Federal officials said that the two Northwest Airlines pilots who overflew Minneapolis-St. Paul by more than 150 miles became so distracted by a conversation over flight schedules that they failed to hear repeated radio calls.
However, a report released Thursday by the National Transportation Safety Board also placed some blame for the errant flight on air traffic controllers, and it recommended changes in the way flight crews communicate with controllers.
The pilots failed to maintain radio communication because they became distracted by a conversation over changes to the process for requesting flight schedules -- changes resulting from the merger between Northwest and Delta Air Lines. The conversation was so engrossing that the pilots missed "at least nine messages regarding their position" as they neared the Minneapolis-St. Paul airport, and entered the airport without landing data entered into the flight management computer, the NTSB's findings said.
The two pilots, Timothy Cheney of Gig Harbor, Wash. and Richard Cole of Salem, Ore., had their licenses revoked in October, but can reapply for them in August. The pilots could not be reached to comment.
The NTSB's report ends a six-month investigation into the flight's errant path last October and confirms earlier reports, based on interviews with the flight crew, that pilots were not adequately focused on operating the Airbus A320. The flight from San Diego landed safely in Minneapolis with no injury to its crew and 144 passengers.
However, the report also found significant lapses by air traffic controllers, and recommended new communication procedures between flight crews and controllers.
The NTSB said in its statement Thursday that recent accidents and incidents "have demonstrated the clear hazards to aviation safety when pilots and air traffic controllers depart from standard operating procedures." In August, a midair collision of an airplane and a helicopter killed nine people over the Hudson River, and the crash last February of Pinnacle Airline Corp.'s Colgan Air flight 3407 near Buffalo, N.Y., left 50 people dead.
The crew of the Northwest Airlines flight did not communicate with air traffic controllers for 77 minutes, the NTSB found. According to the report, the Northwest pilots were not aware of some 25 attempts by controllers and the airline to contact them until a flight attendant used the intercom to inquire about the progress of the flight.