Pilot Induced Oscillation (PIO)

[RV_7A]

Anyone experience this problem and what did you do? Would you say there is a fine line between recovery by adding power depending on your speed once power is applied? Anyone bend or break gear on their RV? Prop strike? etc? Inquiring minds need to know...

-Jeff

[Mel]

I have never experienced PIO in an RV. I did experience it in a Moni motorglider. I was at the extreme aft end of the CG range during the flight testing phase. The problem with PIO is that as by definition, the pilot is causing it by "chasing" pitch with the elevator. The cure is to STOP chasing and hold the stick rigid. the aircraft will then stop oscillating. Power will NOT help.

[RVPilotDotCom]

Mel... right on target. If you have enough runway, you can keep that stick steady, until all that energy bleeds off and down you will settle.

Fact is, PIO are created by forcing the plane to land before it has lost enough energy to do it on it's own. If you are bouncing down the runway it's because your plane wants to keep flying.

If you pull back easy on that stick and your still three feet off the runway at the mid point, you might want to consider doing a go-around. Either that or pull the drag chute ;-)

- Jim

[fliier]

I did experience this in a 6A at about 250 hours.

Initially I attempted to salvage the landing. After the first bounce each subsequent oscillation grew progressively more severe and steep. On the last one the entire windshield seemed to be filled with pavement. I finally added power, had one more light bounce, and went around.

The incident was sufficiently severe for me to remove the gear leg and have it magna-fluxed. I also had to rebuild the front of the nose-gear wheelpant which had been severely abraded. You can take a look at a -6A nosegear to understand the required geometry.

Having gone through the experience I would never again attempt to salvage a landing like that unless absolutely necessary.

FWIW, there was nothing unusual about the approach. Winds were light off the nose. I had never experienced a similar problem in the couple of hundred landings before, or in any since. A thorough post-flight inspection revealed nothing wrong with the plane, which leads to the only logical conclusion being the pilot.


John Allen