Good Pilot/Bad Pilot

[phoenixlpr 0]

I was listening the stall horn yesterday much...........

I dont think its the right way to climb.

[LearningTOfly 0]

Uh guys, would you like to go up in that 206 on a hot (humid) summer day with five in the back at anything close to a reasonable rate?

Let the pilot do his job- he knows what he's doing- the stall horn is going off, most likely at low altitude just after takeoff, because el capitan is trying not to cream the plane and it's contents into the fence/ trees/ etc at the end of the runway. If you're so worried he can't do his job properly, or that the day is too hot or humid to fly safely, talk to your DZO.

[AggieDave 6]

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Let the pilot do his job- he knows what he's doing- the stall horn is going off, most likely at low altitude just after takeoff, because el capitan is trying not to cream the plane and it's contents into the fence/ trees/ etc at the end of the runway.

Huh... Had you thought that what happens to a single engine cessna close to the ground flying at or near stall speed if the engine quits? It stalls, in the stall the tail drops, the plane rolls to its back and everyone dies as it pancakes in.

Now, have you wondered WHY there is a stall horn?

Also, have you wondered what other conditions would cause that situation, maybe due to a weight and/or CG issue?

These are very important things to ask your pilot about. Learn about your jump aircraft, it'll make you a safer skydiver (and help keep you out of questionable situations).

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[LearningTOfly 0]

Just because the engine quits does not mean, by any stretch of the imagination, that a plane must stall. Angle of attack is the only thing that will produce a stall. Exceed (about) 16* AOA, and the wing will stall.

In a stall, again, nothing says the tail drops. Provided the aircraft is properly loaded, it is designed so that the nose will drop (that way the pilot may recover in a non-exciting manner).

I think that the bigger concern would be clearing the trees at the end of the runway after convincing your pilot to fly without the stall horn going off. Connecting with powerlines or trees will be slightly more annoying than listening to a buzzer for a few seconds.

Why is there a stall horn? Good question... the planes I fly have no stall horn. A good pilot can feel how the craft is flying and can judge his speed off of that feel- cross checking the ASI is sensible also- keep it in the green arc, don't do anything to change the AOA quickly, and a stall will not result. Stalls are not surprizes- they happen under certain known conditions.

If a CG issue causes the stall, then the pilot holds the responsibility for flying an aircraft with the CG out of tested datum locations. If I'm not mistaken, in this case, the 206 would be properly classified as experimental and your pilot will have just been promoted to 'test pilot'. Insurance would also no longer be vaild as the aircraft is operating outside the limits specified in the POH.

These are things I have asked myself about, yes- and I know the answers...

Blue Skies

[chutem 0]

I guess I don't understand stalls as well as I thought. I always thought that airspeed was a factor in stalling an aircraft. Is the stall horn there to protect the manufacturer from lawsuits or to warn you that your pushing the limit. (maybe both) You have to remember that Dave has had a loss of power on takeoff situation in a cessna in the past and it might not have turned out so well if the pilot was "pushing the limit" when the engine failed.
James

[phoenixlpr 0]

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Is the stall horn there to protect the manufacturer from lawsuits or to warn you that your pushing the limit.

I think its just an indicator that the plane has reach stall speed.

Are you a lawyer?

[n23x 0]

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Just because the engine quits does not mean, by any stretch of the imagination, that a plane must stall.

You're right, but when you are intentionally flying in conditions that put you close to a stall, relying on the engine to haul you through that, especially low to the ground, is a poor choice.

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In a stall, again, nothing says the tail drops. Provided the aircraft is properly loaded, it is designed so that the nose will drop (that way the pilot may recover in a non-exciting manner).

Properly loaded. What percentage of jump planes do you believe are always properly loaded? What percentage do you believe aren't?

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I think that the bigger concern would be clearing the trees at the end of the runway after convincing your pilot to fly without the stall horn going off. Connecting with powerlines or trees will be slightly more annoying than listening to a buzzer for a few seconds.

We're not talking about listening to the stall horn go off for a second or two on takeoff roll. We're talking about listening to it the whole way up, with the plane buffeting around. You know, that feel you're talking about a good pilot knowing?

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Why is there a stall horn? Good question... the planes I fly have no stall horn. A good pilot can feel how the craft is flying and can judge his speed off of that feel- cross checking the ASI is sensible also- keep it in the green arc, don't do anything to change the AOA quickly, and a stall will not result. Stalls are not surprizes- they happen under certain known conditions.

Even the best pilots can become task overloaded. An audible indicator isn't a bad thing.

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If a CG issue causes the stall, then the pilot holds the responsibility for flying an aircraft with the CG out of tested datum locations.

Once again. What percentage do you believe are properly loaded and appropriate CG range. What percentage do you believe are overloaded and are near/exceed CG limits?

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These are things I have asked myself about, yes- and I know the answers...

