Mountain flying forum at osh

[Bill Greenwood]

I am already thinking about going to Oshkosh, and looking forward to it, despite having about 3 in of new snow on the ground.

I am doing a presentation on Mt. Flying this year, and I wonder is anyone has any specific questions or areas that I could prepare for or cover.
If so, please give me a brief idea here.

And this is oriented toward someone who might be flying into Colo. for vacation.
It should be mostly applicable to other areas as well.

It's not Alaska type bush flying.

I did this the 1st year at Sun N Fun, and just before the start, I thought, "who cares about this in the middle of Florida", but was surprised at a decent turnout and good reception.

There have been other presentations of this type, but mostly they are not from those living and flying in the middle of the mountains.
Thanks

[gbrasch]

Bill, I think this is a great idea on your part. When I learned to fly as a kid in Illinois, density altitude was only something I read about in a book. Now after thousands of hours in the mountains it is something I view with great respect. Good luck!

[Bill Greenwood]

Glenn, I don't fly copters but was just talking to a friend who has a new one here and the service ceiling at about 13,000 due to something like retreating tip stall if I have the right term.
He was doing a search for a local missing skier, and being very careful in a valley surrounded by peaks at 14,400.

Medevac service is invaluable here, especially in winter. It is 90 air miles to the nearest big trauma hospital. Folks love to get outside, but you can get in trouble.

[danielfindling]

I live in S.E. Michigan where the terrain varies by maybe 500 feet over the course of the State. Notwithstanding, I love the romance of Mountain Flying and I dream of flying my Cessna 140A in the "bush".

Here are some questions I would like explained:

The concept of a rotor on a the downwind side of a mountain with low and slow flying. Is there a minimum altitude above a peak necessary to avoid the rotor?

I remember reading that Steve Fosset died in a SuperCub in part because the downdrafts exceeded the airplanes ability to climb. What factors (in addition to density altitude) should a pilot be aware of? Is there a critical wind speed/Altitude over a Mountain to avoid?

Emergency procedures with Mountain flying: Where do you put a plane down?

Hope this helps. (Oh, and I would love to hear your opinions on the questions posed.)

Daniel


P.S. I asked a bush helicopter pilot during a ski trip how he accounted for rotors and he gave a reply akin to watch for minor airspeed fluctuations, and seat of the pants (feel of the airplane) response that did not make a whole lot of sense to me.

[Joe Delene]

Thanks, those educational & safety forums are one of my newer favorite things to do at Airventure. I went to several last year & may do even more this year.

[Victor Bravo]

Bill, maybe spend some time on explaining how wind moving through a pass or a gap creates sinking air downstream of the gap. Approaching a high pass from the downwind side will put you in a combination of headwinds and sink that can easily overcome an average airplane's climbing and penetrating ability.

Random ideas:

Staying the hell out of wave systems until you have had some wave training in sailplanes.
Staying well beow maneuvering speed/gust speed when flying through wave rotors.
Using the lift on the windward side of a ridge,a nd not flying along the downwind side.
Always leaving an "out" where you can "fall away" from any hill, or the mountain range, to lower terrain.
Never turning downwind when that turn is toward the mountain.
Using the artificial horizon as a frequent reference, even in VFR conditions, to augment the compromised visual "horizon".
Use of partial wing flap deployment to increase control authority and stall resistance when maneuvering at low speed and high DA.

[gbrasch]

Glenn, I don't fly copters but was just talking to a friend who has a new one here and the service ceiling at about 13,000 due to something like retreating tip stall if I have the right term.
He was doing a search for a local missing skier, and being very careful in a valley surrounded by peaks at 14,400.

Medevac service is invaluable here, especially in winter. It is 90 air miles to the nearest big trauma hospital. Folks love to get outside, but you can get in trouble.

