Who here has accidentally stalled a plane?

Mafoo said:
Still not sure I 100% get it. While I get that what your saying is true... if I am doing 100 mph and pull up, I will stall, but won't my indicated airspeed also drop below 60? (if 60 is where I stall)
Click to expand...

Lets look at this from a slightly different perspective that might help. If your pitot tube measures the indicated airspeed, we can consider that effectively your forward velocity through the air. It doesn't tell us anything about the vertical component of your velocity. Imagine that, for some arbitrary paper-exercise-only reason, your plane is flying straight ahead and moving at 90kt through the air. But, it's also falling at a rate of 90kt. Your wing is seeing air move past it at a 45 degree angle coming from ahead and below. You have a 45 degree AoA and the wing is going to stall.

Edit -- heh, Mafoo your last post is exactly what I'm trying to express. I think you're getting it now :)
 
kimberlyanne546 said:
I've heard that before (stall horn during takeoff, in other planes where I was a pax) depending on OAT and WB but I don't THINK I've heard that in my plane since I tend to "let the plane take off" rather than yank / rotate right at rotation speed.
Click to expand...


Man.. you guys /gals flying certified planes are lucky...

Us experimental pilots get to fly without the benefit of stall horn/buzzers/bells.:nonod:;)
 
Mafoo said:
Still not sure I 100% get it. While I get that what your saying is true... if I am doing 100 mph and pull up, I will stall, but won't my indicated airspeed also drop below 60? (if 60 is where I stall)
Click to expand...

No. We're talking about an accelerated stall. Say you plane stalls straight and level at 60 KIAS and a critical AOA of 17 degrees. If you're cruising at 100 KIAS and wrench back you could easily hit your 17 degrees critical AOA but be indicating 100 KIAS. Same true in steep turns. Stall will occur at a higher speed the more Gs you load up.
 
Mafoo said:
I get that it's 100% based on angle of attack, but I thought indicated airspeed was a measurement that gave you feedback as to what your angle of attack was.


So if I am falling 200 mph, and I have the aircraft at such an angle I am indicating 80mph (so I have a high AOA), I am going to be in a stall?

Didn't know that.
Click to expand...

Kimberly posted this earlier today. Enjoy. It is funny but accurate. This guy has a whole training series and all the info is both funny and to the point.

http://www.youtube.com/watch?v=ItMgrp8Cgfg
 
Mafoo said:
I get that it's 100% based on angle of attack, but I thought indicated airspeed was a measurement that gave you feedback as to what your angle of attack was.


So if I am falling 200 mph, and I have the aircraft at such an angle I am indicating 80mph (so I have a high AOA), I am going to be in a stall?

Didn't know that.
Click to expand...


IAS gives you feedback as to AOA. If you are falling at 200mph, you aren't stalled, you just aren't lifting against gravity and your AOA will likely be well within the green.
 
let me ask it a different way....

If my plane stalls at 60 knots, doesn't that mean I need to keep the wind traveling over the wing above 60 knots?

So for example, if I had an aircraft with such a high power to weight ration, I could fly away from the earth at over 60 knots, yet my wings stalled at 60 knots, I could effectively never put myself in a stall at 100% (because I will be making my own angle of attack).

And everyone, I am not saying your wrong. I am just trying to figure out why I am wrong.
 
Mafoo said:
Still not sure I 100% get it. While I get that what your saying is true... if I am doing 100 mph and pull up, I will stall, but won't my indicated airspeed also drop below 60? (if 60 is where I stall)
Click to expand...

No.

Think of the wing....in fact, I might just draw it for you in a moment, but for now:

The wing, in straight and level, has air flowing over it and a constant airspeed. If you pull back, the wing goes up, and the air going over the top and bottom of the wing continues to flow smoothly.

After a certain point, the air starts to get rough around the wing, because the wing is "blocking" the airflow. Picture your hand as the wing, out the window of your car. If you turn your palm so that the air is hitting it at 90 degrees, there's not enough air going over the airfoil to continue lift. This is a stall.

So - regardless of your airspeed, when your wing exceeds that critical angle of attack, it stops flying. Your airspeed could both indicate and true at 100+ knots in an airplane with VS0 of 45, and you'd still be stalled.

