Test pilot :  (noun)

1: a pilot hired to fly experimental airplanes through maneuvers designed to test them

aeronaut, aeroplaner, aeroplanist, air pilot, airplanist, analyst, analyzer, assayer, astronaut, aviator, barnstormer, birdman, captain, cloud seeder, commercial pilot, copilot, crop-duster, essayer, experimenter, flier, instructor, jet jockey, licensed pilot, pilot, rainmaker, research worker, researcher, stunt flier, stunt man, test driver, tester, tryer-out, wingman,