Engine failure turn back.

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tallank

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We are talking a 2 second lag at a critical time
Throw in a few seconds lag for your scan and quickly changing bank angle during a busy time and
The aircraft does not change airspeed instantly. Something to do with momentum.
 

Pilot-34

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Did someone say it did ?
Do you care to define what you mean by instantly?
 

TFF

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If practicing autorotations on takeoff, the pitot static does not keep up with the abrupt change. It has to be instantaneous correction not read gauges.

If you are 10,000 ft over the Great Lakes, best glide is a good idea; plus you have plenty of altitude to play with it to get it spot on. Loosing an engine on takeoff means you have to fly the aircraft as though you had power. An evasive action like being shot at, but now you only have gravity powering you. Airspeed and control need to be priority. You only best glide when you have landing site made. Anything else, you are stretching glide and crashing is becoming more of a reality. If you are stretching glide early, you probably made a wrong choice unless its the only choice.

If you have some free airspeed, use it as long as you can. Cover some distance and use it for control. Once you slow down, you are pretty much stuck with corrections not direction changes.

You need to get past a point of student pilot rules of thumb KISS flying and start seeing how wide the envelope is. Start high and ease your way in. You are not going to figure it out in a weekend. Maybe a year of weekends. Then go do it at a different airport.
 

BJC

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We are talking a 2 second lag at a critical time
Throw in a few seconds lag for your scan and quickly changing bank angle during a busy time and
When I practice the return to the runway turn, I glance at the ASI 1 second after I pull power to confirm that the AS is close to the expected value, then don’t look at it again until I’ve completed the turn.


BJC
 

Dan Thomas

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Next time you take off watch the rate of climb. It takes minutes before it reaches its real number.
It does not. I was a commercial pilot and an instructor. Have an IFR rating. Taught Aircraft Systems in college. It takes a few seconds at most. Taking minutes would make it completely useless.

A variometer is a VSI with a small weighted piston in a cylinder that detects vertical accelerations and pushes or pulls air into or out of the VSI bellows to make it react faster.

Airspeed indications change very quickly. The principles of operation of the ASI and VSI are different.
 

BBerson

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The aircraft does not change airspeed instantly. Something to do with momentum.
Momentum is the mass plus the speed. Inertia is the resistance to that change in speed.
Yes, the aircraft does not change airspeed instantly but the pilot can indeed change the angle of attack before the required airspeed almost instantly with pitch by rapidly pulling the stick. The airspeed gauge lags after the pitch change because the aircraft speed lags because of inertia. But the aircraft angle of attack went beyond the critical stall angle almost instantly long before the momentum can increase to that needed speed and the change on the gauge indication.
In that time you are "sitting in a pile of junk" (quote Kershner).

"The worst possible move on your part would be to try to turn back" (quote Kershner)
 

Dan Thomas

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Momentum is the mass plus the speed. Inertia is the resistance to that change in speed.
Yes, the aircraft does not change airspeed instantly but the pilot can indeed change the angle of attack before the required airspeed almost instantly with pitch by rapidly pulling the stick. The airspeed gauge lags after the pitch change because the aircraft speed lags because of inertia. But the aircraft angle of attack went beyond the critical stall angle almost instantly long before the momentum can increase to that needed speed and the change on the gauge indication.
That's my beef with AoA indicators. They won't save your bacon if you pull hard enough to get an accelerated stall, and since the AoA indicator can't predict what you are about to do, by the time it yells at you you're stalled and in trouble.

Gimmicks cannot replace education. All the computerized gimmickry in cars now has dumbed the average dude down so he doesn't want to learn how to manage the aircraft engine. Doesn't understand what's going on up front. Everything gets learned by rote, with no real knowledge at all. It's why carb ice kills so many, why some are afraid to touch the mixture control, and why some can't navigate without a moving map and maybe an autopilot, too.
 

Daleandee

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That's my beef with AoA indicators. They won't save your bacon if you pull hard enough to get an accelerated stall, and since the AoA indicator can't predict what you are about to do, by the time it yells at you you're stalled and in trouble.

Gimmicks cannot replace education.
I have an ASI and a LRI (Lift Reserve Indicator) but my instructor was clear that there is nothing on the panel I need to see. The instruments are there to confirm what you should already know. Having said that I don't consider myself to be a great pilot, so I keep trying to get better at it ...
 

Vigilant1

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That's my beef with AoA indicators. They won't save your bacon if you pull hard enough to get an accelerated stall, and since the AoA indicator can't predict what you are about to do, by the time it yells at you you're stalled and in trouble.
I agree an AoA indicator can't foretell the future ("this guy is gonna pull hard and load up the wing in 5 seconds"), but it can absolutely tell you in real time how close you are to stalling the wing and the rate at which you are approaching a stall. Regardless of weight, bank angle, airspeed, etc, it will be correct in providing this information.
The "impossible turn" we have been discussing is similar, in some ways, to the turn "off the perch" in a military overhead pattern. You put the nose down to the proper attitude, roll into the bank, pull the plane around until you are lined up with the runway, have a short final approach and flare. In this turn, with some airplanes, the AoA indicator is a tremendous help in safely getting maximum performance from the wing during the turn. Yes, you should practice until you don't generally need it, but in a situation where the entry parameters may be nonstandard, an accurate AoA indicator could be a big help and much more useful than, say, an airspeed indicator.
 
