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Flying up narrow canyons

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https://www.mountainflying.com

Sparky Imeson devotes considerable content in Mountain Flying Bible to the subject of turning around in narrow canyons. I don’t plan to paraphrase the content but would recommend strongly anybody interested in flying in the mountains to buy his book.

He warns against chandelles, wingovers, or hammerhead stalls because there is a human tendency when encountering rising terrain to shorten your flying arm and start to slow down. There is also density altitude, downdrafts, etc to contend with.

Basically he recommends establishing a point of no return, and describes how to establish this.

He also recommends training to ensure your technique is a conditioned response. He discusses what side of a canyon to fly (downdraft or updraft side?); the basic maths of turn radii vs speed vs configuration vs angle of bank vs g-load, and what is the ideal technique for the turn.

I think the main value of his advice is in the behavioural and physiological factors associated with flying in the mountains. Unlike the FAA CPL a chandelle or wingover (which is technically an aerobatic manoeuvre) in the mountains has very different visual cues to the nice PowerPoints showing the manoeuvres over the flat plains of Kansas or Iowa with visibility at infinity. In these conditions you have a clear horizon, there is no startle effect, you have carried out a HASELL check with plenty of altitude, you are not even in an aerobatic competition box so no need to consider wind (the FAA ground proximity manoeuvres do require consideration for wind), and you are starting from an appropriate entry speed.

In a box canyon you have allowed yourself to ‘box yourself in’, the aircraft is at a high density altitude, one side is in deep shade, one side is in haze and glare, one side has downdrafts, one side updrafts, turbulence, there is NO DISCERNIBLE HORIZON, you are surrounded by rocks – Imeson’s point being that you don’t want to have an instinctual response, but you should have a knowledgeable, planned response in a manoeuvre you have trained for and are current in.

I do think the FAA CPL is superior to the EASA version by virtue of the ground reference and co ordination manoeuvres, but I wouldn’t recommend a chandelle or wingover as the desired conditioned response if you are caught out in a narrow canyon.

Oxford (EGTK), United Kingdom

I’m struggling to see your exact point?

Practicing min-radius turns is a good one. Then incorporating them in an emergency turnback. Bleed airspeed for height, until just onto the buffeting, or stall horn coming on then keep the Angle of Attack there until 180degrees opposite direction. You have to practice this with an instructor who knows what he is doing and can explain to you what is happening.

I learned to fly in British Columbia so early on spent time in high density altitude locations and flying in the Rockies.

My point is that there are good books giving a comprehensive picture of how to fly in the mountains. No one that I am aware with mountain flying experience, and in Europe I spent time in northern Italy with experienced mountain flying instructors, would recommend manoeuvres that approach the stall, let alone buffet, as a good practice.

The chandelle in effect is a climbing turn that turns 180 degrees and at its conclusion is approaching the stall. It is a good exercise in energy management and coordination, but it was not intended to extricate yourself from a narrow canyon.

I hope those planning to fly in the mountains try and get a copy of a good primer, such as Imeson’s, or get training from a qualified instructor in France or Italy.

As mentioned elsewhere not all types exhibit buffet, and a stall warner, if fitted, should be sounding well before the onset of buffet. There are other symptoms of a stall in addition to buffet and stall warner. The turn recommended in a narrow canyon is very different to a chandelle.

Oxford (EGTK), United Kingdom

I also learned to fly in British Columbia. My instructor and a CPL student (who already had a PPL) died as result of a botched canyon turn practice maneuver.

An instructor who checked me out on a new to me floatplane is also dead. Possibly a gusty crosswind swirling around the mountains and/or a small island.

I believe there is also some uncertainty about Sparky Immeson’s death (from a crash) but it might have been a pitch-up and wing over scenario at low altitude.

I think the takeaway from Robert’s comments is fourfold:

  1. It excellent to learn as much as possible about flying in the mountains, read the book.
  2. You should know the limits of your airplane. Practicing maneuvers at safe altitude with circumspection (with many thousands of feet to recover) is probably helpful, e.g. I didn’t really know how tight my airplane could turn until well after my PPL. I don’t think most PPLs (at least the ones I know) have experienced a sharp wing drop to the outside in a minium radius turn. If this happens to you for the first time at low altitude you are dead!
  3. Practising near stall maneuvers at low level is a terrible idea. I make it a hard rule that I am never manuevering at low level while slow. For example, my Champ might have stalled at 40 mph. Multiply by 1.41 for a 60 degree bank and you get 56 mph (I would try not to exceed 15-20 degrees at low level). If you never maneuver below 75 mph, then you have at least 35% buffer over your worst case bank (of 60 degrees). Now of course you have to make sure you are coordinated and your speed doesn’t bleed off during a turn, but this is what your mentor/instructor is for (plus practice, plus currency).
  4. Why are you in a canyon that tight in the first place? Be aware and get out early!

