This advisory circular (AC) sets forth suggestions and safety related recommendations to assist amateur and ultralight builders in developing individualized aircraft flight test plans. The Federal Aviation Administration (FAA), the Experimental Aircraft Association (EAA), and the United States Ultralight Association (USUA) are concerned and committed to improving the safety record of amateur-built and ultralight aircraft. The FAA Administrator, T. Allen McArtor, and EAA President, Paul H. Poberezny, signed a Memorandum of Agreement on August 1, 1988, which addressed the need for educational and safety programs to assist amateur-builders in test flying their aircraft. In accordance with that agreement, this AC provides guidelines for flight testing amateur built aircraft. As part of the FAA's continuing efforts to improve the safety record of all types of general aviation aircraft, this AC has been revised to include flight testing recommendations for canard-type and ultralight aircraft. This AC's purpose is the following: (1) To make amateur-built/ultralight aircraft pilots aware that test flying an aircraft is a critical undertaking, which should be approached with thorough planning, skill, and common sense. (2) To provide recommendations and suggestions that can be combined with other sources on test flying (e.g., the aircraft plan/kit manufacturer's flight testing instructions, other flight testing data). This will assist the amateur/ultralight owner to develop a detailed flight test plan, tailored for their aircraft and resources. The flight test plan is the heart of all professional flight testing. The plan should account for every hour spent in the flight test phase and should be adhered to with the same respect for the unknown that all successful test pilots share. The time allotted for each phase of a personalized flight test plan may vary, and each phase may have more events or checks than suggested in this AC. The goals, however, should be the same. The two goals for an amateur builder/ ultralight owner should be as follows: (1) At the end of the aircraft's flight test phase, the aircraft will have been adequately tested and found airworthy and safe to operate within its established operational envelope. (2) Incorporation of the flight test operational and performance data into the aircraft's flight manual so the pilot can reference the data prior to each flight.