You got it Bill........the "official" term is retreating blade stall, close enough. Here are the factors that contribute to it, as you can see, density altitude is on the list:

High gross weight (http://en.wikipedia.org/wiki/Gross_weight)
High airspeed
Low rotor RPM (http://en.wikipedia.org/wiki/Revolutions_per_minute)
High density altitude (http://en.wikipedia.org/wiki/Density_altitude)
Steep or abrupt turns
Turbulent (http://en.wikipedia.org/wiki/Turbulence) ambient air

[Bill Greenwood]

Dan, as for how far to fly over and clear a ridge by in order to avoid turbulence and downdrafts on the leeward or downwind side; just as a rule of thumb, about 2000 feet above the peak is usually ok. BUT IT DEPENDS. The three main passes that I cross going to Boulder/Denver are about 12,000, so I may go east at 13,500 or a little higher and west at 14,500. It depends on the winds aloft, which we get from FSS at 9, 12, and 18. If they are for instance, 15 knots, 20 knots and 45 knots, then 2000 feet AGL or so is probably ok. If they are much higher, say 25 knots, 35 knots, 55 knots, I would likely go to 4000 feet above to cross the pass. 40 knots at 12 is pretty much the limit of what I will fly in, but I would also check for pireps along the route. If only light turb is reported or even moderate by a pilot who is flying low, the I could probably cross ok at 15,500 or 16,000 and not descend till I was past the turbulent area,
But, I would be very careful and often cancel if someone where I am going has reported mod to severe especially if it is a large plane. Having been in severe once or twice where it put my head into the roof and tossed off my headset and all the ash trays out of the holders and papers on the floor, I don't want to do it again. Fortunaltely I had slowed down,but it still feel like getting hit by a linebacker that you didn't see coming.

My turbo Be 36 will easily go above 16,000. If you are in a 140 then you need to go on a calm day, usually early morning. You can cross at 12,500 but there is little margin for error.

I aim so when I cross I am as high as I need to be, and going into lower terrain, and always with room to turn around.

[AmigoOne]

Hi Bill, I live in Virginia next to the Appalachian and I have a good idea of the amount of turbulence that these mountains can generate on windy days which I'm sure they are child's play compared to the Rockies. This summer after Oshkosh we are planning with a friend to cross the Rockies in our way to Seattle. Throughout the years I have purchased a mountain flying video, read articles and most recently at S&F I got the shirt pocket guide by Sparky Anderson. Still as a flatlander I will start the summertime journey over the Rockies with a healthy degree of apprehension. Leaving Oshkosh we plan our first stop in Rapid CIty, SD and from there I would like to ask you, if you know, what would be the best route to make at least the navigating route a bit easier. The weather is another issue and I'll continue to study the subject. We will come back over the southern route where the desert heat becomes an issue and for that I guess that the best strategy is a departure before sundown and landing at or before mid-day. I would have preferred a different route and to do it might depend on the experience of the first crossing.
I'm also planning to attend your seminar at Oshkosh. We will be flying a 1968 Mooney Ranger.

[Bill Greenwood]

Amigo, my first airplane was a 1970 Mooney M20 C Ranger.
Let me take a look at the route up north to Seattle and get back to writing in the next day or two. I have flown from Osh to Seattle, but it has been years ago, and I was in a much different airplane. I have also flown a few times from Colo to Wash in some other planes,one a T-34.

Just in brief, go in good weather, probably early morning flights. Have O2 on board, keep the load light.

[Mtns2Skies]

I'd recommend you advise they go up with a local CFI before even approaching the mountains. IIRC (could be completely wrong) But I've heard more Texan pilots die in Colorado than Coloradan pilots. I understand that you are a very competent mountain pilot, but I'd definitely stress the danger present, and the respect that pilots MUST have to fly in the rockies. (With naturally aspirated piston aircraft)

[AmigoOne]

As I said before I am respectful of these mountains and I'm planning to acquire as much knowledge as possible before leaving. And no, I am not a very competent mountain flying and that begs the question whether or not I should attempt this flight. My review of a route I have tentatively planned tells me that it can be done between 10-12K feet, well within that capability of my airplane. The issue for me always has been the weather and how to interpret how it affects mountain flying. One thing for sure, we will only fly in clear weather. Not mountain IFR for us.

[WLIU]

One of my pet topics is how when flying in mountains under a ceiling that is good VFR but precludes flying over to peaks, you need to have good sectional map reading skills. The newer GPS units show terrain, but if you turn down the wrong valley you can get into serious trouble. Without local knowledge it is unwise to go further into a valley if it is getting too narrow to do a comfortable 180 turn. And don't go through a pass or notch if you do not know that you can come back.

