1. A static spark too weak to see in daylight can be strong enough to ignite a mixture of fuel vapor and air in the ideal concentrations. 2. Even so, the attraction of a static spark as a theory is clear. 3. If the tank had been full of cold fuel, or nearly so, a static spark probably would not have ignited it. 4. Investigators have seized on the idea of a static spark or a tiny explosive device, neither of which would necessarily have left enough evidence to be detected. 5. Like the tiny, undetectable explosive device, a static spark is a theoretical possibility. 6. Proving that a static spark is possible, though, does not prove that it happened. 7. The aviation investigators have settled on a static spark as a likely culprit because all other identified mechanical ignition sources appear even less likely. 8. The report said a static spark caused the explosion of a fuel tank when it came into contact with an air-fuel mixture. |