KAZAN (QHA) - Russia's aviation safety watchdog says a preliminary investigation suggests pilot error may have caused the fatal crash of a Tatarstan Airlines plane in Kazan on November 17, Radio Free Europe Radio Liberty informs. The Interstate Aviation Committee said on November 19 that the pilots of the Boeing 737 somehow lost their plane's speed at a low altitude, resulting in the near-vertical plunge that killed all 50 people on board. It said the crew had failed to make a proper landing approach on their first attempt before making a second run. Finding out the plane's altitude was not high enough, they performed a series of faulty maneuvers which resulted in the plunge. The committee said the plane's engines and other systems were working fine until the moment the aircraft hit the ground. As reported earlier, the Boeing 737 operated by Tatarstan Airlines crashed on November 17 while trying to land in Kazan, killing everyone on board.