We use airspeed because it is an easy reference in straight and level flight. Once you add acceleration, in any plane (up, down, left or right), you don't know what speed you will stall at anymore. But the one thing that remains constant is the wing chord's relative angle of attack to the relative wind. When that exceeds critical angle of attack - you stall.
 
dukeblue219 said:
Lets look at this from a slightly different perspective that might help. If your pitot tube measures the indicated airspeed, we can consider that effectively your forward velocity through the air. It doesn't tell us anything about the vertical component of your velocity. Imagine that, for some arbitrary paper-exercise-only reason, your plane is flying straight ahead and moving at 90kt through the air. But, it's also falling at a rate of 90kt. Your wing is seeing air move past it at a 45 degree angle coming from ahead and below. You have a 45 degree AoA and the wing is going to stall.

Edit -- heh, Mafoo your last post is exactly what I'm trying to express. I think you're getting it now :)
Click to expand...

Thank you. This answers all my questions. I am stupid :p

I get it now :)

Wait... damn... still not 100% sure....

in this senario... wouldn't my indicated airspeed be 45 knots?

If it would be 90 knots, then I see where my mind was disconnecting, and I have it all figured out :)
 
Last edited:
Mafoo. Do a search for accelerated stall. You'll see an article done by Plane & Pilot that will explain everything.
 
Mafoo said:
let me ask it a different way....

If my plane stalls at 60 knots, doesn't that mean I need to keep the wind traveling over the wing above 60 knots?

So for example, if I had an aircraft with such a high power to weight ration, I could fly away from the earth at over 60 knots, yet my wings stalled at 60 knots, I could effectively never put myself in a stall at 100% (because I will be making my own angle of attack).

And everyone, I am not saying your wrong. I am just trying to figure out why I am wrong.
Click to expand...

For reference.....

My experimental is "extremely" overpowered and will go up with the airspeed indicator sitting on 0. I am not really flying, but just being pulling into the air by thrust... If the motor quits during this stunt I am toast.:sad:
 
I had the stall horn chirp once on a short final. My approach angle was low, so I may have been trying to trade altitude for airspeed. However, I noticed the airspeed needle drop suddenly, so there may have been some other external factors contributing (I've never seen it drop that suddenly during actual stalls). I pushed the nose down, and added power to get up to the proper approach angle.
 
Flying_Nun said:
What happens if your pitot-static system becomes clogged while your climbing? I was just discussing this with an "old timer" a couple of days ago.
Click to expand...

Are you asking about pitot tube-only blockages (most likely)?

Your airspeed indicator would show faster airspeeds as you climb and slower airspeeds as you descend (think of your airspeed indicator as acting as an altimeter in the event of a pitot tube blockage).
 
MAKG1 said:
Even worse, he insisted in taking off directly into the very light wind. The cross-runway would have kept him completely clear and legal, and well away from the stall.

I don't know why everyone at WVI insists on using 20 all the time. It's the designated calm wind runway, but safety always trumps noise abatement. For the fairly common case where the south end of the field is fogged and the rest isn't, 20 is the wrong choice. Even if the wind is blowing 20 knots straight down 20.

I don't know if that crash was officially labeled a stall/spin, but it sure as heck looked like it.

FWIW, the building at Watsonville Community Hospital he destroyed was vacant. The only people he killed were himself and his family.

That accident occurred right around my first solo. It did not make the wife comfy.
Click to expand...

On that note we had an 'air boss' temporary tower at our field last week for a big fly in / airshow that had guys landing with a solid 10+ kt tailwind. That included a few taildraggers.. lucky there were no groudloops.

Stalling has to do with angle of attack and not airspeed. Lets say my airplane stalls at 45kts but I can easily stall it at 60 if I want to. That is an accelerated stall.
 
Mafoo said:
Wouldn't the best senario be to know best rate of climb for a fully loaded aircraft at whatever altitude you are, and then just fly that speed. If you look like you are not going to clear what's in front of you, you need to fly somewhere else, because nothing you do is going to fix that?
Click to expand...

Yes, but sometimes the situation doesn't cooperate.

