http://www.dailyrecord.co.uk/entertainment/celebrity/bewitched-hogans-heroes-tv-star-9461533 The bumbling Colonel (Group Captain) Crittenden is gone. I guess this only leaves LeBeau and Baker.
His uniform was that of a Group Captain. Everyone referred to him as "Colonel" (Group Captain is equivilant to a USAAF Colonel), presumably to make him more of the comedic antithesis of Colonel Hogan.
He was often good for a laugh and frequently played the bumbling officer as I recall. Occasionally played the serious role, but I suppose from seeing play comedy so much it seemed off some how.