Pushing the limits can be a good thing. Continually pushing the limits of a heavily loaded aircraft that has a constantly changing CG is NOT a good thing.

Dig through the past years incident reports and look over the multiple instances of small aircraft stalling on takeoff. Do you think that keeping the airplane on the verge of a stall in an attempt to max out climb contributed to the subsequent stall and crash of these aircraft?

It probably did.

What we need from our jump pilots, among other things, is a conservative takeoff/climb to recoverable altitude.

.jim

"Don't touch my fucking Easter eggs, I'll be back monday." ~JTFC

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[LearningTOfly 0]

Airspeed actually isn't a factor in a stall. Granted, the wing must be flying (L=W) or travelling close to the required velocity for lift to equal weight. After that, it's the flow over the top of the wing that causes the stall- at high angle of attacks, the point at which the flow turns from laminar to turbulent moves forward up the chord. At a certain point, the drag produced in this turbulent separation is so great that the wing (plus powerplant) cannot maintain the aircraft in level flight anymore. This turbulent separation can be loosely compared to the burble in freefall- for comparison, bellyflight is a stalled condition.

Also, a stall may be encountered on a single aircraft at a range of speeds from vso (say 55 kts) to va (say 130 kts) It all depends on how aggressively the AOA is changed and whether it exceeds 16* AOA in that change attempt.

[AggieDave 6]

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You have to remember that Dave has had a loss of power on takeoff situation in a cessna in the past and it might not have turned out so well if the pilot was "pushing the limit" when the engine failed.

I'm glad you remembered that.

4 years earlier at the same airport with a different DZ, a similar incident happened, EXCEPT, the pilot was pushing the limit with climb angle and stalling on take off. All 5 of those people died and we now have a memorial boogie for them.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[tombuch 0]

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I think that the bigger concern would be clearing the trees at the end of the runway after convincing your pilot to fly without the stall horn going off. Connecting with powerlines or trees will be slightly more annoying than listening to a buzzer for a few seconds.

We're not talking about listening to the stall horn go off for a second or two on takeoff roll. We're talking about listening to it the whole way up, with the plane buffeting around. You know, that feel you're talking about a good pilot knowing?

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Why is there a stall horn? Good question... the planes I fly have no stall horn. A good pilot can feel how the craft is flying and can judge his speed off of that feel- cross checking the ASI is sensible also- keep it in the green arc, don't do anything to change the AOA quickly, and a stall will not result. Stalls are not surprizes- they happen under certain known conditions.

My commercial pilot training is a bit rusty, but I don't understand why the stall horn should ever be making any noise on climb out. With a single engine airplane like a C-182 the idea is to climb at Vx until clear of the hazards at the end of the runway, then climb at Vy. The stall horn is set at a much lower airspeed than Vx. You might hear the horn just after rotation while building speed in ground effect, especially on a soft field take off, but the climb out should be horn free.

The idea behind Vx is that it is the airspeed that will give the greatest climb performance over a given distance. Vy gives the greatest climb over time. Any airspeed below Vx gives less climb performance than Vx. If the pilot is climbing with the stall horn making noise, it seems he will be below his best climb airspeed, and will thus be sacrificing performance. So, he would climb better at a higher speed (Vx).

It's been a while since I hit the pilot training books, but am I missing something?
.

Tom Buchanan
Instructor Emeritus
Comm Pilot MSEL,G
Author: JUMP! Skydiving Made Fun and Easy

[chutem 0]

Not a Lawyer, just trying to understand why the stall horn is there if it is not telling you something you "need" to know. I know litigation has had harmful effects to the private aircraft manufacturers and wondered if this is a cover your ass type warning.
James

[mjosparky 4]

An airplane can be put in a stall condition at any airspeed and at any power setting. It has to do with the wing producing or not producing lift.

The stall warning horn on a Cessna is a small free floating tap on the leading edge of the wing. In normal flight the relative wind holds this tab in a down position. If the angle of the wing exceeds a given degree to the relative wind, the tab is pushed up by the wind. This closes a circuit and the horn goes off. When climbing in turbulent air the bouncing of the aircraft can cause this tab to flutter even when a stall is not eminent.

If you fell the pilot is flying in an unsafe manner, and make sure of your fact first, say something to the DZO and refuse to fly with him/her. Complaining about it on dz.com will not change the situation.

