Pilot-Induced Oscillation (PIO) in a Gyroplane

Pilot-Induced Oscillation (PIO), also known as porpoising, occurs when a pilot unintentionally causes the gyroplane to pitch repeatedly up and down through excessive or poorly timed control inputs.

Rather than correcting the aircraft's attitude, the pilot's inputs cause the oscillations to continue or become progressively worse.

Contributing Factors

Several factors can increase the likelihood of PIO:

• Excessive control inputs – Overcorrecting with forward or aft stick movements.

• Delayed reactions – Applying further corrections before the gyroplane has responded to the previous input.

• High airspeed or turbulence – Increased control sensitivity and gusts can make it easier to overcontrol the gyroplane.

• Light control forces – Sensitive controls can encourage excessive stick movements.

• Pilot inexperience – Unfamiliarity with the gyroplane's response to control inputs.

Control Response Lag

When the pilot moves the control stick, the rotor disk tilts, but the gyroplane's fuselage does not immediately follow.

The fuselage hangs beneath the rotor like a pendulum and, due to its inertia, takes time to respond to changes in the rotor's attitude.