MOSCOW (AP) The pilots of a Boeing 737 that plunged into the ground at Kazan airport lost speed in a steep climb then overcompensated and sent the plane into a near-vertical dive, according to a preliminary report released Tuesday by Russian aviation experts. All 50 people aboard were killed.
The Moscow-based Interstate Aviation Committee, which oversees civil flights in much of the former Soviet Union, said the plane's engines and other systems were working fine until the moment the plane crashed Sunday night.
The Tatarstan Airlines plane was flying from Moscow to the central city of Kazan, 720 kilometers (450 miles) to the east. The Russian aviation experts said the plane's two pilots had failed to make a proper landing approach on their first attempt, so they began a second try.
The report did not specify why the pilots aborted the first landing.
To get the plane ready for the second try, the pilots put the plane's engines on maximum power and raised the plane's nose up to an angle of about 25 degrees, the report said. That caused a loss of speed.
The normal procedure during an aborted landing is to apply near-maximum power and assume about a 5-to-7 degree nose-up attitude, said Kevin Hiatt, a former Delta Air Lines chief pilot and president of the Flight Safety Foundation, a U.S.-based nonprofit.
"Twenty-five degrees nose-up is excessive. There's no question about that whatsoever," Hiatt said. "Why they determined they needed to go to that high an angle will be part of the investigation."
At an altitude of about 700 meters (2,200 feet), the crew tried to gain speed and avert a stall by putting the nose of the plane down. The report said the plane then went into a dive of about 75 degrees and smashed into the ground.
Airplanes can sometimes recover from steep dives but they must be at a sufficiently high altitude.
The plane's climb and its subsequent plunge lasted only about one minute and it struck the ground going about 450 kilometers per hour (280 mph), the report said.
The report drew its conclusions from data retrieved from one of the plane's two onboard black box recorders. A commission statement said the voice-recording tape that captures the crew's conversations had not been found, even though its container had been recovered.
Such "loss of control" accidents are responsible for more deaths than any other type of plane crash because they are rarely survivable, according to the Flight Safety Foundation, an industry-supported global aviation safety nonprofit based in Alexandria, Virginia.
The head of Tartarstan Airlines, Aksan Giniyatullin, told a news conference Tuesday in Kazan that the two pilots had plenty of flying experience ranging from 1,900 to 2,500 hours and had undergone all the necessary instruction. However, he said the crew apparently had no experience with attempting a second landing.
He also said the plane had undergone regularly scheduled maintenance on Nov. 15 two days before the crash.
Tartarstan Airlines records showed that the plane was built 23 years ago and had been used by seven other carriers prior to being picked up by them in 2008. The company has insisted that the aircraft was in good condition.
The plane did suffer a loss of cabin pressure in November 2012, Giniyatullin told reporters, but he could not explain why, according to the RIA-Novosti news agency.
In 2001, the plane was damaged in a landing accident in Brazil that injured no one.
The carrier has had a good safety record but appears to have run into financial problems recently. Its personnel went on strike in September over back wages, and the Kazan airport authority has gone to arbitration to claim Tatarstan Airlines' alleged debt for servicing its planes.
Flight safety is a problem in Russia. Industry experts have blamed some recent Russian crashes on a cost-cutting mentality that neglects safety in the chase for profits. Insufficient pilot training and lax government controls over the industry have also been cited.
Associated Press writer Joan Lowy in Washington, DC, contributed to this report.