WASHINGTON — Not sleeping, the pilots say. They were engrossed in a complicated new crew-scheduling program on their laptop computers as their plane flew past its Minneapolis landing by 150 miles — a cockpit violation of airline policy that could cost them their licenses.
They were so focused on the scheduling — quite a complicated matter for the pilots after Delta Air Lines acquired Northwest Airlines a year ago — that they were out of communication with air traffic controllers and their airline for more than an hour.
They didn't realize their mistake until contacted by a flight attendant about five minutes before the flight's scheduled landing last Wednesday night, the National Transportation Safety Board said Monday.
By then, Northwest Flight 188 with its 144 passengers and five crew members was over Wisconsin, at 37,000 feet.
The pilots — Richard Cole of Salem, Ore., the first officer, and Timothy Cheney of Gig Harbor, Wash., the captain — denied they had fallen asleep as aviation experts have suggested, the safety board said in recounting investigators' interviews with the men over the weekend.
Instead, Cole and Cheney said they both had their laptops out while the first officer, who had more experience with scheduling, instructed the captain on monthly flight crew scheduling.
A number of aviation experts — and people wondering about their next airline flights — have suggested it was more plausible that the pilots had fallen asleep during the San Diego-to-Minneapolis flight.
Air traffic controllers in Denver and Minneapolis repeatedly tried without success to raise the pilots by radio. Other pilots in the vicinity tried reaching the plane on other radio frequencies. Their airline tried contacting them using a radio text message that chimes.
Authorities became so alarmed that National Guard jets were readied for takeoff at two locations and the White House Situation Room alerted senior officials, who monitored the Airbus A320.
"It's inexcusable," said former NTSB Chairman Jim Hall. "I feel sorry for the individuals involved, but this was certainly not an innocuous event — this was a significant breach of aviation safety and aviation security."
Delta said in a statement that using laptops or engaging in activity unrelated to the pilots' command of the aircraft during flight is strictly against the airline's flight deck policies. The airline said violations of that policy will result in termination.
No federal rules specifically ban pilots' use of laptops or other personal electronic devices as long as the plane is flying above 10,000 feet, said Diane Spitaliere, a Federal Aviation Administration spokeswoman.
"I think it depends upon how it's being used," Spitaliere said.
The Air Transport Association, a trade group that represents major U.S. airlines, expects pilots to comply with federal regulations and airline policies, but hasn't taken a position on the use of electronic devices by pilots while in the cockpit, ATA spokeswoman Elizabeth Merida said.
Delta has suspended the two pilots pending an investigation. FAA is also investigating and has warned Cheney and Cole their pilot licenses could be suspended or revoked.
Pilots' schedules are tied to their seniority, which also determines the aircraft they fly. Those at the top of the list get first choice on vacations, the best routes and the bigger planes that they get paid more for flying. Following Delta Air Lines' acquisition of Northwest, an arbitration panel ruled that the pilot seniority lists at the two carriers should be integrated based on pilots' status and aircraft category.
Cheney and Cole are both experienced pilots, according to the NTSB. Cheney, 53, was hired by Northwest in 1985 and has about 20,000 hours of flying time, about half of which was in the A320. Cole, 54, had about 11,000 hours of flight time, including 5,000 hours in the A320.
Both pilots told the board they had never had an accident, incident or violation, the board said.
The pilots acknowledged that while they were engaged in working on their laptops they weren't paying attention to radio traffic, messages from their airline or their cockpit instruments, the board said. That's contrary to one of the fundamentals of commercial piloting, which is to keep attention focused on monitoring messages from controllers and watching flight displays in the cockpit.
"It is unsettling when you see experienced pilots who were not professional in flying this flight," said Kitty Higgins, a former NTSB board member. "This is clearly a wakeup call for everybody."