No bounce landing

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AuxBatOn
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Re: No bounce landing

Post by AuxBatOn »

photofly wrote: Sun Dec 15, 2019 9:40 pm In point of fact, you can read your AoA directly off the ASI if you know (or are willing to estimate) what your g force is.
Nope, i fly with a precise G-meter and still rely on the AoA indicator for precise and accurate AoA. I can feel approaching the critical AoA with how the aircraft feels (buffet and stick position) but not with ASI and G-meter alone. This allows me to look out (instead of in) and still have a very precise idea of where I am in relation to the critical AoA.
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AuxBatOn
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Re: No bounce landing

Post by AuxBatOn »

Straight from the US Navy Flight Test Manual 103:

The classical stall may be defined as a condition in which the airplane wing is subjected to an angle of attack greater than the angle for maximum lift coefficient. Stall speed can be defined as the minimum steady airspeed attainable in unaccelerated flight or the minimum usable airspeed. However, characteristics exhibited by many airplanes in the region of the stall preclude attainment of the classic aerodynamic stall. These characteristics vary widely among different airplanes and are greatly affected by a multitude of factors.

Also, give 2.2.7 a read...

http://www.usntpsalumni.com/Resources/D ... TM_103.pdf
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photofly
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Re: No bounce landing

Post by photofly »

I do not deny that experience with flight on the edge of a stall, and through a stall, is extremely valuable, as the experience differes for different types, and for different ways the stall is reached on the same type.

Nevertheless, the definition of a stall doesn't depend on the response of a particular aircraft on a particular day, and recognizing a high angle of attack can still be done without knowledge of or reference to expertly written type-specific documentation.
Nope, i fly with a precise G-meter and still rely on the AoA indicator for precise and accurate AoA.
That is marvellous. It is still true that in aircraft without a AoA indicator and without a G-meter, which is almost all of them, you can appreciate your AoA at any given g-force by looking at the ASI.

Gaining a feeling for AoA should not be taught as something that requires reading a flight manual or having a special indicator to read it on. It's more fundamental than either of those things, valuable as they are.
Do you think that if they had recognized the symptoms of a stall on their aircraft, the Air France pilots over the Atlantic would have stalled and maintain pro-stall inputs for more than 35,000 ft to their death?
I think if they had been able to recognize a high AoA on *any* aircraft, by the way I described, even if they had never before sat in the cockpit of an Airbus, they would have saved a bunch of lives. Because they were concentraing on symptoms, rather than on basics, they didn't recognize the stall. Nobody should ever say to themselves, "I am unable to recognize a stall in this aircraft type because I've forgotten what the manual said the symptoms are."
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AuxBatOn
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Re: No bounce landing

Post by AuxBatOn »

So, tell me, what is an excessive AoA, in practical terms, as defined by looking inside? Assume you are IMC.
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photofly
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Re: No bounce landing

Post by photofly »

You’re a very smart guy: you can list as many ways to recognize a high angle of attack as I can, both by looking inside, by looking outside, and often by control feel too.

I don’t believe for an instant that you think recognizing a stall can only be done, or must be done, after consultation with the flight manual, so I’m not sure why you’re arguing.

Going back to the point of this thread, we can both recognize (well, Captain Underpants did, let’s give him credit - I needed prodding) that the aircraft in the video appears to have had an angle of attack that was too high for a safe landing, using less information than the pilot had in from of him/her, and I’ve never sat in a Seminole, still less read the flight manual of one.
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corethatthermal
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Re: No bounce landing

Post by corethatthermal »

What we know : The pilot shut down both engines but failed to feather the props, then decided not to restart . NOW, the pilot finds he is barely making it to the airport and so he tries to find a speed for best glide.... Unfortunately, that speed is in a low energy state with no energy to flare and I think he knows that. I suspect that he didn't aggressively try to flare because he knew he would "stall" the plane and cause injuries. ( If his energy state/airspeed was low enough, flaring would have INCREASED the rate of descent )
Obviously, on approach, the planes wing was not "stalled" He was basically just on the backside of the power curve without the required thrust to make a successful flare. IF he was well into the backside, then he would need thrust to SLOW down more!
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Re: No bounce landing

Post by corethatthermal »

Looking closely at the video, it appears he tried twice to test the aircraft WRT its response after a pitch-up and as we can see, it was worse than he likely expected and so therefore he didn't try to flare, he already knew what would happen because he already tested the A/C energy state on approach!
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Ki-ll
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Re: No bounce landing

Post by Ki-ll »

