MEDAN, Indonesia — A small plane on a local flight in western Indonesia crashed into a mountainous area today and all 18 people aboard were feared dead, officials said. Rugged terrain and rains hampered searchers trying to reach the wreckage.

The Spanish-designed CASA C-212 was about halfway through its 30-minute flight between North Sumatra and Aceh provinces when it lost contact with air traffic control.

Minutes later, the turboprop-powered aircraft sent out a distress signal and then dropped off the radar.