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Mountain Approach Procedures


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#1 Inthegreen

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Posted 09 May 2006 - 00:37

Just throwing a topic out to the group for discussion. Every pilot flies a little bit differently, with respect to their training, their experience, the diversity of their missions and the amount of exposure they've had to more experienced pilots.

I'm interested in what procedures other pilots use when conducting mountain approaches. I have my own procedures, which are not unusual or unique in any way, but there are many ways to accomplish the same feat. If you feel like responding, give your procedure/s as well as your reasons for doing it that way.

Thanks

(Also posted at PPrune)

#2 crashresidue

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Posted 09 May 2006 - 03:52

First off - what altitude are we talking about, and secondly, what type of mountain?

Is it above or below 8,000 ft and is it a rounded or knife edge landing site?

Either way - ALWAYS lead with power!

cr

#3 Inthegreen

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Posted 09 May 2006 - 13:05

First off - what altitude are we talking about, and secondly, what type of mountain?

Is it above or below 8,000 ft and is it a rounded or knife edge landing site?

Either way - ALWAYS lead with power!

cr


Well, if you have the time CR, maybe you could discuss the difference between those conditions.

#4 crashresidue

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Posted 10 May 2006 - 00:07

Cheers,

After re-reading both of our posts - I MAY have opened a huge can of worms. But, I like to fish, so what the h*ll.

First off, I read it as a "mountain approach" not a "mountain top approach" - there a whole world of difference.

"IN MY EXERIENCE" - please note this is just my opinion/experence - it's NOT to be taken as "written in stone". OK?

Knife edged ridges above 8,000' have close in, more "violent" turblance (burble). You get slammed on short short final, not 100 yards out. Your airspeed is slower, your reaction time is VERY short, and it's going to take everything both you and your a/c have to survive.

Rounded mountains produce turblance that you find farther from you landing site. Your airspeed is higher, your reaction time is longer and you're NOT yet committed to final approach because you have more altitude under your skirt.

The "Helicopter Handbook" recommends that you use a steeper apporach for higher winds(turblance) when landing on mountains. The LAST thing I'll ever do is shoot a steep approach at altitude. I've seen too many wrecks and come too close to scattering my own doing it the "recommended" way.

Now, this is a "risk accesment" call - it all depends on what makes you the most uncomfortable.

Terrain permitting, I shoot a quarting wind shallow approach to the ridge line and hover to the landing site, sliding up or down the ridge. I know all about the "deadman curve" - but since I've done 133 since 1980, I'm comfortable working in that environment. If I smoke a motor, I'm in no worse shape that having it happen on short final.

I will also shoot as many approaches as it takes to make me comfortable. I did a repell a few years ago where I shot 18 approaches before I found an ingress route that made me comfortable. My foreman, in back, said that this was the only approach that made him comfortable too. No harm, no foul!

"Lead with power" - that means that you've got 90% of hover power pulled in BEFORE you come out of translational lift. The last thing you want to do is droop your N2 at the last second. Droop the main-rotor and you slaughter your tail-rotor control - at altitude, that's dead!

OK, now tell me how you do it? Your way may be better than mine - and since I'm still alive, I must be still learning!

Gentle winds,
cr

Just noticed - you joined here after I did - yet your memeber number is lower than mine!!!

Now I'm REALLY p*ssed :lol: .

cr

#5 Firepilot

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Posted 10 May 2006 - 01:07

I'd have to agree with the above. Flatter approach, power in early. The "steep approach/demarcation line" type approach from the Basic Helicopter Handbook doesn't work in the mountains. Always leave youself an out.