AuxBatOn wrote: Sun Dec 15, 2019 11:00 pm So, tell me, what is an excessive AoA, in practical terms, as defined by looking inside? Assume you are IMC.
Would stick/control column deflection be a good enough indicator?
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digits_
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Re: No bounce landing

Post by digits_ »

corethatthermal wrote: Mon Dec 16, 2019 9:19 am Obviously, on approach, the planes wing was not "stalled" He was basically just on the backside of the power curve without the required thrust to make a successful flare. IF he was well into the backside, then he would need thrust to SLOW down more!
If photofly's data is correct, the was damn well as far into the backside as he can get. No you don't need thrust to slow down more. He was descending. He would just be descending steeper, which I think is exactly what happened, as the video seemed to show.

If he was maintaining his regular approach speed, which is just around the negative peak in the power curve, he would have had enough energy to at least attempt to flare.
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AuxBatOn
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Re: No bounce landing

Post by AuxBatOn »

Ki-ll wrote: Mon Dec 16, 2019 9:50 am
AuxBatOn wrote: Sun Dec 15, 2019 11:00 pm So, tell me, what is an excessive AoA, in practical terms, as defined by looking inside? Assume you are IMC.
Would stick/control column deflection be a good enough indicator?


If you re-read some of my earlier post, stick/control column can be used as a stall definition.
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digits_
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Re: No bounce landing

Post by digits_ »

AuxBatOn wrote: Mon Dec 16, 2019 11:57 am
Ki-ll wrote: Mon Dec 16, 2019 9:50 am
AuxBatOn wrote: Sun Dec 15, 2019 11:00 pm So, tell me, what is an excessive AoA, in practical terms, as defined by looking inside? Assume you are IMC.
Would stick/control column deflection be a good enough indicator?


If you re-read some of my earlier post, stick/control column can be used as a stall definition.
That is a terrible stall definition. I can be stalled or unstalled at any control column position/deflection. It highly depends on the context, or how you ended up in that position. But if you knew that, you probably wouldn't be trying to figure out if you are in a stall...
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iflyforpie
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Re: No bounce landing

Post by iflyforpie »

Your AoA indicator on most aircraft is the stall warning vane. Or buffet. They work at any weight, any configuration (though some aircraft have to have multiple vanes for different flap settings), any speed or wing loading. They don’t always work when a plane is iced up.. but neither will an AoA vane, either.

It won’t tell you other angles of attack.. like for best climb or glide. For most aircraft these are done at 1G and airspeed is close enough for those.

It’s also worthy to note that AoA won’t solve everything. If you’re low, below your aircraft’s 1G stall speed, but maintaining an AoA for best L/D... you’re probably going to hit the ground violently. ;)

With AF447... you had a pilot who had lost control of the aircraft and was “going back home to momma” hoping that Alpha Protect and Alpha Floor would help him climb again just below the critical angle of attack while commanding increased engine thrust... not realizing those had been disabled after the aircraft had reverted to Alternate Law. The aircraft was in such a deep stall that the AoA vane no longer registered a stall... and any relaxation on the side stick would cause the stall warnings to sound—completely opposite of what you’d expect. Compounding the issue was the lack of tactile feedback on the left side stick and the inattention of the PM to the position of the right stick.
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Re: No bounce landing

Post by Ki-ll »

digits_ wrote: Mon Dec 16, 2019 12:04 pm
AuxBatOn wrote: Mon Dec 16, 2019 11:57 am
Ki-ll wrote: Mon Dec 16, 2019 9:50 am
Would stick/control column deflection be a good enough indicator?


If you re-read some of my earlier post, stick/control column can be used as a stall definition.
That is a terrible stall definition. I can be stalled or unstalled at any control column position/deflection. It highly depends on the context, or how you ended up in that position. But if you knew that, you probably wouldn't be trying to figure out if you are in a stall...
I’d disagree. Airplane would stall at roughly the same stick/control column position most of the time. So if you find yourself pulling hard back on the controls you should know that you are close to the stall.
While the best and a most precise indicator of the stall would be an AoA indicator even having one in front of you won’t prevent a stall.
This crew wasn’t saved by it and Tu-154 has an indicator, flasher and an aural warning.
https://en.m.wikipedia.org/wiki/Pulkovo ... Flight_612
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digits_
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Re: No bounce landing

Post by digits_ »

Ki-ll wrote: Mon Dec 16, 2019 2:34 pm
I’d disagree. Airplane would stall at roughly the same stick/control column position most of the time. So if you find yourself pulling hard back on the controls you should know that you are close to the stall.
Following that traing of logic, if full aft position of the controls equals "stall", why does the manufacturer allow pilots to move the controls fully aft? Why not limit the control to the "not stalling" range?
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AuxBatOn
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Re: No bounce landing

Post by AuxBatOn »

digits_ wrote: Mon Dec 16, 2019 12:04 pm
AuxBatOn wrote: Mon Dec 16, 2019 11:57 am
Ki-ll wrote: Mon Dec 16, 2019 9:50 am
Would stick/control column deflection be a good enough indicator?