For instance, there are airports (Big Bear being an example) where terrain rises in all directions. Fortunately, it's far away to the west, so if you can climb at all, that's a way to deal with it.

Sometimes the wind causes downdrafts. That's common downwind from mountains. And wind is a common reason to take off toward rising terrain.

Probably the most common errors in situations like this are (1) no, insufficient, or incorrect preflight planning, perhaps combined with overloading, or (2) using sea level procedures at high altitude. At high altitude, full rich is never correct, and Vy is slower than you might expect. You also need a lot more runway than you would at sea level.

The trick is to leave a lot of margin for everything. And always have at least one backup plan for when things don't work as you expect. Don't be afraid to call a no-go if there isn't any such backup (in the mountains, you'll often do much better early in the morning than in the afternoon).
 
jasc15 said:
I had the stall horn chirp once on a short final. My approach angle was low, so I may have been trying to trade altitude for airspeed. However, I noticed the airspeed needle drop suddenly, so there may have been some other external factors contributing (I've never seen it drop that suddenly during actual stalls). I pushed the nose down, and added power to get up to the proper approach angle.
Click to expand...

You probably had a little shear on the way down.

Its normal to have the stall horn chipring and probably momentary stalls of the aircraft while climbing out at Vx on a turbulent day.
 
CBeaulieu said:
Are you asking about pitot tube-only blockages (most likely)?

Your airspeed indicator would show faster airspeeds as you climb and slower airspeeds as you descend (think of your airspeed indicator as acting as an altimeter in the event of a pitot tube blockage).
Click to expand...

Huh ?????

When the pitot tube gets blocked you have 0 airspeed showing...
I think you meant static blockage..:dunno:
 
Just want to ask this question again, because I think it's the missing piece.

If you are traveling though the air level at 90 knots, and you are also dropping out of the sky at 90 knots, (so the air is hitting your pitot tube at a 45 degree angle), what would your indicated airspeed be?
 
Mafoo said:
let me ask it a different way....

If my plane stalls at 60 knots, doesn't that mean I need to keep the wind traveling over the wing above 60 knots?

So for example, if I had an aircraft with such a high power to weight ration, I could fly away from the earth at over 60 knots, yet my wings stalled at 60 knots, I could effectively never put myself in a stall at 100% (because I will be making my own angle of attack).

And everyone, I am not saying your wrong. I am just trying to figure out why I am wrong.
Click to expand...

Because though the IAS determined through air rammed into the fixed angle pitot can be an indicator, it is a **** poor one with it's ratio of **** poorness increasing exponentially as the AOA increases :goofy:

(Actually it's probably not exponential - I don't know.)

The IAS at which your POH lists stall assumes 1g. Increase the g's such as by increasing your bank angles, your POH should indicated a highter stalling indicated IAS.

Here's a very simple one from my old CAR 3 -certified airplane manual which demonstrates, attached.

Relying on one IAS ("60 knots" or whatever) to give you a benchmark for stalls in 1g conditions during different density altitude situations which could change your flight characteristics, is good. At different manuevers which result in pulling more than 1g, not so good.

By the way, also on that page is something mildly controversial that might interest Cessna fans :yesnod:
 

Attachments

  • 56_Owners_Manual[1] 36.pdf
    41 KB · Views: 12
Last edited:
Mafoo said:
Just want to ask this question again, because I think it's the missing piece.

If you are traveling though the air level at 90 knots, and you are also dropping out of the sky at 90 knots, (so the air is hitting your pitot tube at a 45 degree angle), what would your indicated airspeed be?
Click to expand...

Look real close at the dial on the ASI... Just below zero is the small letters.. NTSB.;):eek::lol:
 
On the way to my first Oshkosh. Was following someone flying a lot slower than 90 knots. One second I was trying to keep behind him, the next I was looking at the ground. Recovered quickly and got back in line.
 
Mafoo said:
Just want to ask this question again, because I think it's the missing piece.

If you are traveling though the air level at 90 knots, and you are also dropping out of the sky at 90 knots, (so the air is hitting your pitot tube at a 45 degree angle), what would your indicated airspeed be?
Click to expand...