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Dan Thomas

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Yes, you should practice until you don't generally need it, but in a situation where the entry parameters may be nonstandard, I think an accurate AoA indicator could be a big help and much more useful than, say, an airspeed indicator.
AoA is only one parameter. Coordination is also important, since a skid at minimum speed is asking for a spin. In some airplanes you can get a dangerous sink rate and that AoA will still be happy. Short-winged airplanes are famous for that. The stall-proof Ercoupe can get smashed on that runway if you get it too slow.

There are too many bad habits pilots often develop either during training or afterward. They really have no idea about stalls and spins, for instance. Too many keep thinking stall speed numbers from the POH without understanding that chart that shows increasing stall with bank angle. Load factor. It's what leads them to do the low pass over someone's house or the runway, then pull up hard in that supposedly spectacular zoom, sometimes adding a turn to it, and too often the airplane suddenly stalls and spins in before the pilot has any idea what's wrong. He somehow missed the accelerated stall stuff in groundschool.

The mind of an old pilot unconsciously process the G information from his bum in the seat and from the airspeed indicator to know when the thing is too close to stalling.
 

cdlwingnut

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if you are going to practice this and think you will actually use it, make sure to factor in the denial stage. The part where you go what was that, this isn't happening, ok its happening now what? every emergency I've had was nothing like an instructor going this broke or quit now what, It was what the fudge ok what do I know for dealing with this? so close the throttle count to 30 then start the turn.
 

Vigilant1

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(Bold added)
AoA is only one parameter. Coordination is also important, since a skid at minimum speed is asking for a spin.
AoA is only one parameter, but if we are just talking about stalling the wing, it is the only parameter that matters. Lots of us get in the habit of talking about "stall speed," and as you point out, too many pilots think that there's some speed that keeps the wing from stalling. We all are susceptible to talking this way, me, too. I suspect you even slipped into that mode above (bold). A skid at low speed doesn't cause a spin, it is an AoA exceeding the wing's critical AoA that causes a stall (somewhere), then uncoordinated flight results in a spin. Push on the stick (so the AoA doesn't exceed the critical AoA) and we might go right down to zero airspeed without stalling.
But, don't count on maintaining altitude.😉

It is useful for pilots to know about the relationship between bank angle and stall. As you point out, I think the (much) more important association in that case is between Gs and stall speed. But, that's not everything, either, obviously, since we can still stall the wing at one G. When it all comes together is when they internalize the fact that stall is only caused by the angle between the relative wind and the wing chordline-- AoA. The stick controls that.

Just my way of making sense of it..
 
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Dan Thomas

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AoA is only one parameter, but if we are just talking about stalling the wing, it is the only parameter that matters. Lots of us get in the habit of talking about "stall speed," and as you point out, too many pilots think that there's some speed that keeps the wing from stalling. We all are susceptible to talking this way, me, too. I suspect you even slipped into that mode above (bold). A skid at low speed doesn't cause a spin, it is an AoA exceeding the wing's critical AoA that causes a stall (somewhere), then uncoordinated flight results in a spin.
The skid introduces an AoA increase at the inside wingtip as the aileron goes down, and in many designs using little or no washout, that stall can happen before an AoA sensor farther inboard picks up on it, especially if the ailerons don't have differential movement. The upgoing aileron on the outside wing delays the stall.

Yes, it's the chordline relative to the airflow that's important, and lowering an aileron changes the outboard chordline quite a bit.
 

Vigilant1

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Dan,
Thanks. Yes, all true.

And, just to dot an "I", it is worth mentioning that critical AoA does change with Reynolds number, so that means it changes with airspeed. (This effect may not even be worth mentioning to new students, as it is highly likely to be confused with the incorrect idea that low airspeed causes a stall.
Later, in more advanced aero discussions, probably worth mentioning if they are clear on the basics). This effect is relatively small in practice and more important in a wind tunnel than to real world flying.

Mark
 
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Rhino

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...and why some can't navigate without a moving map and maybe an autopilot, too.
I often wonder what some people will do if the GPS constellation stops working for some reason. And if both GPS and the cellular network go down at the same time? Sheer pandemonium. But it'll probably be entertaining to watch, that is, until you have to go somewhere and all those idiots are just sitting still on the road because they can't figure out where to go. A young guy I knew recently had his wife lose her cell phone while she was out shopping at a new store. He had to go get her because she couldn't figure out how to get home. I thought he was pulling my leg, but he just said, "I wish".

As far as flying goes, it's my policy to still follow visual landmarks from my sectional charts when flying a GPS route. You can also read water towers and go IFR if needed (I Follow Roads). I've worked technology too many years to know that you should never rely on it to be there 100% of the time.
 
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BJC

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it's my practice to still follow visual landmarks from my sectional charts when flying a GPS route.
The beauty of moving maps in VFR flight is that one can, at all times, know where an available airport is accurately enough to have the magic go dark, and still be able to turn toward, and arrive at, that airport.


BJC
 

Hephaestus

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And... Honestly - running mountain passes vfr... Synthetic vision is a godsend.

Landmarks are great - but synthetic vision throwing you a whole screen of red ahead - gives you extra time to realize you made a wrong turn at Albuquerque.

Still important to ensure you have map/compass and e6b skills.
 

Dan Thomas

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And... Honestly - running mountain passes vfr... Synthetic vision is a godsend.

Landmarks are great - but synthetic vision throwing you a whole screen of red ahead - gives you extra time to realize you made a wrong turn at Albuquerque.

Still important to ensure you have map/compass and e6b skills.
I've wondered how long it will be before we read of an accident involving a pilot known to have a habit of flying through the Rocks in IFR using his synthetic vision. Knowing that GPS satellite signals can be blocked by surrounding peaks, I sure wouldn't attempt it. Someone surely will.
 
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