Federal investigators say the two planes that collided midair near Boulder were flying in clear weather and not performing maneuvers when the accident occurred.

Those were among the details released Monday of the crash that killed all three occupants in both planes Saturday. Witnesses told investigators that the Cirrus SR-20 aircraft hit the Piper Pawnee at a 90-degree angle and that a glider being towed by the Piper Pawnee disconnected just before impact.

Killed in the accident were 58-year-old Bob Matthews and his 56-year-old brother, Mark, both of Boulder, and 25-year-old Alexander Howard Gilmer of Evergreen.

The glider pilot landed safely.

The investigator also says the Cirrus aircraft took off from the airport in Erie, not Boulder.

Investigators will piece together the aircraft Tuesday.