Persons designated by the Administrator as check airman for the air operator under the provisions of FAR 121.401(a)(4), FAR 135.323(a)(4) or FAR 125.295.  Do not include persons in a training center authorized under the provisions of FAR 142.55(a).
A check airman is a person who is qualified to conduct flight checks in an aircraft, in a flight simulator, or in a flight training device for a particular type aircraft.
A check airman must, with respect to the aircraft type involved,
(1) Hold the airman certificates and ratings required to serve as a pilot in command in operations;
(2) Have satisfactorily completed the training phases for the aircraft, including recurrent training, that are required to serve as a pilot in command in operations;
(3) Have satisfactorily completed the proficiency or competency checks that are required to serve as a pilot in command in operations;
(4) Have satisfactorily completed the applicable training requirements;
(5) Hold at least a Class III medical certificate unless serving as a required crew member, in which case holds a Class I or Class II medical certificate as appropriate;
(6) Have satisfied the recency of experience requirements; and
(7) Have been approved by the Administrator for the check airman duties involved.