BOISE, Idaho — Two small planes collided in midair in central Idaho Friday, killing at least one person.

The Federal Aviation Administration reports a single-engine Piper Tri-Pacer and a twin-engine Beechcraft Baron collided in midair at 9:50 a.m. under unknown circumstances at Johnson Creek, a backcountry air strip near Yellow Pine.

Two people were seriously injured. The condition for the fourth person wasn't given, the FAA said.

The agency says that the National Transportation Safety Board will be the lead investigator into the cause of the collision.

The identities of those aboard the aircraft or the planes' tail numbers haven't been released.

Johnson Creek Airport has a grass runway and is a popular spot for backcountry aviation enthusiasts seeking access to mountainous terrain adjacent to the Frank Church River of No Return Wilderness.