Sparky

My idea of a fair fight is clubbing baby seals

[chutem 0]

Let me understand, are you saying that an aircraft is not more likely to stall at a lower airspeed than at a higher airspeed with the same AOA? I have to assume that an engine failure will reduce airspeed. I do not know what the affect on the AOA will be.
educate me please,
James

[chutem 0]

Thanks, that helps explain why hearing the horn does not mean your flying on the edge. Still curious about the airspeed thing. Is an aircraft more likely to stall as the airspeed reduces?
James

[n23x 0]

All I know is that we've had many times in which the stall warning horn has been going off seemingly continuous for a great deal of time after takeoff roll. If it was due to turbulent air, then so be it. However, whenever this happened the plane was usually buffeting around. Not being at the yoke, I couldn't "feel" the controls, and so I cannot offer whether or not this buffet was an indicator of a stall-to-come or not. From previous experience, I did feel uncomfortable in the situation we were in, and after getting out of the plane, I was usually very happy that we didn't encounter any engine problems.

Regarding the pilot's flying, the DZO has been talked to by multiple jumpers. Resolution of the matter, I am not sure of. I'm no longer a jumper.

You'll also notice that I did not bring any specific DZ names on it, and was just adding my input to an above mentioned complaint.

.jim

"Don't touch my fucking Easter eggs, I'll be back monday." ~JTFC

[Hooknswoop 19]

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It's been a while since I hit the pilot training books, but am I missing something?

No, you are spot on, Learningtofly does not understand the purpose of the stall horn, which warns of an impending stall because the wing is nearing the critical angle of attack.

If the pilot needs to clear trees or powerlines at the end of the runway, hanging on the prop with the stall horn blaring will not produce the best angle of climb, Vx.

Derek

[ryoder 1,590]

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Just because you have a parachute and are above 2,000 ft, does not mean you will be able to exit if there is a problem, such as a spin.

Derek

A photographer told me about an incident in which he was in a Caravan that did a stall/spin on jump run. Even though he was only a couple feet from the door, the G-forces had him "welded" to the wall, and he could not move until the pilot recovered from the spin.

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[Hooknswoop 19]

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One that gets me to 2K safely (including still in a straight and level configuration) - after that I have my own nylon 'aircraft'.

2,000 ft or 10,000 feet doesn't mean you will be able to exit. A spin at any altitude can mean you will not be able to exit and if the pilot does not recover, you will die with your nylon 'aircraft' on your back. It has happened before.

Derek

[LearningTOfly 0]

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Let me understand, are you saying that an aircraft is not more likely to stall at a lower airspeed than at a higher airspeed with the same AOA? I have to assume that an engine failure will reduce airspeed. I do not know what the affect on the AOA will be.
educate me please,
James

It's not really a case of 'likely' or not- a stall is not a surprise to a pilot (well, a pilot who pays attention at least). At any airspeed, if say the pilot pulls back on the control, the airflow over the wing will change- that is, the angle of attack (angle at which the relative wind hits the wing) will increase- from 3 degrees to 9 degrees (for example- not exact) in a 2-g pull. If the pilot keeps increasing back pressure (more g's), the AOA will continue to increase- the critical point on most airfoils is somwhere between 14 and 18 degrees AOA. When the airflow hits the wing at such an angle, it produces drag (a burble) that thrust alone cannot overcome, thus a descent results- this descent is prompted by the stall.

Lower airspeeds mean that less g's (less back pressure) need to be pulled to reach the critical AOA on the wing because the wing is already flying at a high angle of attack- Lift is a function of velocity and coefficient of lift (Cl)- if velocity is low, then Cl must be high. The higher Cl's are found at high angles of attack. At approxamately 16 degrees, though, the Cl will spike and drop significantly. This drop is located at the AOA of the stall. (There are charts for airfoils comparing AOA to Cl where this info is taken from) When this drop is encountered, velocity is constant and Cl is reduced, so lift is reduced momentarily. That is, it is less than weight for a moment until the downward vector of velocity increases so now lift equals weight again at this lower Cl.

Added: an engine failure does not affect AOA speifically. An engine failure is a garauntee that you will not maintain altitude, though. If the engine fails and you try to maintain altitude, then you will change the AOA until the wing stalls- after that, your descent will continue.

[LearningTOfly 0]

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It's been a while since I hit the pilot training books, but am I missing something?

No, you are spot on, Learningtofly does not understand the purpose of the stall horn, which warns of an impending stall because the wing is nearing the critical angle of attack.

If the pilot needs to clear trees or powerlines at the end of the runway, hanging on the prop with the stall horn blaring will not produce the best angle of climb, Vx.

Derek

Mr. Buchanan, you are right on in your post.

...

The situation I am thinking of is a short, rough field with obstacles to clear. The aircraft is operating at the edge of it's performance envelope. In a given weather condition: hot temperature and high humidity- the aircraft will need to travel faster to attain the required amount of lift to get off the ground. Reason is that rho (air density) is least, and Lift=0.5*rho*v^2*A*Cl. A higher speed will require a longer time in a state of acceleration, which translated into a longer takeoff roll. Now the trees are getting close fast. What to do- well, the aircraft accelerates more efficiently in the air than on the ground, so 'stalling' it off the ground is a help- flying at 1.05 or 1.1 Vso two feet off the deck, the stall horn is blaring, but you are accelerating the best you can. Still below vx, but not for long. Problem now is that those trees are really close- there's no runway for an abort, and if you loose the engine now, you're sleeping with the squirrels. Two options, start your climb at 1.1 or 1.2 vso and climb out with the stall horn, or build speed to hop over the trees at the last moment. The fact is that vx may not be attainable in cases.