I have a relatively fun but challenging task that I advise pilots to try on a clear and blue day in tall hills or mountains. Try and do a 50 mile hop through the rocks at 500' to 1000' AGL, where you can't see over the ridges. Look at your sectional before you get in the airplane and figure out a route through the valleys. Then go try to fly it. If you really really get lost, climb above the tops of the hills to look around and see where you got to. Then go back down and try to get back to where you want to be. It is an interesting game on a nice day with low winds aloft.

Don't know if that sort of learning exercise fits into a mountain flying lecture, but I learned about flying in the rocks the hard way like most folks I know. I grew up, aeronautically speaking, around them.

For flatlanders, I would suggest that flying in the mountains is not very hard, but they require simply thinking about what they are. I assume that any lecture covers topics like
A) At night there are no obstruction lights on the rocks,
B) The tall rocks bend the wind currents as well as cause turbulence so the wind direction at two airports 10 miles apart can be reported as being completely different.
C) Tall rocks block you comm radio as well as a VOR. So if you are in a valley and the destination airport is around the other side of a tall rock, unicom likely will not hear you.
D) The wind accelerates as it flows over a ridge just like it accelerates when flowing over your wing. It is not particularly uncommon for your ground speed to go way down, even to zero on a windy day, as you approach a ridge from the downwind side. And you might not be getting turbulence depending on the contour of the ridge, the wind speed, and the stability of the air mass. So if it feels like you will never get over the ridge in front of you, you may be right, or you may just need more fuel and patience than you planned.
E) Flying VFR in the dark around tall rocks without lots of local knowledge is not for the faint of heart. A clear sky and a full moon helps, so you can get quickly up above the ridges, but it is not uncommon to hear of a pilot taking off from a well lit airport, turning, and flying into a dark ridge a mile away. If you feel the need to launch or land at night amongst unfamiliar rocks, stay right above (and I mean RIGHT ABOVE) the airport when you are below the ridge tops.

The guys in Colorado, Wyoming, Montana, Utah, etc will add comments about leaning on take-off and density altitude.

The sum total is that you have to think about where you are headed and the time of day.

Just a few thoughts.

Wes
N78PS

[Bill Greenwood]

Amigo, of course you can fly over the mountains to Seattle, with the right planning and weather caution, and do it in the M 20C.

The first point I cover in my discussion is what type of plane is enough, and by that, mostly I mean one that can climb to 15 or 16,000. There are 52 mt peaks in Colo over 14,000 feet, and if the plane you own or rent can't get there, then you are forced to fly lower, which is possible and even advisable, in some places. There are many passes between 10,000 feet and 12,000 feet high so you MAY get over at 12,000.Aspen is at 7800 feet and there is both a northern and southern way to come in from Denver, but both passes are 12,100 ft,and that is the highway. But I prefer not to be limited to only flying below the peaks. You can fly in a C 152, which has a service ceiling of about 12,000 or a C172 which goes to about 14,000, by carrying one one or two people and going in the cooler mornings. But it's like trying to play in the NBA, it"s a lot easier if you are 6' 10" rather than 5'10". It is eye opening to fly a landing and takeoff in a 172 at Leadville in the summer with the airport elevation at 9927 feet. You can lift off the runway, but it struggles to climb while the trees at the end just seem to get taller and taller.
So it is a lot better to have a little more airplane, say at least a 182 and a Mooney Ranger fits that bill just fine. I can't recall exactly, but I think the service ceiling is at least 16,500 and I flew mine not only in Colo mountains but also California and down to Florida to go to Flightsafety.

Wes has some how to points about to fly in the valleys and the most important one is to make sure to have room to turn around if you must. But I prefer not to be limited just to the valley, and especially if I was coming from somewhere else and not familiar with tht terrain, and certain of what is at the other end to that valley.

[Hal Bryan]

Amigo, of course you can fly over the mountains to Seattle, with the right planning and weather caution, and do it in the M 20C.

