One of his firm's most accomplished engineers, holding two patents in encryption. He was on a last-minute trip west. Five minutes before the end he locked himself in a lavatory and dialled 911 from his mobile telephone, reporting a hijacking in progress and identifying himself and his flight.

Killed aboard United Airlines Flight 93, which came down in a field near Shanksville, Pennsylvania, on the morning of 11 September 2001. The aircraft had left Newark forty-two minutes late, which is the only reason those aboard learned by telephone what had already happened in New York before theirs was taken. They had about thirty minutes. They voted, and they went forward at the cockpit door. The aircraft never reached what it was aimed at.