Who knows. Every aircraft will indicate significantly less. It just depends on the airframe. Just like in your C-150 55 KIAS will be pretty close to your calibrated speed. In my Glasair 55 KIAS produces a significant nose up so my calibrated is around 60. If it were standard conditions then that calibrated would also be my true.
 
N801BH said:
Huh ?????

When the pitot tube gets blocked you have 0 airspeed showing...
I think you meant static blockage..:dunno:
Click to expand...

The pressure in the clogged pitot tube would remain constant while the atmospheric pressure would increase/decrease as the aircraft ascends/descends.
 
Last edited:
Mafoo said:
Just want to ask this question again, because I think it's the missing piece.

If you are traveling though the air level at 90 knots, and you are also dropping out of the sky at 90 knots, (so the air is hitting your pitot tube at a 45 degree angle), what would your indicated airspeed be?
Click to expand...
Theoretically it would only indicate the component parallel to the pitot tube, which is 90 knots. Your actual airspeed would be 127 knots, at a 45 degree angle of attack. Since the difference between KIAS and KCAS varies with AOA, who knows what it would actually indicate.
 
N801BH said:
Huh ?????

When the pitot tube gets blocked you have 0 airspeed showing...
I think you meant static blockage..:dunno:
Click to expand...

Most airspeed indicators use pressure differentiation between air rammed into the pitot system and pressure present in the static system to indicate airspeed.

If a pitot is completely blocked the pressure present inside the pitot is equal to the pressure in the static system. That won't result in a zero reading, it will result in some arbitrary number which will change with the altitude. you've just turned your AI into a lousy, uncalibrated altimeter.

Your plane might have a little wind vane in your pitot tube, maybe, but most don't :rofl:
 
Last edited:
jasc15 said:
Theoretically it would only indicate the component parallel to the pitot tube, which is 90 knots. Your actual airspeed would be 127 knots, at a 45 degree angle of attack. Since the difference between KIAS and KCAS varies with AOA, who knows what it would actually indicate.
Click to expand...

ok, I get it now...

Thanks everyone. This was a very educational thread. Thanks for all the input :)
 
alaskaflyer said:
Most airspeed indicators use pressure differentiation between air rammed into the pitot system and pressure present in the static system to indicate airspeed.

If a pitot is completely blocked the pressure present inside the pitot is equal to the pressure in the static system. That won't result in a zero reading, it will result in some arbitrary number which will change with the altitude. you've just turned your AI into a lousy, uncalibrated altimeter.

Your plane might have a little wind vane in your pitot tube, maybe, but most don't :rofl:
Click to expand...


Interesting.... I thought the ASI needle was moved by air pressure against a bellows, supplied by the pitot tube in a sealed circuit and the case was connected to the static source to correct any imbalance.
 
N801BH said:
Interesting.... I thought the ASI needle was moved by air pressure against a bellows, supplied by the pitot tube in a sealed circuit and the case was connected to the static source to correct any imbalance.
Click to expand...

It is, but if you block the tube, you trap that pressure.
 
N801BH said:
Interesting.... I thought the ASI needle was moved by air pressure against a bellows, supplied by the pitot tube in a sealed circuit and the case was connected to the static source to correct any imbalance.
Click to expand...

I should have been more specific and said "total blockage" in my first post. I have a hard time explaining things in text sometimes...:dunno:
 
Like Tony a couple of pages ago, many times.
I'm assuming Tony's commenting on glider flying. When you're yanking and banking and trying hard to core a turbulent thermal, it happens. It's a good demonstration both of the exponentially higher stall speeds in steeper banks and the AoA excursions that turbulence can cause.

Yet another reason that flying gliders can improve one's stick and rudder skills.
 
This is what I was taught. Has anything changed?

Blocked pitot tube
A blocked pitot tube is a pitot-static problem that will only affect airspeed indicators.[6] A blocked pitot tube will cause the airspeed indicator to register an increase in airspeed when the aircraft climbs, even though actual airspeed is constant. This is caused by the pressure in the pitot system remaining constant when the atmospheric pressure (and static pressure) are decreasing. In reverse, the airspeed indicator will show a decrease in airspeed when the aircraft descends. The pitot tube is susceptible to becoming clogged by ice, water, insects or some other obstruction.[6]
 
Pet peeve here.