This is a good discussion, but a PPL is mostly on their own after they get their license. I think you have to be pretty prudent and regimented to learn about the full flight envelope in a safe manner. Getting a mentor is a great idea.

Off airport and mountain flying is unbelievable awesome. But think about it beforehand and be prudent!

Last Edited by Canuck at 26 Apr 11:53
Sans aircraft at the moment :-(, United Kingdom

This is one reason to be really careful… Curiously I recall reading about a similar one where 3 planes crashed all together, but perhaps it was the same one which was incorrectly reported.

Administrator
Shoreham EGKA, United Kingdom

Canuck my training was at Vancouver and Pitt Meadows, including in a Fleet Canuck! This was over forty years ago I fear. Nice short IR in a Seneca 1: Vancouver to Tofino for the NDB and then back to Vancouver for the asymmetric ILS. The Fleet Canuck was a nice type and seemed to only require one hour of check out so very benign.

Edited as auto spell put Torino instead of Tofino!

Last Edited by RobertL18C at 26 Apr 17:34
Oxford (EGTK), United Kingdom

Robert,
Sounds like you had a great time. I haven’t flown a Fleet Canuck, but it seems like I should one day. I am minded to seek out a Fleet Finch though (which is open cockpit biplane)… living in the UK, I guess a Tiger Moth is the correct substitute!

I learned to fly out of Boundary Bay, but my float plane was based at Pitt Meadows. For a trip down memory lane, I have attached picture from just north of the airfield, looking up to Pitt Lake. It probably didn’t look too much different when you were there (perhaps without the small golf course in the foreground?). All very lovely!

BC is a great place to fly, I look forward to doing more flying there at some stage. Then again, the UK and Europe are also pretty scenic. So many places, not enough time :-).

Last Edited by Canuck at 26 Apr 22:45
Sans aircraft at the moment :-(, United Kingdom

And a narrowish valley to bring things back on topic! Also, the last shot is from a super bright moon!




Last Edited by Canuck at 26 Apr 22:56
Sans aircraft at the moment :-(, United Kingdom

@Canuck – NIIIICE !!!

Ah… Pitt Lake.. I did my mountain training there in the helicopter. It was while practicing toe in landings on a mountain slope up at the north west of Pitt Lake that I had a revelation. I was toeing in on a grassy/rocky slope, and it was very difficult to maintain my sense of up. as I approached the slope, my fixed wing response was to pull up away from ground I was approaching at around a forty degree angle. In the helicopter, pulling “up” on the cyclic will result in backing away from the slope – safe, but objective not met. I finally recognized that the small trees were my cue, they piloted up, so I could use them as a reference. With that reference, I could toe in. I sat there with the skid toes pressed against the slope, and looked around – rock/grass/small trees – no horizon. It was a clear day, but the horizon was several thousand feet above me, and certainly not in the plane of view out most airplane windshields. The MD500 offered an excellent view, so I took time to appreciate this new visual sensation.

The revelation was the background of an accident several years earlier (http://tsb-bst.gc.ca/eng/rapports-reports/aviation/2006/a06p0087/a06p0087.pdf local copy ) in which the pilot I had trained lost it in a canyon, and crashed into the side. Though a smaller canyon, in the area he crashed, there was still room to maneuver, and exit safely – if you maintained your reference. I opine that he turned, and during the turn, lost a reference to up, seeing only trees and rocks all around, but not having time to discern where up was, so as to recover the turn. The possibility that he was taking photos did not help with situational awareness.

So the result was a fatal accident, and far reaching repercussions. So, now, when I teach confined area maneuvering, it will include a steep climbing turn. With enough practice on type, a pilot should be able to enter and maintain a climbing turn with thirty to forty degrees angle of bank. If the turn was entered at cruise speed, there will be inertia to trade for altitude. The other trick is to extend some flap in the turn. This will increase lift at the cost of speed, making a smaller radius turn. As long as it is a 180 degree turn, you can afford to be pointed out of the canyon, with a bit more altitude, and a bit less airspeed, as long as you’re oriented, and able to recover to safe flight again. If you need to descend a little to do that, it should be okay, as you should be headed toward lower ground.

Awareness, and practice. The Norway VFR guide book also has some good advice about this.

And, watch for wires! (You can just see the yellow warning balls, I went under with great care!)

Home runway, in central Ontario, Canada, Canada
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