Pilot Induced Oscillations

Lesson Objective

It is common for new pilots to experience Pilot-Induced Oscillations, usually in the pitch axis.  The PIO can happen in any phase of flight, but the most dangerous is in the final moments of flight, or during the ground roll-out.  The instructor will discuss strategies with the student on minimizing the probability of having a high-energy landing turn into a PIO that can damage the tail boom. 

Regulatory Requirement

none

Content

• Pilot Induced Oscillations on Launch (pitch)
• Pilot Induced Oscillations on Landing (pitch)
• Pilot Induced Oscillations in flight (dutch roll)
• PIO prevention strategies
• Forcing the glider back onto the runway at too high of a speed
• Minimum energy landing strategies

Completion Standards

The candidate must be able to consistently land the glider at minimum energy (with spoilers deployed).

For the ASK-21 trainers, our club instructors emphasize the two-point landing technique: tail wheel and main wheel landing simultaneously. The "fly-it-on" landing strategy is highly discouraged for these gliders, although note that it is appropriate for this technique when landing Schweizer gliders. 

Prerequisite Study

• Glider Flying Handbook (2013), Chapter 8, Pilot-Induced Oscillations, page 8-2
• http://www.soaringsafety.org/briefings/grobpio.html Soaring Safety Foundation article on landing PIO.
• http://tinyurl.com/Glider-PIO Video clip of student landing (too fast) in Grob-103, which turns into PIO.  Review this with an instructor!  Also https://www.youtube.com/embed/cX4oFDEKm94