Backcountry Pilot • Airspeed vs. Altitude

Airspeed vs. Altitude

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Airspeed vs. Altitude

Original posting a couple days early. Packing light for motel tomorrow and surgery at oh dark thirty Friday.

Altitude long ago won the Airspeed vs. Altitude battle as the school solution for general aviation safety. This ushered in the two biggest probable causes in GA fatalities: unnecessary steep climb and the obsession with maintaining altitude in all maneuvering including low altitude maneuvering. "Vx or Vy as appropriate," which has mission drifted to mean always appropriate, assumes getting up to 1.000' quickly is safer than just topping the obstacle at the fastest airspeed possible. The result is that we have low time students and low time instructors mushing or stalling at 200' AGL a thousand feet down a long runway with a simulated 50' obstacle. Worse, we have indoctrinated the dangerous concept that getting up fast, and at Vy, is the safest technique. And the ACS indoctrination that we pull back on the stick in all turns develops very dangerous muscle memory.

Energy management has won a major milestone getting ACS to change to "acceleration in ground effect to Vx or Vy a appropriate. The problem now is that in 999 of 1.000 takeoffs tremendous extra energy is rejected by pitching to Vx or Vy thousands of runway feet before necessary to just clear the obstacles with the outcome of the maneuver never being in doubt. Rejecting this additional free, but not recoverable OGE, energy results in fatalities. DA makes this energy management failure even more deadly.

Once well over the obstacle, if any, the ACS indoctrination to remain at Vy, to remain on the razors edge, to continue seeking the bullet with our name on it, is deadly. The indoctrination that holding Vy pitch attitude is mathematically going to result in continuous Vy airspeed does not hold up in the natural world.

The airspeed vs. altitude argument is about energy management and is evenly balanced in mathematical theory. Airspeed is altitude and altitude is airspeed, the law of the roller coaster. The real life problem with the potential energy of altitude is that it takes good pilots a thousand feet of it to recover from inadvertent stall. Stall results from pulling back on the stick to go up or remain at altitude in a turn. Airspeed must be traded. Lack of airspeed to trade, while low, is deadly. When altitude is more important than airspeed, and we are below 1,000' AGL, we are in grave danger. We are operating under the wrong orientation and indoctrination for this environment so necessary for takeoff and landing. DANGER, wrong orientation/indoctrination.

So it seems logical that altitude is superior, safety wise, to airspeed above 1,000' AGL. This is appropriate high altitude orientation/indoctrination. It also seems logical, and fatalities confirm it, that airspeed is superior to altitude below 1,000' AGL. This is appropriate low altitude orientation/indoctrination. In the interest of safety, instructors let's orient/indoctrinate both ways. High flight is only possible after sufficient airspeed to not stall in the first one thousand feet. Those with the influence to establish orientation and to indoctrinate need to have situational awareness both high and low.

Optimism: There are things out there that we can do something about. Things like when low do not pull back on the stick as default for any maneuver. First establish zoom reserve in the form of airspeed.

Pessimism: It is rigged. There is nothing we can do about it. If we are taught to pull back on the stick in all turns, we have to pull back on the stick in all turns and we have to teach students to pull back on the stick in all turns. I have survived, they have to seek their own bullet with their name on it.

Optimistic teachers are more effective.
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Re: Airspeed vs. Altitude

Wait! I'm certainly not a mathematician and I think I have exposed myself to mathematical error. Since man is limited in his power to make thrust and gravity is not limited (correct me if wrong,) altitude is superior to airspeed energy wise.

Ok! In all turns allow the nose to go down naturally. That potential energy of altitude, when given up for airspeed, works like a charm. Zoom, zoom, zoom, zoom...even 200' of it.
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Re: Airspeed vs. Altitude

Like the designer went for dynamic stability, the pilot needs to muscle memory that maneuvering is dynamic. If we have zoom reserve (plenty of airspeed above what is needed to stay level, pitching up wings level is safe. The airplane is wanting to do that anyway. It doesn't like the gs of turning at high airspeed nor does it like Vne. So it is OK to pull back on the stick when we have zoom reserve. As soon as we decide to bank, however, we need to unload the wing by allowing the nose to go down naturally. This also must become muscle memory. So as a normal, design, part of turning (airspeed is going to change anyway) we need to think of the law of the roller coaster. Up wings level, bank and release back pressure at the same time. Down trading altitude into airspeed to make the turn safe.

Stall is only possible if we go static. If we insist on staying at the same altitude when we turn. Vne is only possible if we go static. If we insist on turning steeply from high airspeed and allow the nose to go down and stay down.

The energy management turn is dynamic, involving trading excess airspeed for altitude, banking at 1g by allowing the nose to go down as designed. Pull up before Vne.

No, it doesn't work going around and around and around in a level circle. Who does that? Why?
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Re: Airspeed vs. Altitude

I just watched Dan Gryder's recent video, "N880Z A Bad Way to Die." I am not a fast airplane driver, nor have I done many actual instrument circling approaches in Hueys. With fast jets like the circling approach at Truckee and this one, does something preclude my airspeed is more important than altitude at low altitude bias? If clouds prevent maintaining altitude anyway and if there is more than a thousand vertical feet to put the nose down into in the turn, what prevents a little energy management?

I am asking, not telling. You pilots who fly fast airplanes please explain why altitude must be maintained in the circling approach. Are circling minimums still in effect if N880Z cancelled IFR? Could he not have legally and safely allowed the nose to go down in the turn as the Lear was designed to do? The Lear was designed with dynamic neutral stability wasn't it?

I agree with Dan's DMMS but, for we who are totally math deficient and disorganized, why not just let the nose go down a bit as designed for dynamic neutral stability safety? Are turning aerodynamics different than for the 65 hp to 450 hp airplanes I flew?
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