The NTSB ruled that pilot distraction was the cause of last fall’s overflight of its destination airport by a Northwest Airlines flight and the crew’s failure to maintain radio communications. The Safety Board also noted some deficiencies in air traffic control procedures, which it believed contributed to the duration of the event.
NWA Flight 188 was out of contact with air traffic control for more than one hour and 17 minutes on October 21 and had flown through several air traffic control sectors without replying to any radio transmissions from air traffic controllers. The Airbus A320 had missed its destination, Minneapolis, by more than 100 miles before communication with the flight crew was reestablished.
The Board found that the pilot and copilot were engaged in a conversation unrelated to the operation of the aircraft, and contrary to company policy, were operating personal laptop computers, as they tried to sort out company processes by which pilots select their flight schedules. During that period, the cockpit crew remained unaware of repeated attempts to contact them by air traffic control and the airline, until a flight attendant used the intercom to inquire about the flight status. The flight landed without further incident after authorities enacted protocols to ensure the flight crew was still in control of the aircraft.
The NTSB also faulted the lack of standard procedures for identifying flight crew-ATC communications in traffic control facilities that use automated flight-tracking systems. The failure of the air traffic controller to monitor whether the flight had switched to an assigned frequency was a factor in the delay of reporting lost communication with the aircraft. Since no radio (nordo) communications events are somewhat common, and usually of short duration, the Board noted that controllers might have become complacent in taking action in a timely manner.
In response to this and several other recent incidents, the NTSB is convening a three-day public forum in May to discuss professionalism in aviation and consider methods for ensuring excellence in pilot and air traffic controller performance.