The Navy has called off a search for an electronic warfare plane that failed to return from a training mission 900 miles off the West Coast and said Tuesday the four crewmen were presumed lost.

Several pieces of debris were spotted from search aircraft but sank before they could be recovered, said Navy spokesman Lt. Gordon Hume. The search was ended at 5:30 p.m. Monday, he said.The EA6-B "Prowler" took off from the aircraft carrier USS Constellation late Sunday and was declared overdue early Monday, prompting a sea and air search, said Navy spokesman Lt. Cmdr. Bob Pritchard said.

The twin-engine jet was assigned to Tactical Electronics Warfare Squadron VAQ-139 at the Whidbey Island (Wash.) Naval Air Station, said Public Affairs Officer Howard Thomas at Whidbey Island.