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StanFoster

Confined area takeoff

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I received my helicopter rating in an R22 last October. My instructor taught me to do my confined area takeoffs as in this video. I just made this video this morning in my Helicyle....clearing those 70 foot tall trees 200 feet away. I was taught to use as much room as I have of course...lift off and pull max manifold and establish and angle that clears the trees by a little bit. My instructor and I flew this exact flight in the R22 loaded to near gross..flew the same angle but it was a lot slower getting out of there.

 

Question to anyone. I had another instructor see this video....and he told me that he would take off vertically till I was at treetop height...then go horizonantally and transition through TL and depart that way. I told him if I had done that on my checkride...I bet I would have failed. So, I am a fledgling pilot wanting to know your opinions on if you would do it the way I did it in my video, or would you go vertical like the other instuctor told me. I know I am toast either way with an engine out...but the instructor advising me against the way I did it says I would at least crash in the clearing without eating trees.

 

 

Stan

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I was doing my BFR with Jerry Trimble earlier this year and did a MPTO just like I was taught: go from the surface, straight straight straigh up until clear the obstacle, then nose over and go. As I was announcing my intentions ("...15V, vertical takeoff from 21...") Jerry laughed "Optimist!" When I was done, he went through a demo of the difference in power that it takes if you just go vertical (my way), vs if you use any little bit of forward movement. I can't remember numbers, but we needed much less power to climb vertically if we had any forward movement (not even ETL).

 

We then went into a confined area--nothing too tight, but much tighter than in your video--and put his method to practice. It works. His whole point was "why would you do a vertical takeoff if you have even a little room to get airspeed?" Airspeed = >performance and

 

My thoughts. I'm sure others will be able to explain it better.

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...Question to anyone. I had another instructor see this video....and he told me that he would take off vertically till I was at treetop height...then go horizonantally and transition through TL and depart that way. I told him if I had done that on my checkride...I bet I would have failed...

 

On my Private check ride, the DPE said "don't go straite up", so I pushed forward a bit. :mellow:

 

On my Commercial check ride the DPE said "no forward movement allowed", so I went straite up. :blink:

 

Over the years I have found that every Cfi, or DPE, has their own interpretation of various maneuvers. <_< So, when flying with them, do what they want, then when you're by yourself, do what you think is right!

:)

 

Having just seen Kodoz's post, I agree. If you have room, use it, but remember, sometimes you won't, and you'll have to go straite up.

Edited by r22butters

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good point kodoz, and this discussion will stir up discussions to argue both methods. In my opinion, neither are right or wrong. just different methods for different situations.

 

What if you fly EMS? A vertical takeoff could be seen as more safe in the event of an engine failure. What happens if you are moving forward and barely clear your obstacle and the engine quits? Maybe you just put your helicopter into the roof of a building and caused some fatalities. Same situation, but limited power, and you start to settle, now you have to flare to stop that forward airspeed and risk hitting your tailboom.

 

I, and everyone else, will be able to come up with scenarios to argue both ways. I think the correct answer is that neither are wrong, just one may be better for different situations. I prefer vertical if I have to power.

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The way you did your take off in this case is the same way I would have. Uses less power since you have forward speed. Also, allows you to get your speed and altitude up and out of the HV curve. There is a forced landing area just beyond the trees you climb out over. Looks fine to me.

 

Now, having said that, not every situation is the same. in some cases a vertical or near vertical take off profile will be better. In EMS this is even more true. That is because we have never landed at the location we are called out to most of the time. As a result everything has to be slower and steeper both going in and out. Wires can be hard to see and many times the First Responders miss them.

 

It all depends on the situation you are presented with. The thing to look at is the risk vs reward. In your case, it's your property, you've been there many times and know where the obstructions are. You have the room for some forward speed and forced landing areas ahead of you. So, no reason for a vertical take off in this case.

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I've been taught both. My personal policy is the same as those who have already posted. If you have room, use it. I got to do some flying this spring with an Ag pilot who showed me some real world situations. We simulated a VERY confined area with limited power that involved a straight up climb to clear a very real, very tall tree. About 85 feet of tree, actually. We pulled all the power allowed for that exercise, and when we stopped climbing, merely had to wait a while before it began to climb. The climb was painfully slow, but it did the trick.

 

My commercial DPE mentioned using this same tactic while flying EMS to get a very beefy pax above some powerlines.

