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landing-stuck(left-right)pedal for h300


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land helicopter as soon as possible.... confusion over

 

ok.. really, has anyone ever had a stuck left or right pedal in the 300? The only real possibility I can ever imagine is the control cable breaking which would render the pedals useless and the t/r at a neutral angle...but regardless...too lazy to write it all down... Pretty sure if you search... someone else has written this before on here.

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(The following is for discussion only, and should not be attempted without appropriate supervision) I would also consult the RFM to see what the manufacture's recommendation is.

 

The following is regarding fixed pitch in forward flight (hovering is a different animal and generally a different problem):

 

The way I look at it, you are dealing with a fixed amount of anti torque that needs to be matched with the appropriate torque. So how do you do that?

 

I'd say find a runway with favorable winds. So, if you have insufficient left pedal to hover, you would then have a stuck "right" pedal. Keeping in mind, it is very difficult to have a stuck negative pitch in the tail rotor, so in general you will more than likely have some thrust from the tail rotor. Broken bell cranks and such might result in neutral pitch. Having said that most instances of stuck controls result from debris in the cockpit. The general tendency is to look for a crosswind opposite the "pedal" that is stuck.

 

I make an attempt to cross the threshold of my choice at Vy or slightly over, and in level flight within close proximity to the ground. Say 10-15 feet. This way you are at the lowest torque possible with no rate of decent to arrest. Then use whatever length of the runway I might need to slow the aircraft down to the point of equilibrium. Balanced torque vs anti torque. It is at this point a decision needs to be made. Can I satisfactorily touch the aircraft down at this ground speed. If I can, simply stab forward on the cyclic to lose lift and run it on. Others, may suggest rolling the throttle off if you need to keep your nose aligned with your ground track, but that can be very dicey. Another option is to let the nose of the aircraft rotate past your ground track and flare sideways a bit, via a quick stop, and roll off the throttle as the collective is being raised to cushion the set down. The helicopter can usually be stopped this way, without forward movement, but it needs to be a well coordinated throttle roll and collective raise. Your nose will not be facing the original direction.

 

There are other methods, but some leave you with only one attempt. IE, a steep approach to minimize torque with an autorotative landing. it is difficult to go around in that profile. Making your approach long, shallow and at Vy allows you the opportunity to accelerate again if you need to go around and attempt a second time.

 

Having said all that, it is a relatively uncommon failure. Bell did a study a while back and found that most stuck pedal accidents occurred in stuck pedal training.

 

A good foundation of knowing the effects of controls, make dissecting this and most other emergency procedures much easier. If you know instinctively which way the nose will rotate by raising and lowering the collective you are ahead of the curve.

Edited by C of G
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Here is what I have to share about stuck pedal maneuvers in a H269C1:

 

First of all you have to differentiate between a training situation and the real world flying.

The way I trained this maneuver is bascially that it requires you to understand aerodynamics of a helicopter. Meaning what effect do ground effect, airspeed, weight, wind direction and Rotor RPM have on the yawing.

 

In the real world flying you should be able to take all this factors into account and create your own scenario that will bring you down safely.

In general my philosophy is: train to the highest standards possible and you will have that safety margin you will be able to use in the real world.

So people can argue that all this I am describing is not necessary but I am convinced understanding it to that extent will give you a safety margin and that's what it's all about.

 

The second differentiation you would have to make is: what kind of stuck pedal situation do I have?

Generally you can say there is

1. High Power stuck pedal

2. Low Power stuck pedal

 

Let's start with High Power

 

In this scenario your pedal gets stuck in a high power setting, let's say while in a hover or a climb out where you usually would counteract the amount of power you are pulling by a left pedal input. Lets say for the sake of argument anything above 20 inch MAP can be considered a high power scenario.

 

Now Low Power

 

In this scenario your pedal gets stuck in a low power setting, let's say in a slow cruise flight or descent where your counteraction would be a right pedal input to compensate left yaw. Let's say anything below 20 inch MAP can be considered a low power scenario

 

Now here is how I am going about it. And remember it's about the safety margin and it is a training exercise:

 

First I want to find out what kind of stuck pedal situation I have.

Here is a procedure to find this out: In cruise flight you lower the collective so your trim ball is right off center, you reduce airspeed to 40 kts and maintain altitude.

