Complex sentence: The Israeli Air Forces confirmed that it lost contact with one of the helicopters, which had crashed at approximately 4:00 P.M. at an altitude of 2,246m (7,369ft).
Split into simpler sentences: 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 2,246m (7,369ft).