Officials from the US National Transportation Safety Board (NTSB) are investigating what happened to a Northwest Airlines A320 (N03274) with 147 passengers that lost radio communications for 1h and 16 min on a flight from San Diego to Minneapolis last night.

The aircraft overflew the airport at its cruise altitude of 37,000ft, flying an additional 150nm in a northeast direction before re-establishing communications with Minneapolis air traffic controllers and returning to the airport.
Flight 188, scheduled to arrive at 2004h local time, landed one hour late due to the diversion.

The controller who regained communications with the crew "reportedly stated the crew had become distracted and had over flown (the airport), and requested to return to (the airport)", according to the NTSB.

However, officials note that when the crew was interviewed by the Federal Bureau of Investigation (FBI) and airport police, they had stated that they were "in a heated discussion over airline policy and they lost situational awareness".

Along with securing the cockpit voice and flight data recorders, investigators are also scheduling an interview with the crew. No one was injured in the incident.