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Kyle

'stuck Pedal' Caused Tense Moments

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Some thoughts on stuck-left pedals.....(i.e. too much anti-torque).

 

A tail rotor is so small that to be efficient it must spin very fast.......therefore to reduce its efficiency during a stuck-left crisis, the pilot reduces the rotor speed.....though this also reduces torque from the main rotor, that is then replaced by raising the collective....thus you have reduced anti-torque yet torque has stayed the same.

It reduces all that over-efficiency in the tail really well, like JET B was just saying.

 

But there can be a catch on some helicopters......(MD500 comes to mind).

If you reduce the rotor speed beyond a certain speed, the tail rotor blades stall and become completely inefficient !!

So you have gone from a situation with too much left pedal, to a situation with NO left pedal at all.......(and it happens really fast, trust me!!)

We all know the response to this in the hover........close the throttle.

Hopefully you are in a hover (or at least at slow speed) and above your intended landing area when all of this happens. This is why I don't like to see pilots reducing too much rotor speed until they get near their landing spot.

 

I have actually seen pilots use this idea of stalling the tail rotor to land a helicopter with a stuck-left pedal.

Rather than go through the process of slowly reducing rotor RPM, then raising collective to keep the nose straight........they simply got the helicopter to the landing site, then cut the throttle.......thus making the crisis a "loss of tail rotor" situation, rather than "stuck-left".

 

These pilots reduced rotor RPM just enough to fly the helicopter to the landing area.

They thought this technique was more expeditious, efficient and familiar to most pilots.

They also felt that some stuck-left pedals would be too far "left" to land the helicopter by just reducing rotor speed. (Imagine pulling a drill straight up out of the trees at 100% torque when your pedals stick.......sure, you punch the long-line and load off, but then you have to land with only you and 22 minutes of fuel on board......at full left pedal!!)

Also, they feel the training for new pilots is easier because students only need to learn one technique........fly the helicopter to the landing site, then cut the throttle.......regardless of the type of tail rotor crisis, (with minor variations, of course).

 

Some pilots disagree with this technique. They like to keep their perfectly good engine running, fly the aircraft to the ground, and chop the throttle only if that need arises.

What do you think ????

 

Some single-pilot helicopters have a throttle that is not a twist grip on the collective.

(I know some pilots that refuse to fly such a design).

Handling a stuck 'power-pedal' (i.e. right-pedal in this case) requires different techniques.

How do you handle your A-star in such a case????

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If I had a stuck lefty like the one in the vido clip, I would fly it to a runway or big open area and grease it down pretty much like he did. I would feel more comfortable keeping my engine on with a left pedal stuck since you always have the option of going around again if you don't like it the first time.

 

I am not a training pilot, but the way we did it with the Astars (righty pedal of course) at a company I worked for in the past: The training pilot would have you reach down and put the throttle into an NG setting that was just below required hover to power but still above ground idle WHILE ON THE GROUND. Once you had a very good feel as to where your fingers go, you could literally reach down while in the sideways flare and retard the throttle before pulling into a hover over your intended landing spot. If you did it all right, you should end up in a low rpm hover with little to no spinning and a horn blaring in your ears.

 

Now we did practice them both ways in the past, but the traditional Astar stuck pedal landings were just too hard on the skid gear for a large company to do all the time. Plus we had some pretty talented training guys who liked to try new stuff.

 

Just my opinions though, I'm just a working guy not a training guy. ;p

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Right (power pedal) in an Astar is pretty straightforward. Low slow approach, nose right, pull collective to trim while slowing down machine and just put 'er down.

 

I hate left (non-power) pedals in the Astar. Something freaky about run-on landings at 50kts... :wacko:

 

Something that always helps on stuck pedals is using wind azimuth to help. Stuck left, wind from the right. SStuck right, wind from the left...

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Thats what I was wondering about that video skidz, seems to me in training when the pedal was stuck left the keel effect helped out really well until about 15-25Kts at which point throttle was rolled off as needed but sufficient pitch to maintain flight wasn't lost until at a walking pace.

 

At that point its just a matter of being just of the ground and the 300 would settle and slide a bit. With a little bit of wind a 0/0 could be attained but it wasnt the norm.

Sounds easy! ^_^ Doing it in training is one thing but I imagine getting it done in a real emergency situation would be a bit higher stress.

 

This is really intresting reading guys, keep going. Has anyone ever had something like this in a heavy?

 

I imagine that might be alot of fun to learn in a 61 or a crane haha.

 

Cole

 

PS, this is something I've wondered about the Kamov and Kmax, I imagine the procedure for a stuck pedal would be similar in the kamov but what happens with the kmax?

 

Anyone type rated?

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Okay... now I'm really confused. Which way do the blades turn on an Enstrom anyway? :wacko:

 

Not knowing any better, I watched the video thinking his stuck left pedal was the power pedal. So..., fly it in yawed left, and as you pull power at the bottom, torque will catch up with anti-torque, and the nose should start to straighten out. The commentator in the video even said as much.

 

So how come the left yaw got even worse as the Enstrom pilot pulled pitch at the bottom? I can only assume it's because the blades are spinning the "euro" way, and he actually had a stuck non-power pedal.

 

Or maybe that's what you guys have been saying all along and I just missed it. :unsure:

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Guest JeffyG

Right (power pedal) in an Astar is pretty straightforward. Low slow approach, nose right, pull collective to trim while slowing down machine and just put 'er down.

 

I hate left (non-power) pedals in the Astar. Something freaky about run-on landings at 50kts... :wacko:

 

Something that always helps on stuck pedals is using wind azimuth to help. Stuck left, wind from the right. SStuck right, wind from the left...

 

ground track into wind.... makes remembering simple

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Okay... now I'm really confused. Which way do the blades turn on an Enstrom anyway? :wacko:

 

Not knowing any better, I watched the video thinking his stuck left pedal was the power pedal. So..., fly it in yawed left, and as you pull power at the bottom, torque will catch up with anti-torque, and the nose should start to straighten out. The commentator in the video even said as much.

 

So how come the left yaw got even worse as the Enstrom pilot pulled pitch at the bottom? I can only assume it's because the blades are spinning the "euro" way, and he actually had a stuck non-power pedal.

 

Or maybe that's what you guys have been saying all along and I just missed it. :unsure:

 

I was wondering the same thing. Stuck pedals are still something I get confused when I try to work it all out.

I guess this was a case of, as mentioned earlier in the thread, a stuck pedal waaaay left? Added torque nearing the hover simply wasn't enough to straighten it?

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The Enstrom M/R rotates the same as a Bell.

 

It looks like as the pilot slowed down he lost his keel effect, and maybe he lowered the collective as he slowed down, if he would have raised the collective the nose of the aircraft should have rotated right, it's possible that the wind was on his left hand side.

 

He did a nice job of bringing it in low enough that even if he chopped the throttle instead of over pitching it he still pulled it off.

 

Cheers.

 

Jeff

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