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The "go at an angle to just clear the trees" method is the one we used in the Army flying Hueys that were overloaded. That's the method that takes the least power and will get you out most of the time. An engine failure on takeoff will almost certainly result in bent metal, but sometimes you take the lesser of the many evils. If you're worried about engine failure, and about wires being in the way, then straight up above the obstacles and then away is the way to go, but having an engine failure at max power and 80'AGL in a hover isn't a lot of fun either. The method I use depends on the situation, and one isn't always the best. I usually make a decision based mainly on the likelihood of wires being in the way, unseen. Judgement is always necessary when flying a helicopter. On a checkride, you do whatever is necessary to pass the checkride. Checkrides and the real world have little to do with each other.

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The most difficult trap of all hasn't been mentioned: What do you do if you commit to the "Angle that minimally clears obstacles" and don't have the power to do so? That's about a million times more likely than a straight engine failure. That really puts you between the rock and a hard place- Do you pull what you need and write it up (Hope you you got the power and the integrity to document your mis-judgement). Or, do you abort from a really crappy position, out of ground effect with your cleared area behind you and at your power limit?

 

The vertical departure has issues to consider, too. It's very hard to do a pure vertical if you don't do a lot of'em, especially a long, slow climb. To me, the scariest thing is a possible drift to the rear, I can't see back there, so the first thing I know I've got "trimmings" flying around and a lot of noise- if I don't knock the tail rotor right off.

 

As previously mentioned, this is a judgement call each and every time. Use what you got but know the gotchas in each. I HATE looking at the tree/building/mountain getting close, knowing I have to torque turn and try not to scratch paint.

 

Me, I'm going to do a power check, look at the PROPOSED landing site, departures, and decide before I land, while I have options.

 

And, probably vertical out...

Edited by Wally
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The most difficult trap of all hasn't been mentioned: What do you do if you commit to the "Angle that minimally clears obstacles" and don't have the power to do so? That's about a million times more likely than a straight engine failure. That really puts you between the rock and a hard place- Do you pull what you need and write it up (Hope you you got the power and the integrity to document your mis-judgement). Or, do you abort from a really crappy position, out of ground effect with your cleared area behind you and at your power limit?

 

The vertical departure has issues to consider, too. It's very hard to do a pure vertical if you don't do a lot of'em, especially a long, slow climb. To me, the scariest thing is a possible drift to the rear, I can't see back there, so the first thing I know I've got "trimmings" flying around and a lot of noise- if I don't knock the tail rotor right off...

 

Once during my Commercial training, my instructor asked that very question just before a max-takeoff from a confined area. I didn't know, so he said, "just go back down".

 

Then we proceeded with the takeoff. Upon reaching the top of the trees, he rolled the throttle down. When the low-rpm horn went off, I simply lowered the collective, and backed my way back to the LZ. I already knew what was behind me (since I had just been there), so no problem. :)

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Upon reaching the top of the trees, he rolled the throttle down. When the low-rpm horn went off, I simply lowered the collective, and backed my way back to the LZ. I already knew what was behind me (since I had just been there), so no problem. :)

 

Wow, you had an instructor actually do that? I've only done it as a thought experiment--as I was reading Wally's post, I was thinking about a sit-down MikeMV and I had where this was one of the techniques we discussed.

 

I want to ask something that I think probably qualifies as one of those rules of thumb. Don't know the validity of it, but I was once told: "If you can see blue between your tip-path plane and the obstacle, you can make the take-off." This isn't about power, it's just about angle. The way my instructors would put this to play was to climb vertically until you could see that separation, then start moving forward. Thoughts?

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Then we proceeded with the takeoff. Upon reaching the top of the trees, he rolled the throttle down. When the low-rpm horn went off, I simply lowered the collective, and backed my way back to the LZ. I already knew what was behind me (since I had just been there), so no problem.

 

I don't think I would ever roll the throttle down in this situation but maybe give a manifold pressure limit and not allow the student to use any more than that.

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Once during my Commercial training, my instructor asked that very question just before a max-takeoff from a confined area. I didn't know, so he said, "just go back down".

 

The problem with that is that your takeoff was most likely into wind (if there was any wind in the hole).

You are now going backwards, at max power, downwind, into a confined area. You immediately lose whatever translational lift you had and your ROD might very well increase more than you want in this situation.

 

I'm not saying that this method is generally wrong, I'm just saying, a vertical takeoff is MUCH easier to abort.

 

If you are unsure about power, why not try to go vertical to find out how high you can get and thus get an accurate idea about your power limitations.

 

You can then go back down (vertical) and take off at an angle if you want, or continue the towering takeoff - or abandon the whole thing and walk home if you have to.

Edited by lelebebbel
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I like this one, seems really sensible:

 

If you are unsure about power, why not try to go vertical to find out how high you can get and thus get an accurate idea about your power limitations.

 

You can then go back down (vertical) and take off at an angle if you want, or continue the towering takeoff - or abandon the whole thing and walk home if you have to.

