Russian investigators have determined that the Itek Air Boeing 737-200 which crashed in Kyrgyzstan on 24 August lost height during an orbit while attempting to stabilise its approach to Bishkek Manas airport.
Preliminary information from the inquiry shows the aircraft was trying to return to Bishkek, minutes after taking off for Tehran, following a pressurisation problem.
But Russia's Interstate Aviation Committee (MAK) states that there is no evidence of any other technical fault on the twinjet.
MAK has detailed the moments leading up to the accident after managing to derive information from the fire-damaged flight-data recorder.
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"So far a recording of almost the entire flight has been restored and synchronised," it says, adding that work is continuing on decoding the last three or four seconds of data.
The aircraft, with 83 passengers, seven crew members and a take-off weight of 47t, departed Bishkek's runway 08 at 20:30. It followed a standard departure procedure, designated DW-1, making a left turn to a heading of 240°.
About seven minutes after take-off, when the 737 had reached an altitude of about 9,840ft (3,000m) and was 37km (20nm) from the airport, the crew opted to return because of a pressurisation issue.
Visibility was good at the time and the pilots planned a visual approach to runway 08. The aircraft turned right, to head back to the airport, and descended to an altitude of 3,400ft - equivalent to 1,300ft above airport elevation.
Some 12min into the flight the crew reported visual contact with the runway and, about a minute later, the 737 was 12km from touchdown and travelling at 250kt.
Maintaining a height of 1,300ft, the crew began to slow the aircraft until it reached 185kt at 5km distance. But MAK says that the approach was not stabilised with respect to altitude, speed and configuration, and the crew requested a left-hand orbit.
Air traffic control cleared the orbit and the aircraft began a left turn with up to 30° of bank. As the aircraft turned, it descended and its speed dropped to 155kt. MAK says that, within a short time, the jet was travelling at an "extremely low altitude".
With its undercarriage deployed and its flaps set at 15°, the aircraft struck the ground about 7.5km from the end of runway 08. Twenty-five of those on board survived the crash.
Source: Flight International
