Let's not sensationalise them! They do send shocks through the engine- an engine designed to operate at temperatures down to -70 degrees C or colder...in severe turbulence....with ice forming on the fan blades causing vibration....to withstand the shock of landings (like mine)....with rapidly changing thrust and acceleration. If an engine cannot take the shock of a surge without damage, it should not be licensed for passenger use! I repeat what I have said before, surges are harmless. I have never known, even in a large airline like BA, a surge to result in damage. I have seen repeated surging at high reverse power for several minutes (to stop rolling), no damage done, aircraft flew quite happily next day. Early 747s were surge monsters....again harmless. They are just a backfire, and bland with it.
I take issue with the expression 'supersonic' shock waves, just shock waves will do, and I really see no connection between fan blades and Airbus fins which is a totally separate and unconnected issue! Engines can take it quite happily, just as they take the shock of startup and the explosion of fuel then every time they operate!
Last edited by Rainboe; 22nd Nov 2006 at 07:08.