Last week, a Qantas Airbus A380 had to make an emergency landing in Singapore, after one of its Rolls-Royce Trent 900 engines exploded. Rolls-Royce has admitted there's a problem. Well, this is how the problem looks when it actually happens.
As a result of this incident, Qantas has grounded its A380 fleet for two weeks, Singapore Airlines pulled all the Trent 900s from three A380s, and Lufthansa has changed one engine from one of its mastodon planes.
But there's more than the problem that made the engine to blow up mid-flight. According to Jon Ostrower at Flight Global, "the failure in the number two engine was uncontained, as parts penetrated the wing."
This happened because the engine is not designed to contain a failure on its entirety. Only the front part can contain the engine's blades in the case of an explosion, but the rest of the casing is not designed to do so. According to the US National Transportation Safety Board, uncontained disk failure is "mitigated by designating disks as safety-critical parts, defined as the parts of an engine whose failure is likely to present a direct hazard to the aircraft."
It seems that a) their safety design principle only looks good on paper, b) Rolls-Royce has not one but two problems in the Trent 900 engine and c) the passengers and crew got lucky. [Flight Global]