As an aside, I used to fly back and forth across the Cascades fairly regularly in a Cherokee, 172, and most often a Cardinal RG. If it was CAVU or nearly so*, following I-90 through Snoqualmie Pass is a short and easy route, with a few airports and a number of other passable emergency landing spots on the way. I've flown it as low as 5,500, but was happier (and the view was better) at 8,500 or 9,500, depending on the direction.

Anyway, I'm the furthest thing in the world from an expert on mountain flying, but I always enjoyed this route. I never needed it, but there was always the backup plan of heading south and going through the Columbia gorge if I was worried about getting stuck on one side or the other.

*-And if it wasn't, I just didn't go.

[WLIU]

I will suggest that Cessna's have service ceilings in the low teens of DENSITY ALTITUDE, which on most summer days means they top out around 10,000' to 11,000' MSL. I recall one day just west of SLC when I was looking at just clearing the peaks of the Wasatch, or maybe having to dodge through a canyon, to get into Wyoming. I was talking to SLC center, and I think that the bottom of the controller's sector was at 10,000. I was at 10,300 and when he told me to "maintain at or above 10,000 feet", my reply was "Sir, I'm trying!".

I will suggest that if you are talking about mountain flying for guys who can easily cruise at 15,000 or higher, your audience size goes way down. I have peers who will suggest that at those altitudes you are no longer talking about mountain flying, just shooting approaches to places where you do not want to look out the windows at what is around you once you cross the final approach fix.

There is a large target audience of folks who fly normally aspirated airplanes, not equipped with oxy, that can get great benefit from an experienced voice. I know as I used to be based at an airport at the south end of the Green Mountains of Vermont and for some reason after a number of pilots had frightened themselves silly, or tried to land up north and broke part of their airplane off trying to land but didn't quite crash, they came to our place to stop or crash where there were services and staff that would take care of their situation.

That said, the pressurized airplane and kerosene burning people go to OSH also, so the presentation attendees will likely walk away a little smarter.

I will note that Hal's explanation of having a plan and a back up plan is a great example of how to approach a flight across a patch of tall rocks.

Best of luck,

Wes
N78PS

[AmigoOne]

Thanks to all for the useful information and the encouragement. So far from Rapid City after visiting Mt Rushmore, I am planning Billings BIL, Bozeman, BZN, Helena HLN, Missoula MSO, Spokane (airport not decided), Bowers ELN, and Seattle PLU. Tried to pick a route following highways or rivers which may change because if we have great weather we will try to cut across between airports when possible. Comments and Pireps on these airports and/or suggestions on others en route will be appreciated.

[WLIU]

Going that route I suggest that trying to follow I-90 is wise. If you run into problems and have no where else to go, you can land on or next to the highway. That means that help will come by. If you fly a route out away from heavily traveled roads and you have a problem, you might have to hike a ways from where you park the airplane.

Watch your fuel. You can get out to where if the weather or terrain is not kind to you, you might not have enough fuel on board to retreat to the airport that you launched from.

The good news is that the nice folks who build airports out there made the runways plenty long. 6000' x 100 is not uncommon for the municipal airports. The air is thinner and the airport builders accounted for that.

Most of the airports on that route are at 4000' MSL but you might run into one or two at 6000'MSL. Remember to lean before takeoff.

That kind of trip should be great fun. The scenery is great.

Best of luck,

Wes
N78PS

[Bill Greenwood]

Hal's idea of following a major intererstate highway through a big valley at as low as 5500 feet may be fine for Washington or other places, but there are a few problems doing that in Colorado. First, while there is a big highway 70 that goes west from Denver up in the mountains past Vail, on near Aspen and even out the west side of Colorado, but if you are going to follow it in an airplane it would be best to have the plane on a trailer with the wings folded, since the road goes through several tunnels,and up to 12,000 feet.

If you intend to fly over the tunnels, then you are once again surrounded by mountains peaks mostly above 14,000 feet, and few flat places to land in the middle of them unless perhaps you are flying a Super Cub and are very good/lucky.
As for as the 5500 foot cruise, well Denver is the Mile High City, so that means 5280 feet at takeoff so it will be hard to clear many buildings at 220 feet AGL.