#6 Gomer Pylot

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Posted 10 May 2006 - 09:48

I admit I don't do much mountain flying, but I do regularly land to elevated helipads, a couple of hundred feet high, at or near max gross weight, at 90+ degrees F, with relatively high DAs. Having done this several times per day, every day I work, I've found that a steep approach is by far the safest. If I do have a problem, either engine failure or just insufficient power, the steep approach lets me at least hit the pad I'm aiming at, and not the side of the platform. I fly an approach that puts the pitot tube on the far edge of the intended landing site, and have the power in somewhat, keeping a 200-300 fpm descent rate, and whatever airspeed I get to keep the angle and descent rate. This is pretty much the standard Cat A profile published in the RFM, but probably a little slower. It's always advisable to read the flight manual, understand the charts, and fly the profile the test pilots found to work best. Being your own test pilot can be hazardous to your health.
Best Regards,

Gomer

#7 Inthegreen

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Posted 10 May 2006 - 15:52

Thanks Crash (and the others) for your reply. I'll give you my version. It'll be kinda long. When I typed the original question , I was picturing in my mind mountain approaches in general, not necessarily to the mountain top, but possibly to an inferior ridge, knife-edge perhaps, but not necessarily, or to a confined spot in a drainage. I was fishing for speeds, descent angles, descent rates, closure rates, windward/Lee, approach track angle to the ridge, etc. I didn't specify because I wanted everyone to identify what was most important to them. Your response was exactly what I was looking for.

My procedures are essentially the same. I'll post everything I do, even though some are incredibly obvious.


1. Recon - The intent is to identify the safest way in and out. I'm looking for wind direction (though it may be different at the LZ than from where I observed it), obstacles, slope, surface, FOD, best fly-away, best approach track and angle and etc. My last full circle in the recon will end with a slow parallel course to the approach, offset to the safe side, to gauge what the wind will do and if there is an updraft/downdraft to deal with. I assume that every mountain approach will terminate to an OGE spot, if I happen to get IGE performance, that's just a bonus. I check my OGE table for my maximum weight under current conditions (I generally prepare a table of weights for each 500' altitude and 5 degrees temp up to the highest expected landing I'll encounter, so I won't have to try plot something on the rfm OGE chart while flying).

2. Setting up the approach - In ideal cases I prefer a shallow approach angle with a track that is at an angle to the ridge if there is one. If it is practical, I may fly down the ridge sideways with my nose yawed into the wind. Cases where I would choose a steeper than shallow approach (but technically still not steep), is obviously for obstacles, terrain restrictions or adverse wind on the shallow approach that is not present on the steeper angle., or etc. I try to stay away from steep approaches due to the larger collective movements required and tendency toward higher descent rates. If no other approach is possible, a steep approach can be accomplished by flying it slow and controlled with power in early and very low descent rates (this applies though to any regime of flight other than maybe OEI.)

Preferably, I would set up the pattern to allow the best fly-away to be on my side, so I have maximum view of it. In right-seat commands, this would be hugging the left canyon wall and making right turns. Obviously, wind and other considerations may make this unrealistic.

3. The Approach - slow and controlled with power in early. The approach can begin at any airspeed really. It's not imperative that it start at 60 kts or any other number, just that it stays comfortably above ETL until the very end. In fact, carrying too much airspeed can mask the real performance that you will encounter when you get in close. I want to know early if performance is going to be a problem so I can peel away. In many aircraft, especially ones with larger instrument panels that restrict forward vision, I'll yaw the aircraft and look at the LZ through the triangle between the panel and the corner of the window or partially with the side window. One drawback is that your indicated airspeed no longer agrees with actual airspeed. You have to gauge airspeed by feel.

This is the standard approach. In some cases, the best approach may be entirely on the windward side, side-stepping into the LZ at the end. In other cases, the best approach may be flying in the flow of the major ridge, then slipping down the finger ridge to the LZ. There are obviously millions of possible variations.

At any point on the approach I should be able to fly away until the very, very end as I'm touching down. I would avoid any approach that would make me commit too early unless the aircraft and the wind were both very light.

All along the final approach my senses are heightened for changes in aircraft attitude or position, indicating up and down drafts, cross-winds or etc. If I experience any unusual tail rotor requirements, I suspect that I have a strong crosswind component and may need to rethink my approach course, because that t/r requirement will become a power requirement the closer I get. If the approach is requiring me to make large collective changes to keep up with up or down drafts or thermals, I also may wish to find another way in. There's nothing worse than getting close and having to bottom the collective to maintain your angle. I am also looking for anything else I may have missed in the LZ (wires, stakes, etc.) from my higher look. The final 100 or so horizontal feet of the approach is essentially a hover. Carrying too much airspeed into the spot can be disastrous. I don't like the technique of flaring at the spot.

