Amateur-Built Aircraft and Ultralight Flight Testing Handbook
Experimental flight testing
Amateur-Built Aircraft and Ultralight Flight Testing Handbook
Active 2023 FAA handbook for developing safe, aircraft-specific flight-test plans for amateur-built aircraft, ultralights, and modified experimental light-sport aircraft.
- Publication number
- AC 90-89C
- Publisher
- Federal Aviation Administration
- Access
- Free official publication
- Best for
- Experimental flight testing
Purpose and audience
About this handbook
A structured guide to planning and conducting an incremental flight-test program while managing the risks of an unproven aircraft.
Who should use it
Builders, owners, test pilots, advisors, and operators of amateur-built aircraft, ultralights, and modified experimental light-sport aircraft.
Key subjects
What you’ll learn
Test planning and risk controls
Aircraft preparation and inspections
Flight-test cards and data collection
Envelope expansion and emergency planning
Practical study
How to use it in training
Build an aircraft-specific test plan before first flight. Use written test cards, conservative progression, defined abort criteria, and qualified assistance.
- Set an objective. Choose the chapter or topic that supports the next lesson, task, or operating decision.
- Read actively. Mark definitions, diagrams, limitations, and questions to discuss with an instructor or qualified professional.
- Apply the material. Work a scenario, calculation, briefing, simulator exercise, or supervised practical task.
- Verify current information. Check regulations, official notices, charts, and approved aircraft or equipment documents.
Edition awareness
Revision and authority notes
AC 90-89C is active FAA guidance. It does not replace operating limitations, airworthiness requirements, or aircraft-specific engineering and test expertise.
Directory review date: August 1, 2026
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