The big north/'south ridge of mountains that lie just west of the major towns/cities of the front range are called the Collegiate Range, and there are a bunch of them over 14,000 feet. One is Mt. Harvard, but it really should not take an Ivy League degree to think that being able to fly to 15,000 , IF AND WHEN NEEDED, is a good thing.
When needed may include problems of turbulence if the winds aloft are over 35 knots and/or visibility problems some days or as Flight Service says, "VFR flight not advised in areas of mt. obscurment." But they can be such spoil sports and what do they know anyway?

[Hal Bryan]

Hal's idea of following a major intererstate highway through a big valley at as low as 5500 feet may be fine for Washington or other places...

For clarity's sake, in the specific route I was talking about - Snoqualmie Pass - the max roadway elevation is just over 3000 feet, and the Cascade range is very narrow at that point (which is why they put a pass there) so your time actually "in the mountains" is maybe 15 minutes at a "normal" GA cruise.

[WLIU]

So as this thread drifts along...

If you are traveling across the west and you do not need particularly to go to someplace in Colorado I suggest following I-80 through southern Wyoming to Utah, or the reverse. Navigation is easy, I-80 actually is about 6000' MSL most of the way but you wind between the clumps of peaks and there are airports at good intervals. Weather is almost the same as Colorado, which means mostly clear with the odd crappy day. You don't have to fight the Rockies as the road builders found the easy way. In fact, I-80 follows the same route across Wyoming as the original transcontinental railway. Which followed the wagon train route.

I flew an antique airplane from Boston to San Francisco and back and essentially followed I-80 from coast to coast. Made crossing the Continental Divide relatively easy. For a more northern route, I-90 works. I Follow Roads....

To Bill's point, you have to look hard at a sectional chart to understand how the mountain passes are configured. For example, Donner Pass from northern CA to Reno NV is 7000' high. On a cloudy day you might not be able to make it. Or another example is Hot Springs AR. If the ceiling is 2500' you can do pattern work around the airport all day but you aren't getting out of the valley to go anywhere else. In areas like these you have to know how get get more info from your chart than where the airports and VOR's are.

And Hal, I will guess that if the ceiling at Snoqualmie pass is 800' agl, but you know that the weather is stable and also good on the other side, that can still be a very long 15 minutes.... But the short and narrow ranges are a great way to learn about flying around rocks. You can go see but back out quick before Mother Nature closes the door behind you.

Fly safe,

Wes
N78041

[Hal Bryan]

And Hal, I will guess that if the ceiling at Snoqualmie pass is 800' agl, but you know that the weather is stable and also good on the other side, that can still be a very long 15 minutes....

Fly safe,

Wes
N78041

I'm sure you're right, but I wouldn't know - I never needed to cross so badly that I'd have considered going near it in those conditions.

[Bill Berson]

One of my pet topics is how when flying in mountains under a ceiling that is good VFR but precludes flying over to peaks, you need to have good sectional map reading skills. The newer GPS units show terrain, but if you turn down the wrong valley you can get into serious trouble. Without local knowledge it is unwise to go further into a valley if it is getting too narrow to do a comfortable 180 turn. And don't go through a pass or notch if you do not know that you can come back.

Wes
N78PS
Well said.
Lots of airplane wreckage is seen on mountainsides in Alaska where the pilot got lost and tried to go up a dead end pass thinking it was the real pass.
Not many roads to follow in Alaska.

[Bill Greenwood]

Two C-47 pilots told a story one year at Ohkosh about similar flying in Alaska, that brings chills to me even thinking about it.

They were flying a C-47 for an oil company way out in the boonies and the route was to climb to about 12.000 and go over some mountains until they came to the area near their desination. They had sort of a homemade IFR approach, since there were often clouds obscuring the way. They would find the mouth of the pass that led down the canyon and about 10 miles or so down there was the small airstrip and the work camp that depended on them for vital supplies. There was a beacon at the camp that they could pick up , but only once they descended into the canyon and flew around the final bend.
All went fine for months, but one day the weather was even more low clouds, but they were being well paid to do a job and men depended on them.
So they let down into the clouds at the mouth of the canyon and kept going and kept descending,flying the correct heading and finally broke into the clear at only a few thousand feet.
As they followed the canyon around the last bend, their hearts almost stopped. They realized that instead of the camp and airstrip they expected they had somehow gotten into the wrong valley and it ended in a mountain range. There was not room to turn around, nothing to do but pitch the nose up to best angle of climb, go to full power, full rpm, gear up and try to outclimb the terrain.
As they go back into the clouds, without being able to see what is in front of them, there is nothing to do but hope the plane doesn't fail them and both pray as hard as they ever have in their lives. They have several minutes to sit there, totally blind in IMC, and finally they pop out the top into clear air and are able to turn around and live another day.

