Originally Posted by
henra
May I remind you of these words once the final report is out?
Those cowlings are only thin covers. Underneath is the massive structure designed to contain fan/turbine blades in case of separation.
The cowling material will probably tear away and the structure underneath will remain circular. I don't think what we see in those pictures contradicts a contact with the runway. Anyway the final report will tell us the truth.
the black marks on the side towards the rear of the cowlings have not necessarily contacted the tarmac itself. That could be sooting from the heat or oil stain.
The structure at the bottom of the engine isn't "massive" relative to the weight and speed of the airplane. The transfer gearbox and the low end of the accessory gearbox are at or very near the bottom center line. The cowls are light weight structure not sized to support the airplane without damage. If you scrape the engines significantly you are likely to put holes in the accessory and transfer gearboxes, and will very quickly lose the engine oil. Bearing failure will then follow quickly if high power is commanded.
The regulatory requirements are for such an event are intended simply to not breach the fuel system for crash safety reasons (see 14 CFR 25.994).
Sec. 25.994
Fuel system components.
Fuel system components in an engine nacelle or in the fuselage must be protected from damage that could result in spillage of enough fuel to constitute a fire hazard as a result of a wheels-up landing on a paved runway under each of the conditions prescribed in § 25.721(b).
The requirements and design intent have never been to maintain ability to continue running the engine at high power following such a scrape event. They are simply intended to prevent post-crash fire in a wheels up controlled landing.