WASHINGTON - A call from a flight attendant to the pilots of the Northwest Airlines plane that overshot Minneapolis catapulted the cockpit crew from complacency to confusion.

Interviews with the flight crew and other documents released yesterday by the National Transportation Safety Board show the pilots were unaware of their predicament until the intercom rang.

They were unaware that they had flown their Airbus A320 with 144 passengers more than 100 miles past their destination; that air traffic controllers and their airline's dispatchers had been struggling to reach them for more than an hour; or that the military was readying fighter jets for an intercept.

Timothy Cheney, captain of Flight 188, said he looked up from his laptop to discover there was no longer any flight information in the Airbus A320's computer. He said his navigation system showed Duluth, Minn., to his left and Eau Claire, Wis., ahead on the right.

The plane had been out of radio contact for 77 minutes as it flew across a swath of the country Oct. 21, raising national security concerns.

Cheney, 54, and First Officer Richard Cole, 54, told investigators they had taken out their laptops and were working on a complicated crew scheduling program they were required to learn after Delta Air Lines' acquisition of Northwest a year earlier.

Cole said they became distracted as they "got deeper and deeper into it."

Investigators wrote that Cheney felt embarrassed. They quote him as saying, "I was wrong," and that he "let another force come from the outside and distract me."

A flight attendant told investigators the lead pilot answered on the third ring and sounded surprised when she asked about the arrival time.

"It was as though he had to think about it," the report said, based on information from flight attendant Barbara Logan.

Interviews with Cheney and Cole also hint at tension between them. The pair were flying together for the first time. Cheney characterized Cole's piloting skills as "OK, but I've flown with better." Both are appealing the Federal Aviation Administration's revocation of their licenses.

Flight 188 wasn't the only Northwest operation that was hard to reach that night.

A controller who called Northwest's dispatchers to ask them to contact the plane first encountered a recording telling him the phone number had been changed. He dialed the new number, but the phone rang 10 to 20 times without being answered, he told investigators. He hung up, then redialed.

This time, someone at the dispatch office answered - and put him on hold.

The FAA has said the phone numbers controllers had for Northwest predated its acquisition by Delta and have now been updated.

The first controllers the pilots spoke to after becoming aware of their situation were in Winnipeg, Canada.

They had failed to switch their radio frequency from one used by controllers in Denver to one used by Minneapolis. They were still using the Denver frequency - which is the same as Winnipeg's - when they tried to reach air traffic control.