BLAIR, Neb. (AP) — Authorities say the fatal crash of a glider near Blair Airport occurred soon after the aircraft’s canopy opened unexpectedly as the glider was being towed aloft.

Nebraska authorities have identified the pilot as 59-year-old Michael Boska, who lived in Glenwood, Iowa. The crash occurred around 3:30 p.m. Saturday.

Witnesses say that after the canopy opened, Boska lost control of his glider. It went airborne but soon plunged and crashed while still attached to the tow plane.

Federal investigators have been called in.