4. The landing - preferably into the wind to minimize tail requirements. If there is a slope, it is preferable to land with low skid down hill. (In american a/c, that would be left skid) Obviously, consideration must be made for tail and rotor clearance. If a crewmember is aboard, it is useful for them to give a visual of the tail and skid positions before power reduction is commited to. After initial touchdown, power should be lowered gradually to ensure stability on the surface.

5. The departure - preferably into the wind. After clearing obstacles I would attempt to achieve at least best rate of climb speed as soon as possible (60 kts in most a/c). Fly toward the best fly-away.

This is how I do it. I'm not a mountain guru or anything, but these procedures have kept me comfortable.

ITG

#8 crashresidue

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Posted 11 May 2006 - 00:59

ITG,

We're on the same page. Now, we just have to stay alive long enough to pass it on!

Some where, I've got a picture of my Lama, sitting on a remote pad at about 12,000' and right next to me is an AirFast Bell 204 laying inverted in a shallow ravine next to the pad.

He shot a fast, steep approach and found out, at the bottom, he wasn't as smart as he thought he was.

The geologist I was supporting was picking on me because the "last pilot we had did the approach faster" and when I didn't get angry, he pointed to the wreck and said that it was the "last pilot's" last flight for them. No fatalities, thank God.

Gentle winds,
cr

#9 Kuma

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Posted 12 May 2006 - 23:23

Wait a second... I was always taught that landing low skid uphill was the best. That way, you can evaulate if you have sufficient control authority to land. Reposition if you need to. On the take off, everything (meaning torque and and t/r rotor effect) is helping you uphill.

Like cr mentioned in another post, I'm still alive, so I am still learning. Please tell me what I am missing from this equation.

Kuma

#10 flingwing206

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Posted 13 May 2006 - 08:01

The tail rotor is trying to roll the helicopter away from the low skid - better to have the T/R trying to roll you uphill, hence low skid downhill. You're going to learn about control limits anyway.

#11 Kuma

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Posted 13 May 2006 - 09:52

The tail rotor is trying to roll the helicopter away from the low skid - better to have the T/R trying to roll you uphill, hence low skid downhill. You're going to learn about control limits anyway.


Man, I was so wrong. Everything you all said made sense, but I still thought that the lower skid should be up hill. I went back and did some research and found the following comment in the AH-1W Manuever Description Guide



Note
Slope landings may be performed with either skid down
slope, but right skid down reduces the critical dynamic
rollover angle; i.e., it is better to land left skid down (AH-
1W NATOPS Flight Manual, Chapter 11[Paragraph 11.7]).



The cobra has a counterclockwise rotor and the left skid is the lower skid.

I've been doing it "wrong" all this time. Chalk up another success story for VerticalReference!!!!

Thanks guys-
Kuma

#12 Paddy

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Posted 11 June 2006 - 03:49

Hi,all of you mountain goats..
We fly every day in the alps up to 4600 m doing sling and rescue ops. Once a year we fly in the himalayas for heliskiing higher up to 6000 m.
What I've read is what we use but if you want some more try to contact our Federal office for civil aviation as we have a special module dedicated to mountain training. We also have an attachment to our licence.
www.bazl.admin.ch and try to go under documents then helicopter and you will find all the files related.
Happy landings

#13 Krusty

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Posted 14 October 2006 - 15:08

Great Topic!!!!!

Always check Altitude/Ingound effect / Hover perfomance information outlined in the AC manual!!

Mountain and narrow saddle: I use a reduced airspeed once it can be esablished after a countour crawl to acertain the correct shallow approach altitude, angle and wind/ powercheck. Approach when possible from 45 degrees , I like to treat every spot like a narrow saddle. The 45 degrees gives me a shorter turn if things go bad on final to get my airspeed back down hill.

As for hill side landing and tow-ins, the standard figure 8 pattern works great. 3500hrs in mountains and counting.

Note: Before flying utility in the mountains I would highly recommend some mountain training from and experience mountain pilot. Please do not try any of the above written statement at home without first consulting..............

Fly safe

Krusty




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