Definition
A turbine engine failure in which high-energy rotating parts -- typically fan, compressor, or turbine disk fragments -- break free and penetrate the engine case, escaping the engine entirely. Because the engine housing is not designed to stop disk fragments at full rotational speed, the released debris can strike the airframe, fuel tanks, hydraulic lines, control systems, or the cabin.
Plain English
A serious engine failure where pieces of the spinning internals break loose and punch through the outside of the engine instead of staying inside it.
Context Anchor
Seen in turbine engine emergency discussions, accident reports, and training about severe engine damage.
Derivation
Uncontained means 'not held within.' The engine case is built to contain the debris from most failures (a contained failure). When fragments escape the case, the failure is uncontained.
Why Pilots Care
Fragments can sever fuel lines, damage flight controls, or start fires, often forcing an immediate emergency landing.
Grounding Statement
Picture a fast-spinning metal part inside the engine breaking loose and punching through the engine cover.
Intuition Check
Uncontained does not just mean the engine problem is severe or hard to control. It means pieces physically escaped from inside the engine.
Example Sentence 1
The crew declared an emergency after an uncontained engine failure sent debris through the wing.
Example Sentence 2
Post-incident inspection confirmed an uncontained engine failure when turbine blades were found embedded in the wing.