In 1991 an Air Canada flight ran into big trouble. Passengers were enjoying an in-flight movie on the Boeing 767 when the jumbo jet's massive engines abruptly stopped. At first only those without earphones on noticed anything. However, soon it was apparent the jet was in trouble. The pilot came on the speaker system and announced that Flight 143 would be making an emergency landing. The 69 people on board were trapped in an agonizingly slow but inescapable descent to earth.

For several minutes a desperate silence hung over the cabin. Then fear gave way to screams of anxiety as the landing neared.…