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Lele, Good post and I agree with your entire post in theory and for safety reasons other than this statement "You are now going backwards, at max power, downwind, into a confined area. You immediately lose whatever translational lift you had and your ROD might very well increase more than you want in this situation."

 

Let me analyze this, yes we are backing down(at a slow rate) but still facing into the wind with a reduced collective and full rotor RPM so ROD is not a factor. You had power to climb to that position, so terminating back at your point of departure is really simple if you had a return plan prior to initiation. And really, we have not departed the confined area(that is the problem we are addressing)

 

The backdown is not like we are flying backwards at a high airspeed, it is more like a slow controlled drift. Once we reduce the collective, the rotor RPM is controlled and recovered (if a droop occured) plus we now have some reserve power to terminate over a point of departure or land. We just flew this path in a climb with little forward speed so doing it in reverse is fairly easy and safe. You must have some references and a plan to return for every departure.

 

This is part of military flight training and where I learned it in the 60s'. I have taught it since then and it is a controlled maneuver.

 

As mentioned, it is a judgemnt call on how you depart (fwd or vert)and maybe different every time. PICs make decisions.

 

Be Safe, Mike

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Once during my Commercial training, my instructor asked that very question just before a max-takeoff from a confined area. I didn't know, so he said, "just go back down".

 

Then we proceeded with the takeoff. Upon reaching the top of the trees, he rolled the throttle down. When the low-rpm horn went off, I simply lowered the collective, and backed my way back to the LZ. I already knew what was behind me (since I had just been there), so no problem. :)

 

You make a low level backwards autorotation sound so easy, I would love to see that maneuver from a safe distance. :huh:

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You make a low level backwards autorotation sound so easy, I would love to see that maneuver from a safe distance.

 

I don't think he meant he chopped the throttle, he reduced it to simulate lack of power. (Top of the green to the bottom of the green maybe).

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Lele, Good post and I agree with your entire post in theory and for safety reasons other than this statement "You are now going backwards, at max power, downwind, into a confined area. You immediately lose whatever translational lift you had and your ROD might very well increase more than you want in this situation."

 

Let me analyze this, yes we are backing down(at a slow rate) but still facing into the wind with a reduced collective and full rotor RPM so ROD is not a factor.

 

The backdown is not like we are flying backwards at a high airspeed, it is more like a slow controlled drift.

 

Here is an example of what i mean:

Let's say there are 5-10 knots of wind, and you are climbing out at an angle, at say 5-10 knots of groundspeed. So you have 10-15kts airspeed on the disc helping you during the climb.

You are still unable to maintain your climb, so now you have to go backwards.

Going backwards carefully at, say, 5-10 knots groundspeed, your fuselage may still be facing the wind but your airspeed is now zero or at least very low.

 

If you were unable to maintain the climb OGE at 10-15kts airspeed, are you able to control your hover back down, OGE at zero airspeed?

You might be, depending on a lot of factors, but it will be close.

 

Like I said, I don't generally say it is always a bad idea, and I have done this myself, but there is a high risk of an overtorque during the abort - or worse.

 

Yterminating back at your point of departure is really simple if you had a return plan prior to initiation.
I think this is a very important point. Whatever method you use, make sure that BEFORE the takeoff, you already know exactly how you will abort if you have to. Edited by lelebebbel

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Discussing departures from confined areas many times brings the same responses about not having sufficient power to sustain a climb or clear an obstacle, maybe with drooping rotor RPM.

 

Training methods often teach a Max Performance take off from the ground. I suggest that for actual operations(non training technique building scenario), a hover check be completed and power required be noted along with reserve power to perform the take off.

If you desire to not hover for any reason(many are acceptable), then as you initiate the lift off make an immediate judgment of power applied and power remaining before proceeding deep into the maneuver. Positonal reference points prior to initiation are mandatory for a safe return but making a decision before requiring an abort takeoff/back down procedure is preferable!

 

Understanding helicopter performance and mentally being ahead of any maneuver/procedure is critical.

 

Situational Awareness(SA) does take place on the ground prior to take off as well as during all phases of flight!

 

Be Safe,

 

Mike

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In my opinion, a confined area, high GW/limited power takeoff is the most difficult thing you can do with a helicopter. It takes the most ammount of discretion with the least ammount of margin for error. Often times it takes every advantage one can get, and TL begins with any forward airspeed, not just until you get into ETL. If you have room to get some airspeed I say use it. I teach, and practice, that as much forward acceleration you can get while keeping your tip-path plane above the obstacle will give you the most lift while giving an easy visual reference that your angle is good. Aborting is not as difficult as its been made out be here by other posters, we're not talking about barrelling towards the trees and getting out with a cyclic climb.

