Korean Air Flight 007 [KAL 007] was a Boeing 747-200 shot down by a Soviet SU-15 ‘Flagon’ Interceptor on 1 September, 1983. This well-known incident occurred over the sea of Japan, near Sakhalin island, in Soviet airspace. The 747 was flying from Anchorage to Seoul, but due to the pilots' mishandling of the autopilot, inadvertently flew over Kamchatka peninsula and Sahkalin island. There were a number of factors that may have contributed to this accident, some of which will be discussed below.
Image embedded from Wikipedia on 18 August, 2010
The 747’s autopilot has four modes: HEADING, INS, ILS, and VOR. After takeoff, the pilots were assigned a magnetic heading to overfly the town of Bethel, from where they could select INS mode to fly a series of waypoints across the Pacific ocean. When the aircraft neared Bethel, the pilots most likely selected INS [INERTIAL NAVIGATION] mode (Degani, 20032; ICAO, 19933). There is also a possibility that the pilots left the autopilot in HEADING mode, although this is considered not very likely. The autopilot mode display subsequently changed from ‘HEADING’ to ‘INERTIAL NAVIGATION ARMED’. This meant that the aircraft was not close enough to Bethel for the INS mode to activate and was still flying in HEADING mode. Over their many years of flying the 747 and selecting INS, the pilots had likely become conditioned to seeing ‘INERTIAL NAVIGATION’, which is displayed when INS mode engages. They therefore possibly ‘saw what they wanted to see’, or possibly thought that ARMED meant engaged. Also, there was no indication that HEADING mode was still active. This ambiguous design lead the pilots to believe that the INS mode was taking them to Seoul, when in fact the HEADING mode was taking them towards Soviet airspace. After this accident, the 747’s autopilot display was redesigned to prevent such accidents occurring again.
Lack of Situational Awareness
While the pilots had committed this error, there were at least three factors that could have told them they were flying off course. The first was the HSI (Horizontal Situation Indicator).
This instrument would have instantly told the crew they were flying off course, but for whatever reason, this was not noticed. The second event was the poor VHF radio conditions the crew was experiencing. It required them to relay some radio calls through another Korean Air Lines flight, fifteen minutes behind them. While communicating with this other aircraft, the crew realised that the two aircraft, supposedly fifteen minutes apart on the same route, were experiencing winds 180 degrees apart. The fact that these irregularities were overlooked suggests the pilots had a chronic lack of situational awareness, possibly due to the factors outlined below.
Crew's Recent History
There are several factors that lead the pilots to first mishandle the autopilot, and then to not realise their divergence with their intended track. The pilots were possibly fatigued, having been awake for several hours before the departure time of 04:00. As the flight was returning to Seoul, the crew was possibly distracted with thoughts of home. Furthermore, it is likely that due to the relative inactivity on this long-distance international flight, the crew’s arousal level was low. The combination of these factors could have had four significant effects on performance:
- Short- and long-term memory lapses may have resulted in the pilots missing the significance of 'INERTIAL NAVIGATION ARMED’.
- Reduced level of alertness meant the pilots possibly did not realise the HSI was showing track divergence, they 'looked but did not see'.
- Tendency to avoid making effort may have resulted in the pilots not checking the HSI at all.
- Impaired logical reasoning and impaired ability to integrate information meant the pilots did not realise they were flying off-course when presented with contradictory winds and bad VHF reception.
The end result being the crew was less likely to realise their increasing divergence with their intended track, which cost 269 people their lives.
As with many aircraft accidents, there is no single factor that lead KAL 007 to be erroneously shot down in Soviet airspace. Following James Reason's Accident Causation Model, both acitve and latent errors can be identified.
There were two main active errors committed by the flight crew during this flight. First, mishandling the autopilot navigation system, and second, not maintaining sufficient situational awareness to realise they were flying off course. If either error had not been committed, the accident would not have occurred.
One latent error was the poorly designed autopilot interface. Five years after the accident, Blache (19881) suggests that there were three main flaws with the 747's autopilot system [latent errors] that contributed to the downing of KAL 007.
1) The process of programming and activating the autopilot navigation system has a high opportunity for errors to be committed, and no feedback giving the pilots a chance to recognise possible errors.
2) Operation of the autopilot navigation system is a passive monitoring task. This can lead to decreased vigilance on behalf of the pilots.
3) The procedures for operating the autopilot navigation system had not been analysed by a human factors specialist to identify possible design deficiencies.
These are latent errors because they were committed long before the accident, when the autopilot was being designed and tested, and did not directly affect safety at the time. The autopilot could been designed to better warn the flight crew when the INS mode did not engage. This could be done with a flashing light, an audible tone and a message "INS capture failed, HEADING mode active" or similar. It generally believed that accidents can be best prevented by dealing with these latent errors, rather than preventing active errors. The reason for this is that pilots, being human, will continue to make errors, and it is therefore difficult to reduce active errors. However, the operator that commits the active error is usually the final trigger in a series of latent errors. Identifying the poor design of the 747 autopilot and redesigning it meant that this latent error has been removed, and probability of this this type of accident occurring in the future is significantly reduced.
A final possible factor influencing the outcome of this flight was the airline’s culture, which may have discouraged the FO to question the Captain over these discrepancies. A high power distance, one of Geert Hofstede’s four dimensions of culture, would encourage the FO to act subordinate to the Captain, and to avoid questioning his authority. Asian flight crews tend to maintain a high power distance, with First Officers treated as subordinates, and Captains holding almost absolute power (Kern, 20014). It is possible that the FO noticed these above inconsistencies [see 'Lack of Situational Awareness' above], and perhaps realised they were drifting off course. However, nothing was said, and the pilots of KAL 007 continued their flight towards disaster.