Backcountry Pilot • Loss of Maneuverability

Loss of Maneuverability

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Loss of Maneuverability

The FAA is concerned with loss of control, LOC accidents. If we back up to before stall/spin, we experience mush. And before mush, we have a short or even long period of kinetic zoom reserve deterioration. All of this results from our pulling back on the stick in hope of climb or greater rate of climb or even faster level or climbing turn rate.

Helpfully, since 2013 flight test standards change, we are expected to accelerate in ground effect to Vx or Vy as appropriate on takeoff. In less than perfect conditions, however, Vx or even Vy can deteriorate to the mush condition. And neither Vx or Vy as appropriate is what Wolfgang called zoom reserve. Maintaining zoom reserve, and thus maneuverability, is more important than gaining altitude quickly.

Zoom reserve requires enough airspeed, level or climbing, to easily maneuver at any bank angle briefly. Maintenance of zoom reserve in any bank will require our lowering the pitch angle by releasing back pressure. Airspeed can be traded for altitude and altitude thus gained can be traded for airspeed as needed. Dogfight quality maneuvering is safely possible using the thrust of modest engines and energy managed airspeed and altitude. Getting to altitude patiently retains zoom reserve.

Because big engines are popular, airspeed developed from engine thrust is readily accepted, and unfortunately expected. Tremendous potential energy of altitude, becoming kinetic energy of airspeed if we just allow the nose to go down naturally in the turn, is not as popular and is less utilized in a crisis. Utilization of vertical space available may be Greek in most flight schools, but it has tremendous potential in mitigating or overcoming LOC. We don't need stall practice altitude. Started early enough while still able to maneuver, before loss of maneuverability, fifty feet of altitude can give us a real kick in the pants.

Things don't always go as planned, but we are pilots. We are in control. Unlike skydivers, we do not require at least 600 feet of vertical space available to maneuver efficiently. We need only one foot over obstacles and terrain. If we are at Vx and mushing, pitching further up is only going to make it worse. If we can't give up enough back pressure to make a safe turn at the bank angle necessary to miss the tree, we should try to hit the tree and zoom one foot over the tree. Over the tree we can level the nose and perhaps even pitch down into the drainage.
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Re: Loss of Maneuverability

+1
a3holerman offline
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Re: Loss of Maneuverability

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soaringhiggy offline
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Re: Loss of Maneuverability

It has been a fortnight since my last original post and I haven't had an epiphany. In light of recent accidents, I decided to revive consideration of loss of maneuverability.

Flight schools and instructors are required to teach stall recovery and I think going back to the dump the nose technique in a recent video is the best technique. In the area of stall prevention, however I would rather see emphasis on maneuverability. Again the video instructor had a good idea with the tape on the airspeed indicator. I would also emphasize relative wind noise, buoyancy, stick position, etc.

Finally, too few other than crop dusters and pipeline patrol pilots have low altitude orientation. That comes with experience, but we could do a better job of making those who operate above 1,000' AGL aware that low altitude orientation is necessary on takeoff and landing. The school solution of Vx or Vy as appropriate has not been helpful. Maneuvering speed, like the taped speed on the video instructor's airspeed indicator, is appropriate. Vx or Vy is appropriate only when necessary to get us a few feet over the obstruction.
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Re: Loss of Maneuverability

As always Contact, right on point.

I want to highlight the point about relying on the sounds. I do think the advent of headsets being standard in the cockpit (this happened well before my time) and then the further advent of the ANR headset have really shifted many pilot's mental picture of the situation away from one that relies on the ambient sounds of the airframe. It can be a tremendous tool for sensing the situation of the aircraft, especially at the higher angles of attack at low power where airframe sounds are more perceptible.

As a matter of proving this theory, I regularly, when traffic is light, will make a pattern or two without the headset on; minimal reference to the gauges. The result? Usually some of the nicer on-point landings I have made. Off airport ops where I know radio coms are pointless I frequently do without the headset to better hear the airframe noise and hear for unexpected damage from debris.

We can train ourselves to perceive many subtle signs from the aircraft as Contact pointed out. It's quite true the value you can get from some very primary flight training in things like a basic S-233 glider or a properly underpowered J-3 is invaluable. Decouple success from the powerplant and you'll find you can fly with a lot more margin than you realized.

One historical aside. Read up on training in WWII in Stearman where the concept of "singing of the flying wires" is often romanticized. But really that was an essential part of the training to be able to land a big brick of a glider like a PT-17 by hearing the changes in the airframe as the speed bled off. It's an absolute hoot to do too.

Fly the wing. Don't SSCBD. (Stall Spin Crash Burn Die)
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Re: Loss of Maneuverability

Yes, with the sound of a happy wing, zoom reserve in airspeed, Vy or even Vx pitch attitude is appropriate...temporarily.
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