Flight testing a home-built aircraft is the most dangerous activity in this reference, because the first flight of a new design is the most dangerous flight it will ever make and it is flown by a person who built it. Proof-load the structure first, be trained to fly in a sound aircraft before touching the controls of an untried one, and then advance in steps, ground handling, taxi, short hops, low tows, each step only after the last has been survived and the aircraft inspected. Any unexpected behaviour ends the day.
Part of Aerodynamics and Flight
The order and the conditions under which an untried aircraft is first flown, and why the order exists.
Why This Kills Experienced People
Test flying kills trained pilots with good equipment. Designers and builders can be wrong in ways that appear only in the air: a control that flutters at a speed nobody reached before, a stall that rolls the aircraft over, a centre of gravity that was never right, a spar that was never strong enough. A pilot cannot recover from most of these. The home-built aircraft from salvaged material, flown by someone who learned from a reference wiki, is a lethal combination, and this article says so without softening it.
If a surviving aircraft, or a surviving person who flies, exists in your area, that is a safer route to flight than building a new one. Construction is a late undertaking, after the materials base can supply timber, glue and metal of known properties.
Gates Before Any Flight
- Structure: the spar and fittings are calculated with measured material properties and the wing is proof-loaded (Structural Spars, Ground Testing). A structure not proven should not carry a person.
- Pilot: trained, in a known sound aircraft, by someone who can fly. A reference cannot give the judgement for a first stall or a first landing. Without it, do not be the test pilot.
- Aircraft: weighed, centre of gravity inside limits, controls checked by a second person, engine run, tie-down thrust measured.
- Site: long, flat, clear on every side, with a place to land ahead after an engine failure.
- Weather: calm. The carrier says wind under 15 km/h with no gusts; early morning or evening is often calm.
- People: ground crew who know their roles, first aid and a fire extinguisher at hand (Bleeding Control, Fracture Repair, Shock Treatment).
- Plan: a written plan, including what ends the test (stop criteria).
The Progression And Why It Is In This Order
Ground handling and control checks come first (Ground Testing), then unpowered flight as a glider, hops in ground effect, and low tows (Glider Testing, Tow Launches), with powered flights only after those. The point of each stage is that the next is small: an error at a low height is a bruise; at higher speed or height it is a funeral. Increase the envelope slowly (Envelope Expansion).
Rules For The Test Day
- One change at a time, between flights.
- A written log of every flight: date, wind, weight, centre of gravity, what was done, what was seen.
- Stop at the first surprise. Do the inspection, find the cause, fix it and start again from an earlier step.
- No spectators near the runway.
- No pressure. Postponing is free; flying on a bad day is not.
Common Mistakes
- Skipping steps because the previous one went well.
- Testing alone.
- Flying with a known fault.
- Believing the calculation covers what was not built as drawn.
Safety
This activity kills
Structural failure in flight cannot be survived; a stall at low height cannot be recovered; a tow that cannot be released or a rope that breaks at low height can end in a stall. Do not attempt a first flight of an unproven aircraft without proof-loading, training and a stepwise plan. If any of those is missing, do not fly.
What’s Next
- Learn next: Ground Testing, the first step
- Combine with: Flight Instruments, what you will read