DO-215 originally published May 1993@ was updated as DO-215A in February 1995. It offers the only currently published guidance for performance@ integrity@ and availability for data and voice over end-to-end links and their individual subsystems. New AMSS development activities in industry and government require criteria for establishing their feasibility and acceptability. DO-215A is in widespread use in those regards@ and will fill those needs until a new AMSS MASPS is available. This change provides needed clarifications and corrections required for applying DO-215A methodologies to an evolved geo-stationary satellite communications system.