SAN DIEGO -- Federal investigators sought Friday to determine what caused the pilots of a Northwest Airlines jetliner to lose contact with air-traffic controllers for more than an hour and overshoot their destination by 150 miles during a flight from San Diego to Minnesota.

The Airbus A320 landed safely at Minneapolis-St. Paul International Airport on Wednesday evening after the crew re-established radio contact, turned the plane around and backtracked to the west, according to the National Transportation Safety Board.

After landing, airport police and FBI agents interviewed the two pilots, who told them they'd "lost situational awareness" after getting into a "heated discussion over airline policy" during the flight, according to an NTSB statement.

The pilots have been suspended from flying pending results of the investigation.

Air controllers lost contact with the flight at 5:56 p.m. Mountain Daylight Time, as the jetliner with 147 passengers aboard was cruising at an altitude of 37,000 feet, according the NTSB. Just over an hour later, the plane passed over its destination airport and continued heading northeast.

Communications between the airliner and the ground resumed at 8:14 p.m. Central Daylight Time.

The incident had no effect on operations at Lindbergh Field, said Steve Shultz, a spokesman for the airport alongside San Diego Bay.

The plane's cockpit voice recorder and flight data recorder have been sent to an NTSB laboratory in Washington, D.C., for analysis.