The deadliest U.S. airline disaster prior to the Sept. 11 attacks on the World Trade Center and Pentagon was the July 17, 1996, midair explosion that destroyed TWA Flight 800 off the coast of Long Island, N.Y. Six years later, while the official investigation has been closed (or forever forgotten in "inactive pending" status), the nature of the explosion that killed the 230 passengers of the Paris-bound jumbo jet is very much on the radar of independent investigators. Indeed, investigators now have used the government's own regulations to petition the National Transportation Safety Board (NTSB) for a reconsideration and modification...