4. Foreign Object Damage (F.O.D)
Hard foreign object – compressor
This damage is caused by a foreign object entering the compressor. The object may bounce around in the compressor inlet.
Salt or sand causes sever erosion and corrosion eventually leading to blade failures.
Soft Foreign Object
Soft foreign objects such as workshop cloths or even paper wipes can cause damage. Typically, the blades bend backwards and in extreme cases sections of the blade may break way due to metal fatigue.
Hard Foreign Object – Turbine
A hard foreign object entering the turbine will damage the inducer (inlet) blades. Even small objects such as rust scale (from the exhaust manifold) can cause considerable damage to such high speed components.
