Well, it seems the thread has morphed from the very well defined topic of discussion into a US vs UK point -counterpoint debate. Lyman, on one hand, is looking for 110% perfection on jet engines introductions. OTOH, Dozy is attempting to point out that problems with jet engines go beyond national boundaries, i.e. the RR vs GE debate, a revived but standing debate. So lets look at this.
Under Lyman theory, all aircraft would be grounded tomorrow at dawn because an unexpected event, just might be a possibility, one that doesn't meet the 110% margin of safety. Sorry, the world doesn't work that way. Next time you descend into the "grassy valley" on that winding road, worry about if your car brakes will control the descent or not. It is about the same as if a modern jet engine will perform its task or not. Despite legalistic thinking, nothing is assured to 110%.
Now Dozy brings up an interesting experience at American Airlines regarding an engine that had an unusual engine vibration as reported by the crew bringing the B-767 into LAX. The amateur test theory, as applied to your car engine experiencing the same problem, would be to back it out of the garage into your driveway, and rev it up to red line, at which point, boom! That is exactly what happened at AA. They took the aircraft to a remote area, rev'd it up to red line and boom! The correct procedure was to remove the engine from the wing and perform a look-see to find a HPT disc that had a significant crack out of the dovetail slot region after all those cycles and years. This would be a cost
reduction/elimination decision to the reduce the cost of quality that went amok at AA. The result of the amok was a loss of an airplane, not to worry, the insurance folks picked up the tab.
So lets get back to the original purpose of the thread, should any new information develop...
Last edited by Jetdriver; 27th Sep 2012 at 02:26.