Turkish Airlines Flight 634
 TC-THG , the aircraft involved in the accident, landing at Budapest Airport in February 2001. | |
| Accident summary | |
|---|---|
| Date | 8 January 2003 |
| Summary | Controlled flight into terrain, pilot error |
| Site | Diyarbakır Airport, Diyarbakır, Turkey |
| Passengers | 75 |
| Crew | 5 |
| Fatalities | 75 |
| Injuries (non-fatal) | 3 |
| Survivors | 5 |
| Aircraft type | BAe Avro RJ100 |
| Aircraft name | Konya |
| Operator | Turkish Airlines |
| Registration | TC-THG |
| Flight origin | Istanbul Atatürk Airport, Istanbul, Turkey |
| Destination | Diyarbakır Airport, Diyarbakır, Turkey |
Turkish Airlines Flight 634 was a scheduled domestic passenger flight from Turkish Airlines' hub at Istanbul Atatürk Airport to Diyarbakır Airport in southeastern Turkey. On 8 January 2003 at 20:19 EET (18:19 UTC), the aircraft operating the flight, a British Aerospace Avro RJ100 struck the ground on final approach approximately 900 metres (3,000 ft) short of the runway threshold during inclement weather conditions. In the following collision with a slope, a post-crash fire broke out, killing 75 of the 80 occupants on board, including both pilots.
Background
Aircraft
The aircraft involved in the accident was a 1993-built British Aerospace Avro RJ100 with manufacturer serial number E3241. Owned by Trident Jet (Dublin) Limited, it was equipped with four Lycoming LF507-1F turbofan engines and performed its first flight in March 1994. Until the time of the accident, it had accumulated a total of 19,289 flight hours in a total of 16,659 flight cycles.[1][2]
Crew and passengers
The aircrew consisted of two pilots and three flight attendants. Captain Alaaddin Yunuk, former Turkish Air Force pilot aged 34, had joined Turkish Airlines in 1995 and had accumulated 6,309 flight hours in total. First Officer Ismail Uluslu, aged 33, had joined Turkish Airlines in 1998 and had since clocked 2,052 flight hours in total. Both pilots were joined by three flight attendants who completed the five-strong crew. The flight was carrying 75 passengers. Of the 80 occupants on board, initially six passengers survived but one passenger later succumbed to his injuries.[3]
Accident
Flight 634 departed Istanbul Atatürk Airport at 18:43 EET (16:43 UTC) for the nearly two-hour flight to Diyarbakır in southeastern Turkey. Approximately one hour into the flight and 40 nautical miles (74 km) off the destination airport, the crew contacted Diyarbakir Airport's approach control which cleared the flight to approach the airport from the south for runway 34 using VHF omnidirectional range – a type of short-range radio navigation system which enables aircraft with a receiving unit to determine their position and stay on course – and instructed the crew to descend to 9,000 feet (2,700 m). The weather report relayed to crew by the controller stated no winds and visibility of 3,500 metres (1.9 nmi).[1][4][5][6]
At a distance of 8 nautical miles (15 km) from runway 34 at an altitude of 5,000 feet (1,500 m), air traffic control instructed the crew to continue its approach and report as soon as they have established visual contact to the runway. The crew acknowledged the call and prepared the aircraft for landing, deploying the landing gear and extending the flaps.
Continuing to descend, the aircraft reached its minimum descent altitude (MDA) of 2,800 feet (850 m) – the lowest altitude, to which descent is authorized on final approach or during circle-to-land maneuvering in execution of a standard instrument approach procedure where no electronic glideslope is provided (the airport was not equipped with an instrument landing system) – but both pilots expressed that there was still no visual reference to the runway or its approach lighting system due to the thick fog. He only discerned some lights in the distant but was not sure as to what they exactly belonged to.[1][7]
Nonetheless, violating standard procedures, the captain decided to continue the approach to as close as 1 mile (1.6 km) to the runway and descended further to 500 feet (150 m) and beyond, well below the MDA. At 1 mile (1.6 km) off the threshold of the runway and at an altitude of 200 feet (61 m) (which in this case constituted the decision height), the ground proximity warning system (GPWS) started to trigger aural alarms. Eight seconds later, the crew decided to abort the landing and initiated a go-around but eventually, before being able to execute the command, struck the ground with the undersurface of its fuselage and its landing gear at 20:19 EET (18:19 UTC) 900 metres (3,000 ft) off the threshold of runway 34 and 30 metres (98 ft) off the approach lights at a speed of around 131 knots (243 km/h).[1][8]
The aircraft slid around 200 metres (660 ft) on ground as it started to disintegrate. Eventually, the aircraft hit a slope, broke up into three major pieces, exploded and caught fire which burnt most of the bodies and parts of the wreckage. The debris was spread out in an area of about 800 square metres (8,600 sq ft).[1][9]
The impact instantly killed both pilots, the three flight attendants and 69 of the 75 passengers. Six passengers survived of whom one however later succumbed to his injuries in hospital.[1]
Immediate Response
Since the crash site was within the boundaries of the airport, search and rescue teams of the 2nd Tactical Air Force Command stationed at Diyarbakır Air Base which included two helicopters, were quickly deployed. However, neither helicopter was able to participate in the rescue efforts due to the dense fog which, to eyewitness accounts, was below one metres at times. Numerous firetrucks and amulances were deployed to extinguish the post-crash fire and rescue the victims.[9][10]
Investigation
The investigation into the accident was carried out by Turkey's Directorate General of Civil Aviation (DGCA). Both flight recorders – the cockpit voice recorder (CVR) and the flight data recorder (FDR) – were found intact and were sent to Turkish Airlines' laboratories for analysis.
