Output shaft air/oil separator to redundantly protect against output shaft o-ring leakage

An air turbine starter, comprising:

• an outer housing;
• an oil passage disposed in the outer housing and having an outlet port;
• a spline shaft having a first end, a second end, an outer surface, and an inner surface defining a cavity extending between the first and second ends, the cavity in communication with the oil passage outlet port;
• an output shaft disposed at least partially within the spline shaft cavity, the output shaft having an outer surface including a first section and a second section, the first section spaced apart from the spline shaft inner surface to form a gap therebetween in communication with the spline shaft cavity, and the second section contacting at least a portion of the spline shaft inner surface;
• a bearing assembly mounted to at least a portion of the spline shaft outer surface;
• a bearing cavity defined by the bearing assembly and the spline shaft outer surface;
• a housing cavity defined by at least a portion of the spline shaft outer surface and the outer housing;
• an annular groove formed in the spline shaft outer surface in communication with the spline shaft cavity;
• a first port extending between the spline shaft inner and outer surfaces and having an inlet in communication with the annular groove and an outlet in communication with the housing cavity;
• and a second port extending between the spline shaft inner and outer surfaces and having an inlet in communication with the spline shaft cavity and an outlet in communication with the bearing cavity.