Failure analysis of a bearing in a helicopter turbine engine due to electrical discharge damage

(in lingua inglese)

Based on the engine teardown analysis, the damage to the engine is consistent with the failure of the No. 2 bearing. Metallurgical laboratory analysis identified electrical discharge damage on the outside diameter of the number 2 bearing as well as corresponding electrical discharge damage to the bearing pocket on the diffuser plate. Additionally, electrical arc damage on the oil sling is consistent with the arc damage occurring under static conditions rather than rotation conditions.