Helicopter rotor containment specification

It's sort of like the Air Force — or maybe Army; the government tends to share these specs — has a spec that you have to have a shell around the engine compartment for the turbine on a helicopter that will contain the rotor if there's a rotor failure, so it won't go through the pilot's compartment and cut him in two. He doesn't fly as well when he's cut in two. They've done studies on this — probably very expensive studies — and there is no material that can stop a rotor from going through. Well, there are materials, but you're talking about armor. If you want to put two-inch armor plate around your engine, that's fine; you just can't get your helicopter off the ground. The FAA has adopted the standard, but no one can meet the standard, so everyone ignores the standard. It's like the Navy's humidity requirement for welding in shipyards. You just ignore the standard, because otherwise you couldn't do anything. You get certain groups of people who develop standards or ideas, and they don't look at the practical reality.