When is the best time to discover that a new payload configuration handles poorly?

A new payload changes the aircraft's mass, its centre of gravity, its inertia and often its aerodynamic profile, and the flight controller's tuning was set for a different configuration. The result can be sluggish response, oscillation, drift, or a control loop that hunts — none of which is dangerous at three feet over open grass and all of which are dangerous at height, near a structure, or with a client watching. So the correct sequence is a low test hover in a clear area before the mission: the aircraft is close to the ground, the surroundings are empty, the pilot can observe stability, responsiveness and any unusual sound or vibration, and setting it down takes a second. Testing at altitude inverts the logic by adding fall distance and time before recovery. Reviewing recorded data afterward finds the problem only after it has already been flown, and discovering it during paid work exposes the client, the site and the schedule to a fault that a two-minute check would have caught.

A low hover in a clear area exposes handling changes while the aircraft is close to the ground with nothing nearby, so an unsatisfactory result costs nothing but the time.

Payload changes alter mass, centre of gravity, inertia and control response. A low test hover in a clear area verifies stability and handling before committing to a mission.

Three Feet Over Grass. If it flies badly there, you have lost two minutes instead of an aircraft.

Watch for drift, oscillation and unusual vibration, not just whether it lifts. Those are the signs that the tuning does not match the load.

• •Testing at altitude to have more room to recover
• •Skipping the hover for a small configuration change
• •Checking only whether it lifts rather than how it holds