The most dangerous hours in an amateur-built aircraft’s life are its first ones. Phase 1 is the flight-test period the FAA assigns to every new experimental amateur-built aircraft before it can carry passengers or leave a defined test area. Handled well, it turns an unknown machine into a trusted one. Handled casually, it is where accidents cluster. This guide shows you how to plan Phase 1 so you finish it with data, not luck.
What Phase 1 Actually Is
When your aircraft gets its special airworthiness certificate, the FAA issues operating limitations that include a flight-test period, commonly 25 or 40 hours depending on engine and propeller combination. During this time you fly solo, stay inside a geographic test area, and prove the aircraft is controllable through its normal range of speeds and maneuvers. You cannot carry passengers. The point is not to log hours quickly. It is to discover problems while you are alone, high, and prepared.
Why the risk is front-loaded
A new homebuilt has never flown. Rigging can be off, fuel systems can unport in a climb, cooling can be marginal, and the pilot has zero hours in type. Every one of those unknowns is largest on day one and shrinks with each careful flight. That is the logic behind a structured test program: reduce unknowns in a deliberate order rather than all at once.
Build a Test Plan Before You Fly
The FAA’s own guidance, Advisory Circular 90-89, lays out a proven approach: fly to specific test cards, one objective at a time. A test card is a single index card or tablet page listing the goal of the flight, the sequence, target airspeeds, and abort criteria. Write them before you strap in, not in the cockpit.
Order your program from lowest to highest risk. First flights confirm basic controllability, engine temperatures, and that the aircraft trims out. Later flights expand the envelope: stalls at altitude, approach-to-landing configurations, and finally performance data. Never combine a first engine run at altitude with a first stall series. One variable per card.
Choose the Right Test Area and Airport
Pick an airport with a long runway, sparse traffic, and open terrain off both ends. You want somewhere you can make a straight-ahead forced landing after an engine failure on climbout. Avoid busy Class D fields where you are dodging traffic while managing a new engine. Fly in calm morning air. Gusty crosswinds add a variable you do not need on flight one.
A real scenario
A builder finishes an RV-style two-seater and plans a first flight on a Saturday afternoon with family watching. Winds are 12 knots gusting 18, crosswind. He is rushed and skips a full-power taxi test. On rotation the aircraft yaws hard; a rigging issue plus the crosswind nearly puts him off the runway. He aborts, shaken. The fix was free: he reschedules for 6 a.m. Sunday, does high-speed taxi runs first, and flies in dead-calm air. The aircraft flies fine. Nothing changed on the airplane. Everything changed in the plan.
Common Mistakes and How to Fix Them
- Flying an untested airplane the first time you also test yourself. If you have low time or none in type, get transition training in a similar aircraft first. Do not learn the type and the individual airframe simultaneously.
- Skipping ground testing. Do full-power static runs, fuel-flow checks in a nose-high attitude, and high-speed taxi tests before flight. Many first-flight aborts trace to problems you can find on the ground.
- No abort criteria. Decide in advance the oil temperature, CHT, or airspeed at which you land immediately. Write it on the card so you are not negotiating with yourself at altitude.
- Flying too low. Stalls and slow-flight belong at safe altitude, not on approach. Give yourself room to recover.
- Rushing to burn off hours. A sloppy 40 hours teaches less than a disciplined 40 hours flown to cards.
Phase 1 Action Checklist
- Get transition training in type or a close analog before first flight.
- Ask an EAA Flight Advisor to review your plan and your personal readiness.
- Have a Technical Counselor inspect the finished aircraft.
- Write test cards for the full program, ordered low-risk to high-risk.
- Complete static run-ups, fuel-flow checks, and high-speed taxi tests.
- Choose a quiet airport, long runway, calm air, daylight.
- Define abort limits for temps and airspeeds in writing.
- Fly solo, wear proper gear, and brief a ground observer with a phone.
- Debrief and log data after every flight; fix squawks before the next.
Conclusion and Next Step
Phase 1 rewards discipline, not bravado. Your next step is concrete: download AC 90-89 from the FAA, then call your local EAA chapter and ask for a Flight Advisor. Have that conversation before you build your first test card. The pilots who treat Phase 1 as a structured engineering task, not a milestone to rush past, are the ones who finish it with a proven airplane.
Frequently Asked Questions
Can I have someone ride along during Phase 1?
No. Standard operating limitations prohibit carrying passengers during the flight-test period. You fly solo until Phase 1 is complete and you make the required logbook endorsement.
How long is the test period?
It is set in your operating limitations, commonly 25 hours for an FAA-approved engine and propeller combination or 40 hours otherwise. Read your specific limitations, since the issuing office sets the exact terms.
Do I need special ratings to fly Phase 1?
You need at least the pilot certificate and appropriate category and class ratings to act as pilot in command of that aircraft. Beyond the legal minimum, real proficiency in type matters far more.
What if I find a serious problem mid-program?
Land, fix it, and re-verify on the ground before continuing. Do not press on with a known defect to save hours. Restart affected test cards after the repair.
Who can help me if I have never done this?
Your EAA chapter is the practical answer. The Flight Advisor and Technical Counselor programs exist specifically to help first-time builders and test pilots prepare.
References
- FAA Advisory Circular 90-89, Amateur-Built Aircraft and Ultralight Flight Testing Handbook.
- FAA Advisory Circular 20-27, Certification and Operation of Amateur-Built Aircraft.
- Experimental Aircraft Association (EAA), Flight Advisor and Technical Counselor programs.