I heard a recording of some unintentional flying in a mt valley.

Two guys were on an IFR flight plan, up high, perhaps 15,000 in an MU-2 when they got in bad icing conditions. They lost an engine and began to drift lower toward the terrain. They were on radar and talking to a controller, who gave them a vector and said they were ok down to about 8000 feet. Then the other engine quit, and a MU doesn't glide well, has wings the size of a Cub and weighs a lot more,especially with ice.

The radar controller is great, he stays cool and gives them a the best heading he can so that they go over the lowest valley. Then he loses even radio contact with the pilots.
The pilots have had plenty of time to secure the engines, feather the props and try to restart, but nothing works, They pray hard and keep sinking in solid IMC conditions.
Finally, about 3 minutes later the controller gets a radio call from the two guys he really never expected to hear from again.
"We"ve got one running and we are climbing", but they are not out of harms way yet. Finally, "We've got them both running and are climbing through 7500 feet."
After the they get clear on top and everything settles down the controller asks, "How low did you go?" and the answer "4800 feet". He is stunned, looks at his chart of all the terrain around that area with only one little sliver clear that low, and tells them, "If you went down to 4800 and you are still talking to me, it's a miracle."

They thanked the man greatly for his help.

[AmigoOne]

All these are great stories, keep them coming. I'm getting both more excited and more confident that just concentrating in the two or three major recommendations the trip can be made safely. Of course I continue to harbor a reasonable amount of apprehension which I believe it is good.

[N222AB]

Bill, I will also be giving a mountain flying talk on Tuesday at 11AM in the FAA building. I gave one last year and was surprised at the big crowd and interest in the topic. I gave seminars a couple of other times back in the '90s with the same interest, so I'm sure whatever you decide to discuss will be well attended. My talk this year will be on reading the clouds and understanding how the winds interact with the terrain (with some time lapse videos), along with a few other topics. Let us know when you'll be talking so we can all attend!

Bill

Bill Standerfer
Chairman - Colorado Pilots Association Mountain Flying Program
FAAST Rep

[Bill Greenwood]

Thanks, Bill. I think I may have asked EAA for pretty much the same time slot. I can't recall for sure, but I will check and see and try to make sure we are not at the same time. My talk is not that formal, just trying to get people to be safer, yet still enjoy flying to and in the mountains.

Today was such perfect weather, CAVU and light winds. We flew over Corona around 1 pm.and not even a bump.

Are you based at Ft. Collins, that is Loveland, and what do you fly?
For almost 20 years I had annuals done at Ft. Collins Downtown and flew in there many times. I do some of my instrument practice at Loveland.

[N222AB]

Bill, I'm at FNL and we have a Baron. I've always wanted to build something, but it's just never bubbled up to the top of the priority list. So, I go to OSH and drool over the workmanship of other people. I heard the flying weather was nice today, but I was teaching a FAAST safety stand down today in Laramie. I drove (sigh...), but it's half an hour to the airport or an hour to drive to LAR. Maybe tomorrow.

My time slot is fixed now since it's set by the FAA guys managing the programs in their building. I hope you can set yours at a different time so folks who are interested can attend both presentations. I'd certainly like to meet you face to face and hear what you have to say.

[Bill Greenwood]

I mostly fly a Be36TC which is the next notch down from a Baron.
Yesterday was a great flying day and today was a nice one also at least in the am. I went out to the Boulder airport where the CAP was doing glider fights for cadets.

This afternoon we went to a Derby watching party and that part of the day was pretty good also, my girlfriend had the wining horse in the pool and won $36 which will pay for a few day's lunch at EAA.

[Mtns2Skies]

Here's a Mountain flight for ya:

https://vimeo.com/65535794