uni
Aéroport de destination:Milano-Malpensa Airport (MXP/LIMC), Italie
Numéro de vol:KE8509
Boeing 747 HL-7451 arrived at Stansted at 15:05 after a flight from Tashkent. Prior to leaving the aircraft, the flight engineer made an entry in the Technical Log stating "Captain's ADI [Attitude Director Indicator] unreliable in roll' he also verbally passed the details to the operator's ground engineer who met the aircraft on arrival. During turnover repair works on the ADI were carried out. Some cargo was offloaded and other cargo loaded for the flight to Milan-Malpensa (takeoff weight was 548,352 lb including 68,300 lb of fuel) and a new crew boarded the aircraft. After a delay of an hour, because ATC had not received the flight plan, Flight 8509 was cleared to depart Stand Alpha 6 and taxi to runway 23 holding point at 18:25. Subsequently, at 18:36 KAL 8509 was cleared to takeoff with a reported surface wind of 190deg/18 kt. The Dover 6R Standard Instrument Departure called for a climb ahead to 1.5 miles DME, then a left turn onto the 158 inbound radial to the Detling VOR. Climbing through 900 feet, the ADI 'Comparator' buzzer sounded three times. Shortly afterwards, the warning sounded a further two times, coincident with the captain expressing concerns over his DME indication. Climbing through 1400 feet, ATC instructed the crew to contact 'London Control'. And as the captain initiated the procedure turn to the left, the 'Comparator' warning sounded again some 9 times. The maximum altitude reached was 2,532 feet amsl. The aircraft then banked left progressively and entered a descent until it struck the ground in a approx. 40deg nose down pitch and 90deg bank to the left; the speed was high in the region of 250 to 300 kt.

Probable Cause:

The following causal factors were identified:
1 The pilots did not respond appropriately to the comparator warnings during the climb after takeoff from Stansted despite prompts from the flight engineer.
2 The commander, as the handling pilot, maintained a left roll control input, rolling the aircraft to approximately 90° of left bank and there was no control input to correct the pitch attitude throughout the turn.
3 The first officer either did not monitor the aircraft attitude during the climbing turn or, having done so, did not alert the commander to the extreme unsafe attitude that developed.
4 The maintenance activity at Stansted was misdirected, despite the fault having been correctly reported using the Fault Reporting Manual. Consequently the aircraft was presented for service with the same fault experienced on the previous sector; the No 1 INU roll signal driving the captain's ADI was erroneous.
5 The agreement for local engineering support of the Operator's engineering personnel, was unclear on the division of responsibility, resulting in erroneous defect identification, and mis-directed maintenance action.

Accident investigation:

Investigating agency: AAIB
Status: Investigation completed
Duration: 3 years and 5 months
Accident number: AAIB AAR 3/03
Download report: Final report

» SKYbrary 

Opérations de secours
The following safety recommendations were made during the course of the investigation. It is recommended that:

Safety Recommendation No 2003-62: Korean Air continue to update their training and Flight Quality Assurance programmes, to accommodate Crew Resource Management evolution and industry developments, to address issues specific to their operational environment and ensure adaptation of imported training material to accommodate the Korean culture.

Safety Recommendation No 2003-63: Korean Air continue to review its policy and procedures for maintenance support at international destinations with a view to deploying sufficient of its own full-time engineers at the outstation or delegating the entire task to another operator or third-party maintenance organisation locally-based at the destination (Full Technical Handling). If neither of these approaches is practicable then the support arrangements must be detailed and of such clarity as to preclude confusion.

Safety Recommendation No 2003-64: Korean Air review its policy and procedures to ensure that a copy of the relevant pages of the Technical Log and any other transit certification documents are left on the ground at the point of departure.

Safety Recommendation No 2003-65: ICAO Technical Instructions Part 7, chapter 4.6.1 be amended to, 'The operator of an aircraft carrying dangerous goods which is involved in an aircraft accident must, as soon as possible, inform the appropriate Authority in the State in which the aircraft accident occurred of the dangerous goods carried together with their proper shipping names, class and subsidiary risks for which labels are required, the compatibility group for Class 1 and the quantity and location on board the aircraft'.

Safety Recommendation No 2003-66: ICAO consider an initiative to review the current methods of tracking air cargo and further consider improved systems, utilising electronic data storage and transmission, with a view to providing timely information on the cargo carried by any aircraft involved in an accident.

Safety Recommendation No 2003-67: The ICAO Hazards at Accident Sites Study Group is supported and resourced to enable it to meet its target date for delivery of the necessary data and risk management advice.


photo of Boeing-747-2B5F-HL7451
accident date: 22-12-1999
type: Boeing 747-2B5F (SCD)
registration: HL7451
photo of Boeing-747-2B5F-HL7451
accident date: 22-12-1999
type: Boeing 747-2B5F (SCD)
registration: HL7451
photo of Boeing-747-2B5F-HL7451
accident date: 22-12-1999
type: Boeing 747-2B5F (SCD)
registration: HL7451

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 London-Stansted Airport et Milano-Malpensa Airport est de 925 km (578 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.
languages: languages


Boeing 747

  • 1551+ built
  • 33ème loss
  • 20ème accident fatal
  • le accident 18ème le plus grave (à ce moment là)
  • le accident 23ème le plus grave (en ce moment)
» safety profile

The Aviation Safety Network is an exclusive service provided by:
Quick Links:

CONNECT WITH US: FSF Facebook FSF Twitter FSF Youtube FSF LinkedIn FSF Instagram

©2023 Flight Safety Foundation

1920 Ballenger Av., 4th Fl.
Alexandria, Virginia 22314