Airmen Transition to Experimental or Unfamiliar Airplanes (AC 90-109)

This advisory circular (AC) provides information and guidance to owners and pilots of experimental airplanes and to flight instructors who teach in these airplanes. This information and guidance contains recommendations for training experience for pilots of experimental airplanes in a variety of groupings based on performance and handling characteristics. This AC does not address the testing of newly built experimental airplanes. The current edition of AC 90-89, Amateur-Built Aircraft and Ultralight Flight Testing Handbook, provides information on such testing. However, if a pilot is planning on participating in a flighttest program in an unfamiliar experimental airplane, this AC should be used to develop the skills and knowledge necessary to safely accomplish the test program using AC 90-89. This AC may also be useful in planning the transition to any unfamiliar fixed-wing airplanes, including typecertificated (TC) airplanes.