I dont like stationary towering takeoffs because often times you can fall off your column and are decending right at your obstacle until you get ETL. So the argument that its safer to abort at stationary towering t/o is bunk with me. Why not take advantage of translational lift and your power margin in a way that can clearly be measured out the windshield thougout the maneuver.

 

BTW if a student used your yard as a demonstration area for a confined area he'd fail my pre-checkride standards. Its hard to judge from a video but that looks like plenty of room to accelerate past the knee of the HV curve and establish a normal takeoff profile with plenty of room to clear your obstacles. I've never flown a heli-cycle tho.

 

The best advice I can give is to KNOW YOUR AIRCRAFT. Understand and know the OGE hover charts if you have them. Understand what your power checks mean for performance. Experiment on a runway- how high can you climb straight up at MGW? I know my JetRangerIII will only climb to 50' straight up on a standard day at MGW.

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I agree with what I think is Lelebebbel's essential point of discussion- a very important consideration in deciding vertical vs any other departure is that one might not have the power for a vertical and translate at the top. The forward climb is proposed as a method of gaining some ETL advantages... But a position has been taken that you don't sacrifice some of that advantage by reversing the track and backing down? That's not logical, and depending on the specifics, it could present real issues, like being out of ground effect when you reverse the process, at your power limit.

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I don't think he meant he chopped the throttle, he reduced it to simulate lack of power. (Top of the green to the bottom of the green maybe).

Lol, makes more sense. Still a ballsy move though.

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Lol, makes more sense. Still a ballsy move though.

 

What you were saying would be impressive though. I would be standing back with you, watching from a distance!

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I have to agree with lelebeblblblbl. I dont like the idea of running out of power at the top of a cimb and descending downwind with no power left. Remember if you are descending downwind that is where your down wash is. Flying a Cbi Where there is no manifold pressure limits you have no get out of jail free card. you have power then you have over pitching.

 

I have gotten to below the tops off the trees at full power and not been able to go any further. its not a nice feeling only just holding a high hover at full noise. If you then put in a touch of left pedal because of some stupid reason. then the rrpm Will decay. so now you are descending ( no torque turns dont do a torque turn when you are at full power)

Lower the lever to get rrpm back (very important)now you have too much inertia going down to stop the descent so we desend with the maximum power into wind.(usually a fairly slow descent) If you were to do this downwind then good luck to you and goodbye to your machine. If you get to the bottom with too fast a descent to land safely then when your near the ground over pitch it deliberatly onto the ground (note: not from height as you will become a lawn dart)just enough to stop you bending the skids.

 

Lets take it back to the top. if you can not take off vertically (been there plenty of times) then take off rpm top of the green set a 25kt attitude and pull smoothly to full power.. its best to learn what you can and cant do with someone who has some experience. but you will know soon enough if you can make it or not.

 

If you have committed yourself and are just not quite going to make it then let the nose drift right just a little. (non french machines) A little less pedal can give you just enough power sometimes.

Practice over cleared areas with good visual references, like taking off along side some trees to work out your best angle of climb at varying weights and DA's

 

Most important is dont be afraid to do 2 trips to a better more open area. Its sometimes fun to make the other guy walk anyways. :D

 

Just about scared to fly with myself now :blink:

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I have to agree with lelebeblblblbl. I dont like the idea of running out of power at the top of a cimb and descending downwind with no power left. Remember if you are descending downwind that is where your down wash is. Flying a Cbi Where there is no manifold pressure limits you have no get out of jail free card. you have power then you have over pitching...

 

When we got to the top of the trees, my instructor rolled the throttle down to 97%. The horn came on, I lowered the collective (gently) to regain RPM, and simply drifted back down to the LZ, (with some aft cyclic).

;)

 

I didn't think it was that big a deal? There may be no more power to ascend, but it certainly doesn't take more to stop a short descent! My downwash may be back there, but at the top of the trees there's not really enough room to "settle" into it.

:huh:

 

I don't know?...I was in an R44, maybe it would be a lot worse in a CBi? One thing is for sure,...having manifold limits doesn't give us a "get out of jail free card". If the RPM is decaying, your out of power, no matter what the chart says!

:o

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I don't know?...I was in an R44, maybe it would be a lot worse in a CBi? One thing is for sure,...having manifold limits doesn't give us a "get out of jail free card". If the RPM is decaying, your out of power, no matter what the chart says!

 

 

True. what i'm referring to though is that if your using maximum take off power in a derated machine there is something left (should be)even though we are not supposed to use it. :ph34r:

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