"Exponential" means something very specific. It means the stall speed doubles every so-many-degrees. It doesn't behave that way at all.

Vs' = Vs / cos(bank)

It's not that hard, and it's NOT exponential. That assumes coordinated, level flight. If you add in accelerations, all bets are off.
 
I got the horn and buffet at low altitude when the flap handle skipped a couple notches during incremental retraction during climb-out while executing a rejected landing (balk.) The problem was traced to a glitch in the mechanical linkage due to the spring-loaded button on the end of the flap handle coming partially unscrewed over time. Instead of holding at the desired setting, the flap handle moved unexpectedly to 0 (handle flat on the floor.) It was evidently one of those things that can't happen but did, and the "flap handle button screwed in tight" is now part of pre-flight checks.

Horn and buffet will not always activate/occur during uncoordinated flight. Some stall-spin accidents are thought to occur due to the surprise element when no warning is provided. Even though spin training is no longer required, stalls and spin entries are legitimate training exercises. I encourage pilots to practice various scenarios at altitude with an instructor in order to become accustomed to the "what the . . . " disorientation that can accompany a wing tucking under or flipping over the top.
 
Velocity173 said:
This is what I was taught. Has anything changed?

Blocked pitot tube
A blocked pitot tube is a pitot-static problem that will only affect airspeed indicators.[6] A blocked pitot tube will cause the airspeed indicator to register an increase in airspeed when the aircraft climbs, even though actual airspeed is constant. This is caused by the pressure in the pitot system remaining constant when the atmospheric pressure (and static pressure) are decreasing. In reverse, the airspeed indicator will show a decrease in airspeed when the aircraft descends. The pitot tube is susceptible to becoming clogged by ice, water, insects or some other obstruction.[6]
Click to expand...

that is how I have always understood it.
 
MAKG1 said:
Pet peeve here.

"Exponential" means something very specific. It means the stall speed doubles every so-many-degrees. It doesn't behave that way at all.

Vs' = Vs / cos(bank)

It's not that hard, and it's NOT exponential. That assumes coordinated, level flight. If you add in accelerations, all bets are off.
Click to expand...
Your pet peeve is legitimate, and I accept I was not correct in the use the word exponential. However, if we want to be correct, exponential does not mean something doubles every so and so. It means it increases by some power or exponent every so and so. That exponent can be many things besides 2. And to be further precise and specific banked flight is accelerated flight.
 
Velocity173 said:
This is what I was taught. Has anything changed?

Blocked pitot tube
A blocked pitot tube is a pitot-static problem that will only affect airspeed indicators.[6] A blocked pitot tube will cause the airspeed indicator to register an increase in airspeed when the aircraft climbs, even though actual airspeed is constant. This is caused by the pressure in the pitot system remaining constant when the atmospheric pressure (and static pressure) are decreasing. In reverse, the airspeed indicator will show a decrease in airspeed when the aircraft descends. The pitot tube is susceptible to becoming clogged by ice, water, insects or some other obstruction.[6]
Click to expand...

Here is why I said what I said....

Bugs will block a pitot completely, that usually happens down low, like 500agl or lower. Most pilots will land to fix the problem and not fixate on the ASI changing 1-2 kts...

Up high, icing will block the pitot, but it happens gradually and during the time it gets obstructed the airspeed decays to a very low number, then it seals over... The chances of a total obstruction in an instant, out side of pattern altitudes, is VERY low. IMHO.

What are the symptoms of a icing over pitot ?
 
Mafoo - I hate to say this but unless you are in "lessons learned" where people can post anon - I doubt you will get many to confess to making mistakes on a public forum. I have seen pilots do this before (and I've done it).... but then when even one reply rips the pilot a new one so to speak they end up keeping their mouth shut going forward.

If you want to ask and get honest answers, try going to local pilot meetings or taking the question offline and in person or via PMs.

Not many pilots who have made mistakes brag about them.... but most, in person anyway, when they see why you are asking the question.... will give you the answers you seek.
 
You must log in or register to reply here.
Back
Top