Pilot-Induced Oscillation

jesse said:
There is no hard and fast rule for recovering. A PIO does not have to be during the landing phase. It's simply the pilot over correcting back and forth making the problem worse. Sometimes it's easier to just give up and hold the stick back and wait it out. Sometimes it's better to slam power and get the hell out of there. Sometimes it's better to fix it by just not over correcting.
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Ron's suggestion may not always be the most optimum solution to PIO on landing, but IME it always will resolve the PIO. The one case where this isn't true that I can think of is in a glider (or anytime you don't have power available like an emergency landing). Pitching up protects the fragile nosewheel on a tricycle, and power keeps the plane from slowing and stalling. With a tailwheel airplane touching down in the midst of a PIO pretty much guarantees a big bounce and pitch up with power is your best hope in that case.
 
lancefisher said:
Ron's suggestion may not always be the most optimum solution to PIO on landing, but IME it always will resolve the PIO.
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I think Ron and I are saying pretty much the same thing.

lancefisher said:
Pitching up protects the fragile nosewheel on a tricycle, and power keeps the plane from slowing and stalling.
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The amount you can pitch varies with the amount of power you have. Which is what I was saying with a C150. It's not going to happen in our typical GA flying. But in the world of crop dusting it's possible to dive down and find yourself stalling if you try to level off. Pushing the nose down as you are pointed straight down is something that I guess takes some getting used to.

lancefisher said:
With a tailwheel airplane touching down in the midst of a PIO pretty much guarantees a big bounce and pitch up with power is your best hope in that case.
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I agree with that. I found out in tail wheel very quickly that it's best to get the hell out of there by pulling back and adding power. Pulling back and not adding power will probably get it under control but those might be some pretty terrifying bounces.
 
jesse said:
I think Ron and I are saying pretty much the same thing.


The amount you can pitch varies with the amount of power you have. Which is what I was saying with a C150. It's not going to happen in our typical GA flying. But in the world of crop dusting it's possible to dive down and find yourself stalling if you try to level off. Pushing the nose down as you are pointed straight down is something that I guess takes some getting used to.



I agree with that. I found out in tail wheel very quickly that it's best to get the hell out of there by pulling back and adding power. Pulling back and not adding power will probably get it under control but those might be some pretty terrifying bounces.
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I am convinced you don't understand the concept of a PIO.

Wikipedia defines PIO as:
Pilot-induced oscillation (PIO), more correctly named pilot-aircraft-coupling, occurs when the pilot of an aircraft inadvertently commands an often increasing series of corrections in opposite directions, each an attempt to cover the aircraft's reaction to the previous input with an overcorrection in the opposite direction. As such it is a coupling of the frequency of the pilot's inputs and the aircraft's own frequency.
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The reason we freeze the stick slightly aft of neutral is to stop the pilot input in the opposite direction of the plane and allow it to settle. The airplane is not the major player here. It's the pilot. That's why the procedure works for virtually every aircraft. You're just trying to stop the PIO (your opposite inputs) so you'll be in a safe position to execute a go around or land the aircraft.
 
Patch said:
I am convinced you don't understand the concept of a PIO.

Wikipedia defines PIO as:


The reason we freeze the stick slightly aft of neutral is to stop the pilot input in the opposite direction of the plane and allow it to settle. The airplane is not the major player here. It's the pilot. That's why the procedure works for virtually every aircraft. You're just trying to stop the PIO (your opposite inputs) so you'll be in a safe position to execute a go around or land the aircraft.
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I don't think you get it either. Sometimes slightly aft of neutral isn't going to be enough. In fact most of the time I'm going to go full power, and as far aft as I can possibly go without stalling it. Some other planes if I pull it aft very far it's going to climb up, stall out, and fall flat on it's face from 10 feet. That's a bad deal too.

The idea is to stop the airplane from slamming down on the nosewheel. On tail wheels it's a bad deal because you don't want to be bouncing between the mains and the tail. Things get scary damn fast. Pull back as much as you can and give it a ton of throttle. You want to go UP like now.

It's not that I'm saying that you don't want to pull back and climb out of there. I'm saying the amount of back is going to vary with every situation.

Some planes.. "slightly aft" will do a lot .. Some planes "slightly aft" will slam your nose back down and smoke the prop into the ground. But why am I arguing with you---you are an aviation god.
 
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Patch said:
I think this about sums up your maturity level.
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No..no...the maturity card..Please..not the maturity card!




Really.. I think you're just jealous of my shirt.
 
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As a CFI, I always recovered from a student's PIO by placing the stick where ever it took to establish and hold a climb attitude, while simultaneously adding full power.
 
BudRiggs said:
As a CFI, I always recovered from a student's PIO by placing the stick where ever it took to establish and hold a climb attitude, while simultaneously adding full power.
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Exactly. Whatever it takes--wherever that may be.
 
Folks, let's not make the discussion personal.
 
But is the CIA watching?
 
Yikes, that was pretty heinous. Going around would have been the approved solution.
 
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