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Pinnacle Ops


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Do you guys have any particular techniques you teach / use for pinnacle operations.

 

 

If you look in the General Fourm we recently talked about confinded areas. Pinnacles are prettry much the same in set up.

 

Establish orbit 500' AGL 65 knots (not always going to be 500' above LZ, you should be 500' above all terrian)

 

High recon: AWOTFEEL (estimated Altitude of LZ, Wind, Obstructions, Turbulance, Forced landing areas, Entry, Exit and Landing zone condidtions

 

Based on planned entry: set up traffic pattern, downwind checks done, including power check

 

Final: Low recon, verify items from high recon, continue or go around

 

Landing: if turbulance expected or in high DA do a steep approach, otherwise a normal approach would be best

 

Take off: Checks, recon for departure, normal take off(do not loose altitude when you leave the pinnacle!)

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"Landing: if turbulance expected or in high DA do a steep approach, otherwise a normal approach would be best"

 

A question JD, I understand steep approach for wind/turbulence on pinnacles, but with high DA what does the steep approach do that the normal one doesn't? Is it a power or airspeed issue?

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"Landing: if turbulance expected or in high DA do a steep approach, otherwise a normal approach would be best"

 

A question JD, I understand steep approach for wind/turbulence on pinnacles, but with high DA what does the steep approach do that the normal one doesn't? Is it a power or airspeed issue?

 

It is really kind of both.

 

What is happening in high DA is once you have decided you do have the power to complete the approach and take off you need to keep in mind the helicopter reacts a bit slower and requires more power in higher altitudes. A normal approach will usually result in a lot of power(collective) being brought in late in the approach and the helicopter takes longer to react to that so you may fall through in the end. By doing a steep approach which is done slow, ETL is lost sooner and you'll notice you tend to bring the power (collective) in sooner and also slower. This results in more altitude in which the helicopter as to react to that input. Also, if you discover you actually don't have the power you thought you would have you will have more altitude and time to re-gain ETL and go around. But that should have been caught in the power check. In the end, in high DA it's better to have a slower and more controled approach.

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I've been doing pinnacle landings to offshore platforms for 25 years, and IME steep and slow is the way to go. If you get shallow, you can end up overtorquing trying to get onto the pinnacle, especially if you allow the aircraft to get below the landing area. Then you have to climb in essentially an OGE hover, which may not work at all. If you're steep, you just follow your line to the landing, needing no flare and no huge power increase on the bottom. I try to keep the rate of descent around 200'/min, which seems to take forever, but it's much safer than coming down hot, and hot and shallow can be a deadly combination.

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I've been doing pinnacle landings to offshore platforms for 25 years, and IME steep and slow is the way to go. If you get shallow, you can end up overtorquing trying to get onto the pinnacle, especially if you allow the aircraft to get below the landing area. Then you have to climb in essentially an OGE hover, which may not work at all. If you're steep, you just follow your line to the landing, needing no flare and no huge power increase on the bottom. I try to keep the rate of descent around 200'/min, which seems to take forever, but it's much safer than coming down hot, and hot and shallow can be a deadly combination.

 

 

Good point, I will have students do a steep approach if they are having a hard time and comming in too fast. I was always taught to do a normal approach unless, turbulance, power limited or high DA then work it in slower as a steep app would be.

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JD and Gomer:

 

Thanks for the feedback for a newbie. I have done a few pinnacles at 5300'ft and 4200'ft and we didn't have alot of extra power left over, so it was good practice. We did both types of approaches because of the terrain involved and specific landing sites dictated different techniques. I have realized that to much speed is bad and to little speed can be worse, so a fine middle ground has to be made for the conditions present. On final I have been told that you want to end with zero airspeed and zero R.O.D. at the same time over your spot and terminating into a low hover is the trick.

 

Anything else I would love to hear it.

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It should be noted that steep is a relative term. One pilot's steep is another's normal. My standard sight picture is the pitot tube on the far edge of the landing area, and keeping it there. This isn't a really steep approach, but it is much steeper than some other pilots do it. Just don't get caught flat and slow, with nowhere to go except the landing area. You can easily run out of power and either overtorque or go Splat!. The former isn't good, the latter is very, very bad. Personally, I want to be steep enough that if something happens, either an engine failure or just insufficient power, that I can still make the landing area, even if it's a hard landing. Hitting the legs of a platform, or the side of a cliff, is not gentle. Obviously at sea level there is more power than at several thousand feet, but if you're at max gross wt, 95 degrees, and no wind or an unfavorable downdraft, it's still an iffy proposition at times.

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Thanks for all the feedback. I'd never done real pinnacles before, just simulated to a surface pad. It was interesting. When you guys depart do you ussually lift off and back away then accelerate forward, or do you just lift off and accelerate forward? My instructor says both ways are ok, just getting the feeling of the group on what most people think is best.

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The departure depends on the model and the power available. Ideally, a performance class 2 departure is good, but not always possible. In the real world, we take what we can get. For PC2, climb vertically to 10' skid height, then accelerate forward. I've made thousands of takeoffs in which this wasn't possible, in which case we get to the edge of the helideck, with the blades over the edge, hold an absolutely steady hover without moving either the cyclic or collective more than necessary, and wait for lift. It will eventually come, and then you go over the side, making sure to not hit the tail rotor. We've been doing this offshore for more than 50 years, and I've never heard of a tail rotor strike on takeoff. They happen on landing, after a hot shallow approach with a flare at the bottom.

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I've made thousands of takeoffs in which this wasn't possible, in which case we get to the edge of the helideck, with the blades over the edge, hold an absolutely steady hover without moving either the cyclic or collective more than necessary, and wait for lift. It will eventually come, and then you go over the side, making sure to not hit the tail rotor.

Holy cow! I never thought that oil platform take-offs were so exciting. :o

I thought that close to sea level, there would be plenty of power for an easy take-off.

Are you just so loaded down that the power is marginal?

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I've never heard of a tail rotor strike on takeoff. They happen on landing, after a hot shallow approach with a flare at the bottom.

 

I am asking this mainly because of ignorance, but why do they have so much forward airspeed when they come in for a "hot" and shallow approach? Is it because they are at max weight and can't afford so come in with less airspeed so they flair over the landing area to come to a complete stop?

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Whirlwind, almost every takeoff is at (or above, depending on how much lying has been done) or above max certificated gross weight. The max gross weight has been increased over the years until it's at the point where the aircraft will just barely hover in the summer.

 

Brushfire, about all I can say is poor technique. As for the why of the poor technique, I can't say. In some cases inadequate experience, maybe in all cases. Some pilots have flown for ten thousand hours, and some have flown for one hour ten thousand times.

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From the single-engine military perspective, I'll have to echo Gomer; steep and slow. Usually, this keeps me above the line of demarcation, and requires the least amount of power changes. I'll be at a power setting in between IGE & OGE hover power which keeps that slow rate of descent that keeps me from settling into the VRS. All of this is very important when there is nothing below you except steep rock slopes. Or even if it isn't steep and just rocky.

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A handy way to ensure you follow your approach line to a pinnacle and not sink below it, is to use the "gunsight" approach.

 

When you are established on the correct line, look beyond the pinnacle to an object just above it in the far background. Keep the two aligned, like a gunsight. If the distant object disappears, you are too low, and should have time to correct the approach. :rolleyes:

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