On the other hand, if vx is possible to get over a given obstacle and the pilot dosen't employ such speed, a change should be made to his SOP. Also, vx is not to be maintained, the transition to vy is made asap to help in cooling and general engine health. Climbing the whole ride up with the stall horn going is just plain stupid- the rate of climb is reduced due to drag, the engine is being burnt to pieces due to lack of cooling (if you ever want to piss off a dzo, toast his engine in such a manner- 800 hr tbo, woohoo), and there's no room to deal with gusts/ thermals. Take into consideration, though, that a climb at vy (or between vx and vy) may encounter gusts that cause the stall horn to go off- deal with this- the pilot dosen't want to fall out of the sky any more than you do... okay that was a bad example.

Now if I could only understand the purpose of a stall horn...



Edited to correct spelinng

[tombuch 0]

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The situation I am thinking of is a short, rough field with obstacles to clear. The aircraft is operating at the edge of it's performance envelope. In a given weather condition: hot temperature and high humidity- the aircraft will need to travel faster to attain the required amount of lift to get off the ground. Reason is that rho (air density) is least, and Lift=0.5*rho*v^2*A*Cl. A higher speed will require a longer time in a state of acceleration, which translated into a longer takeoff roll. Now the trees are getting close fast. What to do- well, the aircraft accelerates more efficiently in the air than on the ground, so 'stalling' it off the ground is a help- flying at 1.05 or 1.1 Vso two feet off the deck, the stall horn is blaring, but you are accelerating the best you can. Still below vx, but not for long. Problem now is that those trees are really close- there's no runway for an abort, and if you loose the engine now, you're sleeping with the squirrels. Two options, start your climb at 1.1 or 1.2 vso and climb out with the stall horn, or build speed to hop over the trees at the last moment. The fact is that vx may not be attainable in cases.

There is a third option: abort the takeoff when there is still runway available. A good pilot will know the performance of his aircraft and will not fly when there isn't enough runway. Sometimes that might mean only taking two or three jumpers on a hot day, sometimes it might mean not flying at all.

The situation you describe would drive me directly to another drop zone in a hurry.

A while back I wrote a feature on The Ranch web site about flight safety. It begins with a quick discussion about airplanes, and then deals with pilots. It is Article 14, called "Piston or Turbine Airplanes?" and is available at http://www.ranchskydive.com/safety/index.htm.
.

Tom Buchanan
Instructor Emeritus
Comm Pilot MSEL,G
Author: JUMP! Skydiving Made Fun and Easy

[Hooknswoop 19]

Your reply to; “2. One who doesn't climb the plane with the stall horn going off all the time (What is gained from that).

Hearing the horn scream every time I rode up in the 206 with 4 other fatasses is something I look forward to never doing again...”

Was; “Uh guys, would you like to go up in that 206 on a hot (humid) summer day with five in the back at anything close to a reasonable rate?”

That is not the horn going of for a second as the aircraft lifts off and accelerates.

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The fact is that vx may not be attainable in cases.

And in those cases, the aircraft should not take off.

Derek

[kallend 2,027]

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Your reply to; “2. One who doesn't climb the plane with the stall horn going off all the time (What is gained from that).

Hearing the horn scream every time I rode up in the 206 with 4 other fatasses is something I look forward to never doing again...”

Was; “Uh guys, would you like to go up in that 206 on a hot (humid) summer day with five in the back at anything close to a reasonable rate?”

That is not the horn going of for a second as the aircraft lifts off and accelerates.

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The fact is that vx may not be attainable in cases.

And in those cases, the aircraft should not take off.

Derek

The air temperature above a tarmac runway in the sun on a calm day may be as much as 15 degrees higher than the temperature reported by the airport's "official" measuring site. This can have a huge, unanticipated, negative effect on aircraft performance.

...

The only sure way to survive a canopy collision is not to have one.

[Hooknswoop 19]

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The air temperature above a tarmac runway in the sun on a calm day may be as much as 15 degrees higher than the temperature reported by the airport's "official" measuring site. This can have a huge, unanticipated, negative effect on aircraft performance.

Which would not excuse repeated takeoffs or the stall warning horn going off above 100 ft +/-, except for turbulence.

Derek

[billvon 2,991]

>Now, have you wondered WHY there is a stall horn?

Stall horns on Cessnas are notorious for going off well before stall. During max performance takeoffs at Vx I hear it often, and gusts will often cause it to bleep even at a more normal climb angle.