In order to maintain altitude you will have to pull power again. But watch the trim ball: once it is centered try to maintain this attitude (power, RPM, speed and altitude) for a moment. And note the power required for this situation. Let's say it is 22 inch MAP. That tells you you will have to deal with a high power scenario as defined above.

Or in other words: you can pull 22 inch MAP power at 40 kts and your trim ball will be centered. And you know this check is done out of OGE. So IGE you know that you will be able to pull less power and therefore be able to fly at less airspeed with the trim ball centered. Here is your first safety margin. So now you continue the approach which will be a shallow one. Because in this maneuver you do not want to have any sudden control inputs. Once you turn final try to get your parameters, as long as you are at or above 40 kts and at or below 22 inch MAP your nose will be centered or left off center.

Now let the ship descend into ground effect and you will notice the nose will go more to the left, which is good. Now you should only change one parameter at a time and watch what the ship is doing. So let's slow down the descent rate and pull some power and maintain the airspeed (remember maximum power you can pull is 22 in MAP at 40 kts OGE). This will create a right yaw, which you will have to watch closely, you do not want the nose to turn further to the right then12 o'clock (12 o'clock = centerline). What you do in case the nose is turning through your 12 o'clock I will explain later. But for now you should make sure your nose is at or left off center. As you are coming into IGE let's change the next parameter: air speed. As you reduce air speed your nose will turn to the right (a wind direction from the left will slow this down or avoid this) Again watch your nose: do not slow down the ship too much to avoid a turn to the right over your 12 o'clock. As you have stabilized this you can reduce power again, the nose will go to the left or stop turning to the right. So now you change air speed and power until you have reached your landing strip. As you lower collective for touch down you will have to be able to slow down even further. If you do this procedure you will be able to set this thing down with the nose straight ahead at minimum airspeed.

 

So now what do you do if the nose yaws through your 12 o'clock to the right? This situation has to be watched closely. You know now that you need higher airspeed in order to get the nose straight ahead again or to lower the power to induce a left yaw back to 12 o'clock or further to the left.

As you might not have the altitude left to reduce power IGE your only option may be to increase airspeed. But increasing airspeed means pulling more power and worsening your right yaw which could built up a pretty fast right yaw. So you should be alerted if the nose is approaching the 12 o'clock position from the left and the yaw rate is not slowing down or stopping at or before 12 o'clock. So when you are training this and the nose is accelerating to the right abort the maneuver if you do not feel comfortable to recover it.

 

For the low power scenario pretty much the same procedure applies. Once you are in ground effect you will notice you need a higher air speed to maintain nose left off or at center. So at the end the air speed at touch down will be higher.

 

And if you have mastered this procedure you will touch down at a constant RPM.

 

Now to the real world flying:

 

You still should find out what scenario you are dealing with and you might be able to fly it all the way to the ground like described above. But here are some tips and tricks you can add to your tool box:

 

Wind:

Always try to get the wind from the left. Wind from the left is your substitute for your left pedal, wind from the left is your friend. If this requires not to fly aligned with the centerline of the runway, do it. This should be general knowledge. If your instructor does not teach you this, change the instructor or flight school….;-)

 

RPM:

In the section above I did not say a single word about rotor RPM. The reason is if you are able to fly the maneuver above you still have the safety margin of rotor RPM. And why use it if you do not need it?

But in case landing is assured you can also use the throttle to manipulate rotor RPM to maintain the nose straight ahead for touch down.

Here is a little trick, because I could never remember what throttle closing/opening does to the nose of the helicopter. Oh yes, on the ground when I am sitting at my desk I do. But in the air it seems to me that some parts of the brain just do not function right….anyway back to business.

Look at your collective hand and stretch out your index finger.

Then imagine you open the throttle. Where is your index finger pointing? To the right. Close the throttle and it will point to the left. This is exactly what the nose will do.

So take this to the next level and you will understand that in a low power setting (nose to the right) you want to be at the higher end of the RPM limit.

 

Weight:

In the H269 the only weight you can play with is fuel. If you are at minimum fuel do not play around burning off fuel.

If you are at full tanks you might consider this as an option.

Generally you can say burning off fuel in a high power setting scenario is an option in a low power scenario it might worsen the right yaw requiring an even higher airspeed for touch down.

 

And after you declared emergency and request the biggest runway at an airport and the fireguards setting up shop and EMS crews are lining up they might be surprised that what is an emergency for you looks like a perfect landing to them….

 

Try this with your favourite instructor. This might become your favourite maneuver…

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