stuck left pedal in hover: what do you do?
 

any ideas?

i found this on a website, are these the 3 ways to deal with it? "pump the collective"? anyone care to elaborate on that?

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So, today we went to our practice area and I’d bring us to a hover and then the more experienced instructor would take the controls and demonstrate a technique for dealing with this issue. He’d get us spinning left, for instance, and then show me one of three ways to fix it.

First, you can just slowly raise the collective (go straight up) and eventually you get to a point where the pedal input is balanced with the collective input and you stop spinning. Then, you slowly reduce power (throttle) and the helicopter sinks until you are on the ground softly landing.

The second method is to pump the collective. The good thing is it keeps you lower to the ground, but the bad is it kind of makes the helicopter jump up and down until you get it just right and it stops turning.

The third method you actually move the Cyclic in a circlular motion to the right at about a one foot diameter and this also will stop the spin. Again, once you stop spinning you roll off the power and you creep on to the ground. This all assumes you’re hovering.

Left turning rotor or right turning rotor? Rate of rotation? Hand throttle, throttle levers, single or two pilot?

This trick was one of my old testing officers favourites in the 300 or Robbie. It actually happened to him in a Huey once I believe.
Start a hover turn to the left... oh :mad: pedal jams.
Short verion... its a little clolurful close to the surface (depending on what sort of mood he was in) but if you catch it quickly with throttle (poor old thing flogs its guts out at the bottom of the lower arc) it spins into the wind and simply maintain direction with the twist grip whilst settling quietly with collective.
Rate of turn differed wildly on different days and it can sure give you a fright but the technique seems to work:ooh:

Assuming you are talking about an Anti clockwise spinning rotor.
Its all about restablishing the gentle balance and counter balance.

My preferred method woud be to reduce RRPM by gently rolling off the throttle while raising the collective to increase the main rotor Torque, that should balance out the increased Tail rotor thrust.
You dont want it to climb because you will start to sink with the reduced RRPM and if you are high up you could hit the ground with quite a bang.
Also you want be level and balanced when touching down, for obvious reasons.
Simple enough manouvre to grasp, worth practicing aswell, its quite easy for a small stone or something loose to lodge in the pedals of some of the older model 206's and 120's and if you are flying solo with Duals in an important peflight check that is often overlooked is to check for loose objects in the cockpit.

Rolling off the throttle to reduce the rotor RPM in increments works well - say you're in a left pedal turn, try to stop it and the pedal's stuck.

1. Don't hit anything.

2. Reduce throttle 'a bit' to achieve a particular rotor rpm drop - say 5% reduction for example. Initially, the turn will quicken due to the torque reduction, but don't panic. Hold your hover height, and as the rotor revs stabilise at the lower figure, your turn will slow due to torque being almost the same as before, but tail rotor now going slower.

3. If still turning reasonably quickly to the left, repeat step 2 as required.

4. When the turn's nearly stopped, gently lower the aircraft onto the ground. Friction on the skids will hold you once the weight's on, as long as you continue to gently wind the throttle off as the collective is lowered.

This can be practiced with an instructor, but watch your allowable power on rotor rpm limits.

The 'pumping the collective' method is more or less, getting the rotor system ahead of the governor (if installed). If you have exhausted your lower RRPM limits, or you have little or no RRPM range (in training; real emergency-what limit?), and you still find yourself turning left...

Your series of quick pulls will overpitch the machine essentially, RRPM will drop, altitude will increase and the guv will say "Wow that was fast! Heres some torque" As the nose rotates around, you quicky lower the pole, but the governor is still pouring on that last bit of torque (now excess torque, as you've flattened pitch very quicky). You will find yourself straight for a moment. Ground comes rushing up, pull again. Repeat.

By experimenting with how fast and hard you have to pump the collective, you can keep it straight and eventually work yourself lower and lower to touchdown.

The answer is sooooo aircraft dependant that there is no one solution fits all. Some of those three work on some aircraft, some of them dont work at all. For example, you cannot reduce throttle incrementally on some aircraft (EC120, AS350B3, and even 206 is hard) with enough finess, other sircraft still have enough T/R thrust at low NR to nulllify the technique (light weight B212 for example) and others are complicated by mixing unit interference dependant upon what the malfunction is and where in the control system it jammed.

