Fan disk is the part of a turbofan jet engine that contains the fan blades. It is considered one of the most critical components of the engine and has four main functions:
- React to centrifugal loads from the fan blades - both during normal operation and during a fan blade off event
- Provide attachment from the low pressure (LP) shaft to drive the fan and to retain the fan blades
- Absorb impact loads
- Provide attachment for the nose cone and other perpherial components
Because of the critical nature of this component a fan disk failure is considered hazardous to the aircraft. They are usually made from a single titanium alloy forging.
United Airlines flight 232
, which crashed after the fan disc in its number two engine shattered and took out all hydraulic systems.