Searchers combed the rugged terrain of north-central Georgia on Wednesday for a missing Navy plane carrying four aviators.

The Navy T-39 Sabreliner left Chattanooga, Tenn., Tuesday morning, and was scheduled to arrive in Pensacola, Fla., that afternoon but never did, said a spokesman, Lt. j.g. Sean Robertson.

The last radio contact with the plane was at 11:20 a.m., about 20 minutes after takeoff, Robertson said.

"All we know is the aircraft made contact, and we haven't heard anything since," he said.

Searchers were looking in an area that includes Carters Lake, but the effort was hampered by rugged terrain and rainy weather.

A Navy instructor, a Navy student, an Air Force student and a civilian contract pilot were aboard the Sabreliner, Robertson said. Their identities have not been released.

Sabreliners are used for training navigators and other non-pilot air crew officers for the Navy, Marine Corps, Air Force and foreign military services.