Aircraft specific I'm afraid.

in the hover, in an r22

stuck right = roll off and raise. pretty simple, i understand that

stuck left = err... roll off and raise also.

i dont get how its the same procedure for both?? doesnt make sense

controller,
you will need to grab a coffee and sit down with your instructor for a half hour or so. The techniques and reasons behind your question are detailed. I will start by simplifying it this way in the hover with stuck pedal:
with power pedal forward you need to reduce RRPM/increase torque required - slowly. with non power pedal forward you need to reduce torque - roll throttle off comensurate with turn rate. cyclic into turn once on ground.

But from your question, the half hour explanation would be the way to understand this better so that you can use the knowledge later to help remind you of the overall goal and adopt techniques appropriate to aircraft type to achieve the goal.

With stuck left peddle raise collective to equalise the torque to the amount of anti torque then roll off throttle gradually to reduce RPM, hence reducing lift in the rotor system. Stuck right peddle is the opposite as in you roll off the throttle rapidly first to get rid of torque then you raise the collective to cushion the touch down, essentially a hover auto. Hope that clears it up.

I was told if you have a large left rotation quick jerk on collective to rapidly increase torque and then roll off.

"sit down with my instructor". errrr, i am the instructor!. i am going to start teaching it to students soon and wanted to try it out and get my head around it. it wasnt really covered on my PPL/CPL/CFI so hence i'm a bit in the dark about the realities of it in the r22.

thanks everyone!

I'm going to make a serious suggestion - this isn't something you should be teaching if you have never practiced/trained. Especially in the R22, the risks of inadvertant ground contact at the wrong time (with subsequent rollover a real possibility) loom large.

Get some time training with an IP who has solid experience IN THE R22 doing these maneuvers! (Just so you know, I train folks both in the R22 and 300 - working my way out of the neophyte realm with 800 hours dual given.)

You are the instructor? and it wasn't covered on your PPL? Not your CPL? And not your CFI?
And this must be a wind up.
I suggest you spend the next week doing some serious research and give ol' PPRUNE FAN #1 a call. He would love to give you a few gentle tips.....:ok:

Disclaimer: if this is not a wind up, my advice is to have your insurance all paid up, and go solo. Dont risk your student's life with your ambitions to test and develop already well understood and established techniques.


Oh yeah, after we helped you with all this advice, Can you video it for us?
:8

Sounds exactly like what Frank Robinson was trying to change when he was concerned about the accident rate for the R22 during instruction......but what would he know?;)

I still want the video......:8

this is not a windup

i know, it embarassing, it wasnt covered on my JAA PPL (gained in the UK), nor or my FAA licences (gained at HAI). dont forget its not in the FAA PTS (well, the ground knowledge is, but no requirement for flight demo)

although, an instructor did demo stuck right to me during my SFAR and i have done that with students, pretty easy. i tried the stuck left once, it wasn't pretty, hence my post.

i'm going to try to find a more experienced instructor to demo it to me.

There is another way. If you have 360 degrees of clearance then push with the cyclic. Then you can fly away and sort out the problem at 60 knots.
There have been many accidents and incidents with helicopters rotating out of apparent control in the hover. An attempt is made to land but the sucessful landing in these cases is usually only made by high time PPLs or experienced CPLs and above.
What you are trying to teach here will be forgotten in a year. It is fine for instructors to teach advanced techiniques for loss of control recovery, but let's be honest, if it happens a year later what is the chance of a student remembering the procedure?
If you fly out a tail rotor problem in the hover, then at least you have a time to sort it out, with possible assistance from an instructor/high time CPL-ATPL who has made it to the tower. You can make practice approaches to explore the controllability of the machine. If you can get to a licenced airfield the fire and emergency services will be having their first day out in months and will be right there for you.
Trying to do a quick procedure is fine for you high time guys, but for the rest of us, we need time to think, plan, rehearse and then execute these things, surrounded by all the assistance we can find.

:ooh: :ooh:

Ok fling, I was probably a bit simplistic there, let's just leave it at "fly it out."
:O :O :O

So Mr Moosp - you're saying, take the aircraft away from 5 ft above the ground where the most that could happen is a few bruises and a wrecked helo or take off into a spriralling towering take off and try to not get too dizzy while trying to get enough airspeed on to make the possibility of a fast run on landing at an airfield with a fire truck ?

Mr Selfish - I'm with yer baby !

I agree....much rather have a small crash or maybe not , from 5 foot than possibility of massive pile up !!!! Dont forget the problem may be more than just an obstruction and things could get much worse if you fly off. All in all ....a ridiculous idea !!!!:eek: Also , as i have said before, please dont keep wrecking robbies demonstrating things that almost never happen....all it does it push premiums even higher.:{