If you re-read some of my earlier post, stick/control column can be used as a stall definition.
That is a terrible stall definition. I can be stalled or unstalled at any control column position/deflection. It highly depends on the context, or how you ended up in that position. But if you knew that, you probably wouldn't be trying to figure out if you are in a stall...
For 1g, it may be all you get, beyond artificial stall warnings.
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Re: No bounce landing

Post by PilotDAR »

Typically, elevator control against the pitch up control stop may be one indicator of a stall. This is permitted by the design requirements. It is one of several possible conditions where the pilot no longer has control to raise the nose, which should be the more broad indicator of a stalled condition. If the nose won't go up any more, or you cannot prevent it going down, the plane is stalled.

While flight testing a modified Roberston STOL Cessna 206, I demonstrated to the Transport Canada test pilot who was accompanying me that day, that the slowest speed at which I could fly varied between 42 and 37 KIAS. This was with the control wheel held fully back at forward C of G. I inquired of him as to what we would define the stall speed as being in IAS. He asked me if I could control the flight at 37 KIAS - no I could not, it bobbed there itself, I could control at 42. So 42 KIAS was the stall speed, because although it would bob to a slower speed, then speed up a little again, I could not control that motion, other than to recover the stall, and fly faster than 42 KIAS.

However, a plane which may have controls at the stop as a stall indicator in one configuration, may certainly aerodynamically stall in other configurations (C of G and flap position, in particular). There were a few planes (Ercoupe) for which elevator at the stop was always the stall indication - but then the Ercoupe had a rather narrow C of G range, so it worked. The manufacturer won't give you any more elevator control than is shown to be needed for control in all situations, but they must give you enough control, so that may be a little more than you need to stall in some configurations.
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Ki-ll
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Re: No bounce landing

Post by Ki-ll »

digits_ wrote: Mon Dec 16, 2019 3:49 pm
Ki-ll wrote: Mon Dec 16, 2019 2:34 pm
I’d disagree. Airplane would stall at roughly the same stick/control column position most of the time. So if you find yourself pulling hard back on the controls you should know that you are close to the stall.
Following that traing of logic, if full aft position of the controls equals "stall", why does the manufacturer allow pilots to move the controls fully aft? Why not limit the control to the "not stalling" range?
I am not sure that’s the same train of logic.
There are situations where you might need that control deflection which goes beyond the “stalling position” of the controls albeit momentary. Holding it in full aft is different than going to aft stop when you need it.
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Re: No bounce landing

Post by digits_ »

The problem with defining a stall like that -ignoring for a moment that it is factually incorrect- is that it simplifies matters too much. Let's say you teach a student like that. He might be afraid to use full control deflections when necessary, because full aft apparently means the plane is stalling.

Teach pilots what a stall actually is. Angle of attack that exceeds the critical angle. Ok, great. Now how can you recognize that? Multiple options, stall warnings, AoA vanes if installed, you might feel buffetting, the controls will feel different, unable to hold altitude ... Cool. But you can also be stalling without any of those things. Warnings can be broken, your yoke could be almost centered, you might think you are climbing instead of falling down, etc.

Then teach all those possible options. If you dumb it down to "full aft means you are stalling", you will not be doing your students any favors.
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Re: No bounce landing

Post by Ki-ll »

That’s a fair point.
Defining a stall via stick position is not correct.
I was talking more among the lines of what pilots have readily available to them in the cockpit to determine how close they are to a stall.
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iflyforpie
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Re: No bounce landing

Post by iflyforpie »

There’s also definite cases where full aft is not stalled.

Pipers were notorious for this—especially the T tail Seminole where the stabilator is out of the prop wash. Get too slow and you’re at full deflection and can’t pull the nose up. That’s why you tend to fly spam can Pipers on instead of stalling them on like a Cessna.

The Cessna 206 was also like this if it was at the fwd limit. I’d land with full aft input all of the time and the wing was nowhere near stalling. Usually a bit of power on touch down helped it out.
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