Korean Air Flight 8509
| Korean Air Flight 8509 | |
|---|---|
 The plane in 1992 at Paris-Charles-de-Gaulle Airport |
|
| Accident summary | |
| Accident type | Loss of control after instrument failure |
| place | Great Hallingbury |
| date | December 22, 1999 |
| Fatalities | 4th |
| Aircraft | |
| Aircraft type | Boeing 747-2B5F |
| operator | Korean Airlines |
| Mark | HL7451 |
| Departure airport |
London Stansted Airport , United Kingdom
|
| Destination airport |
Milan Malpensa Airport , Italy
|
| Passengers | 0 |
| crew | 4th |
| Lists of aviation accidents | |
On December 22, 1999, a Boeing 747-200F freighter on Korean Air flight 8509 ( flight number : KE8509 or KAL8509) had an accident shortly after take-off from London-Stansted Airport as a result of an instrument failure . The four crew members were killed in the accident.
background
The Boeing 747 ( registration number : HL7451) of Korean Air arrived at 3:05 p.m. with another crew from Seoul ( South Korea ) via Tashkent ( Uzbekistan ) in London-Stansted. Shortly after the start in Tashkent the captain had the climb initiated a curve, and have found that in his artificial horizon , although the (Attitude Direction Indicator, ADI) pitch of the aircraft is displayed correctly, however, the device no bank indicated. Because the flight took place during the day and there were therefore visual reference points outside the cockpit, the captain recognized the instrument error immediately. The second artificial horizon at the co-pilot's position and the third, centrally located replacement instrument indicated the flight attitude correctly. The copilot took control of the machine and continued the climb. At cruising altitude , the master changed the setting of his ADI, whereby this artificial horizon was supplied with information via another output of the inertial navigation system (INS). The attitude was then displayed correctly in the captain's ADI, but the third horizon now provided an incorrect display. The pilots recognized that the source of the error was in the inertial navigation system and documented this in the aircraft's logbook. They also filled out a corresponding repair order and verbally informed the local Korean Air station manager about the problem after landing in London-Stansted .
The station manager hired an engineer from the airline to repair the ADI, without indicating that the actual fault could be in the inertial navigation system. Likewise, the repair form completed by the crew was not forwarded to the engineer. The supposedly defective artificial horizon was expanded with the help of a third-party mechanic and its connections checked. The engineer found that a plug was only loosely in the device. Assuming that the error had been found and corrected, the artificial horizon was built in again. A subsequent function test gave no indication of an ADI disorder. The inertial navigation system was neither checked nor replaced its defective component.
While the aircraft was being loaded for the onward flight to Milan-Malpensa , a new crew came into service. She was not informed of the previous repair.
the accident
The aircraft was ready to take off at 17:27. However, the start was delayed by over an hour because the station manager had failed to submit the flight plan . At 18:36, the aircraft in the dark of the raised rail 23.. The master performed the climb manually, while the co-pilot, as “ pilot not flying ”, was responsible for radio communications and monitoring the instruments. The departure procedure provided for turning left at a distance of around 2.8 kilometers (1.5 NM ) from the DME of the airport onto the 338 ° radial of the Detling radio beacon (BEFORE Detling). During the climb, the cockpit voice recorder recorded several warning tones from the “ADI Comparator”, which indicated a different representation of the flight situation in the three artificial horizons. The pilots did not respond to the acoustic warnings.
When the aircraft passed an altitude of around 425 meters (1,400 feet ), the co-pilot was requested by the air traffic controller in the tower to contact departure control. At the same time, the master initiated the left turn by around 70 degrees in the direction of the VOR Detling. When the machine turned, its bank angle was not displayed in the master's ADI. Although the flight engineer , who observed the attitude in the third artificial horizon, called out to bank, the master kept the deflection of the aileron unchanged, as a result of which the roll angle increased continuously. When the angle finally reached 90 degrees, the machine rolled over the left wing at an altitude of 585 meters (1920 feet) and went into an uncontrolled descent. The aircraft impacted at a speed of about 463 to 555 km / h (250 to 300 kts ) in an unchanged left bank angle and with a pitch angle (negative pitch) of 40 degrees just under two kilometers south of the airport on the edge of the forest in Great Hallingbury .
Cause of accident
According to the investigative commission, the accident was caused by inadequate crew resource management . There was hardly any communication between the crew members, so that the instrument error was not recognized by them.
Immediately after the captain had initiated the left turn, the flight engineer called out to bank for the first time and also gave an imprecise indication of a possible malfunction ( “bank is not working” ) without the captain responding or the copilot. At the same time, the "ADI Comparator" gave nine more warning tones. Despite the warning sounds and although no inclination was indicated in his ADI, the master kept the rudder deflection. He completely neglected to request information from the co-pilot about the display of the flight situation on his ADI. Likewise, the master did not use the third artificial horizon in the middle, on which the flight engineer observed the flight situation in order to check the display of his ADI.
After the aircraft had further inclined to the left, the flight engineer called out "Bank" again three seconds after his first message . His tone of voice was more urgent this time, but he failed to give a more detailed indication of the now critical flight situation. The co-pilot, who was responsible for monitoring the instruments as “pilot not flying”, did not react in any way to the increasing inclination to the left.
media
The crash was discussed in the series Mayday - Alarm im Cockpit , season 11, episode 7, episode 79: Fatal system error (original title: Bad Attitude ).
In the documentation, the lack of reaction of the copilot and the imprecise expression of the flight engineer is justified with the age-hierarchical culture of Korea , which also prevails in the local military, from which the captain came. For dramaturgical reasons, it is clichéd that both crew members would not have intervened in order to avoid losing face . In fact, Korean Air was aware of the problem resulting from an overly strict hierarchy in the cockpit. Two years earlier, after the accident on Korean Air Flight 801 , the airline had strived to improve cockpit resource management in the company, but implemented it slowly.
Similar aviation accidents
Web links
- Aviation Safety Network: Accident Summary (in English)
Individual evidence
- ↑ a b c d e f g h Department for Transport: Report on the accident to Boeing 747-2B5F, HL-7451, near Great Hallingbury on December 22, 1999 , official accident report in English, accessed on February 5, 2017
Coordinates: 51 ° 51 ′ 23 " N , 0 ° 12 ′ 59" E