Officials are still investigating what caused a small commuter plane to crash out of the sky over Alaska last week, killing all 10 people aboard — but Joel Natwick, a longtime pilot in the state, thinks ice could be to blame.

The cause of the crash is still under investigation. All nine passengers and the pilot were killed, making it one of the deadliest plane crashes in the state in 25 years

The Cessna Caravan left Unalakleet at 2:37 p.m., and officials lost contact with it less than an hour later, according to David Olson, director of operations for Bering Air. The aircraft was 12 miles (19 kilometers) offshore, according to the U.S. Coast Guard.