Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 65; Flight Crew Total 6700; Flight Crew Type 55
Distraction; Situational Awareness
Airspace Violation All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural FAR
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Became Reoriented
Human Factors
DOD Contract Mission supporting military training and was enroute to the ZZZ MOA operating under public use. Aircraft X cleared on heading 350 and descended to FL190 to enter the ZZZ MOA at altitude. Traffic called out off the nose opposite direction FL200 Aircraft Y. Center queried Aircraft X on altitude. Pilot glanced at altimeter and noted 19;140 and the response from Aircraft X was; '19.1 correcting.' Pilot was given a phone number to call with Center upon landing regarding a possible pilot deviation. Upon further discussion with the Center supervisor; Center indicated a loss of separation 700 ft/3.9 NM between Aircraft X and an Aircraft Y. Review of the aircraft Garmin recorded altitude data indicated an altitude of 19;235 MSL at [time] (approximately 7 seconds before the reported loss of separation) with an altitude of 19;181 ft at the Center time of separation loss. Pilot human performance considerations include simultaneous discussing weather (frequency management) for the mission on the other radio; potentially taking scan away from direct altitude scan while also transitioning pilot's visual lookout externally to pick up the Aircraft Y opposite direction traffic. Lack of autopilot / altitude hold mode was a contributing factor but not a substitute for basic air work altitude hold at FL290.
Military pilot reported an airborne conflict with opposite direction UAV.