According to records, Captain Alaaddin Yunuk and first officer Ismail Uluslu were found to have been properly trained, qualified and experienced enough. They had sufficient rest before reporting for duty at the day of the accident. Drug and alcohol tests returned negative results.
Investigators also turned their attention to the aircraft but were not able to detect any abnormalities. All maintenance checks were completed properly. Close examination of the engines revealed that they were operating normally at the time of the accident. The aircraft was properly configured for landing – the flaps and the landing gear were extended properly and the altimeter was set correctly – and the ground proximity warning system (GPWS) also produced alarms which could be easily heard on the CVR recordings.
Search and rescue teams who rushed to the site immediately to respond to the crash reported thick fog at the crash site and complained about the lack of visibility which according to their account was as low as 1 metre (3.3 ft) at times. This clearly contradicts the weather report the air traffic controller at Diyarbakır Airport has relayed to the crew minutes before the crash. According to them, the fire could not even be seen until arriving on the scene.
Analysis of the FDR and the CVR revealed that at the moment the aircraft struck the ground it was at a heading of 339° (north-northwest, in line with the runway centerline) and 900 metres (3,000 ft) short of the threshold of runway 34 at a positive pitch rate of five degrees (which corresponds to a slight nose-up position). The autopilot was found to have been activated up until a short moment before the accident.
Final Report
The investigation was completed around two years later in April 2005 and concluded that:[1]
- The crew failed to properly respond to the warnings produced by the GPWS and instead insisted to land despite insufficient visual reference to the runway and its environment
- Thick fog contributed to the cause of the accident.
The 'Turkey Airline Pilots Association' has expressed that an existing Instrument landing system might have prevented the accident.[11]
See also
- Crossair Flight 3597 – An Avro RJ100 which crashed in similar circumstances.
References
- 1 2 3 4 5 6 7 "Kaza Kırım" (in Turkish). Sivil Havacılık Genel Müdürlüğü. 25 October 2004. Archived from the original on 14 June 2008. Retrieved 25 August 2016.
- ↑ "Hava Aracı Kazası Nihai Raporu" (PDF) (in Turkish). Sivil Havacılık Genel Müdürlüğü. 1 April 2005. Retrieved 25 August 2016.
- ↑ "Scot killed in Turkey air crash". BBC. 9 January 2003. Retrieved 28 December 2008.
- ↑ "Diyarbakır'daki Uçak Kazasında Ölen 75 Kişiden 61'i Teşhis edildi" (in Turkish). Haber Vitrini. Retrieved 29 December 2008.
- ↑ "Tutanak" (PDF) (in Turkish). TÜRKİYE BÜYÜK MİLLET MECLİSİ. 9 September 2005. Retrieved 25 August 2016.
- ↑ "TBMM Başkanlığına" (PDF) (in Turkish). TÜRKİYE BÜYÜK MİLLET MECLİSİ. 21 July 2005. Retrieved 25 August 2016.
- ↑ "MİLLİYET İNTERNET - GÜNCEL HABERLER". www.milliyet.com.tr. Retrieved 2016-08-23.
- ↑ "Kaza Değil İntihar". Retrieved 2016-08-23.
- 1 2 "Diyarbakır'da THY uçağı düştü" (in Turkish). NTV MSNBC. 9 January 2003. Retrieved 28 December 2008.
- ↑ "Turkish Airlines plane crashes, 75 dead, 5 survivors". CNN. 8 January 2003. Retrieved 29 December 2008.
- ↑ "'ILS olsaydı kaza riski en aza inerdi'" (in Turkish). NTV MSNBC. 9 January 2003. Retrieved 28 December 2008.