5:10 p.m.: 16-year-old Heidi Landseth is in her home near New York City. Her parents are away on business and she is lonely and bored. 5:15 p.m.: Across town, 17-year-old Patrick Farquhar, a volunteer rescue worker, longs for an emergency. 5:30 p.m.: Flight #116, a 747 jumbo...