On 26 July 2010 at 1:15 P.M., two Yasur helicopters took off from the Romanian Air Force Base in Boboc and headed north toward the Carpathian mountains.
The fog which prevailed at the flight altitude made it difficult to navigate.

The two helicopters were flying in formation at a low altitude as part of the exercise.
 While over the Carpathian Mountains in Romania, one of the helicopters radioed that it had lost visual and radio contact with its counterpart.
 The Israeli Air Force confirmed that it lost contact with one of the helicopters.
 The helicopter had crashed at approximately 4:00 p.m. at an altitude of 2,246 m (7,369 ft).
On 26 July 2010 at 1:15 P.M., two Yasur helicopters took off from the Romanian Air Force Base in Boboc and headed north toward the Carpathian mountains. The fog which prevailed at the flight altitude made it difficult to navigate.
The two helicopters were flying in formation at a low altitude as part of the exercise.  While over the Carpathian Mountains in Romania, one of the helicopters radioed that it had lost visual and radio contact with its counterpart.  The Israeli Air Force confirmed that it lost contact with one of the helicopters.  The helicopter had crashed at approximately 4:00 p.m. at an altitude of 2,246 m (7,369 ft).
2010 IAF Sikorsky CH-53 crash