It's never a good sign when pilots of a plane carrying 144 souls do not respond to the inquiries of air-traffic controllers or airline officials for more than an hour and 15 minutes. Just as fighter aircraft were being prepared to be scrambled out of fear of foul play, Northwest Flight 188, flying from San Diego to MinneapolisSt. Paul, re-established contact. Its pilots, Timothy Cheney and Richard Cole, had been so absorbed in what they were doing on their laptops apparently they were looking into the new monthly flight-crew-scheduling procedures that they simply lost track of time. When a concerned flight attendant finally buzzed them over the intercom to ask how things were going, they were already somewhere over Wisconsin. They're now in a holding pattern; the FAA has revoked their pilot certificates