The Bering Air Caravan, a single-engine turboprop, was heading from Unalakleet to Nome on Thursday afternoon with nine passengers and a pilot, according to Alaska’s Department of Public Safety. Authorities were working to determine its last known coordinates.

Unalakleet is a community of about 690 people in western Alaska, about 150 miles (about 240 kilometers) southeast of Nome and 395 miles (about 640 kilometers) northwest of Anchorage.

The disappearance marks the third major incident in U.S. aviation in eight days. A commercial jetliner and an Army helicopter collided near the nation’s capital on Jan. 29, killing 67 people. A medical transportation plane crashed in Philadelphia on Jan. 31, killing the six people onboard and another person on the ground.