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-   -   stall warning and when to panic (https://www.pprune.org/private-flying/530865-stall-warning-when-panic.html)

Crash one 30th Dec 2013 20:00

I once stalled a K13 glider at 80knots with about 80deg bank, it took a lot of pull!I've also final turned a C152 at 60deg at 60knots (descending). So all this crap about bank angles wouldn't apply unless you are trying to keep it level without added throttle/speed. Shirley?

Piper.Classique 30th Dec 2013 20:04

Stall warner calibration is a problem with many light aircraft. Fly the attitude please, with a check of the asi from time to time. Learn to feel the aircraft, know how it handles.

And any passenger wanting to take control when I am P1, flying my own aircraft, had better be prepared to learn to fly without arms.

Runaway Gun 30th Dec 2013 20:06

Shirley replies:

This bank angle stuff does apply because as you just pointed out, your stall speed does increase, even if you are in a dive. The majority of pilots are so uncurrent/unconfident in generic 3000ft straight and level stalls, let alone an accelerated version in landing configuration at a high angle of bank at low level. There is a fatal difference.

Shaggy Sheep Driver 30th Dec 2013 20:07


I once stalled a K13 glider at 80knots with about 80deg bank, it took a lot of pull!I've also final turned a C152 at 60deg at 60knots (descending). So all this crap about bank angles wouldn't apply unless you are trying to keep it level without added throttle/speed. Shirley?
Yeah, well obviously! That's because stalling has eff all to do with speed, and everything to do with angle of attack.

I've stalled a Yak at 140 kts, and flown it at zero airspeed with no stall. I do wish all this pish about 'stall speed' would go away! Of course we'd need AoA indicators, and I wonder why they are not standard fit, since flying is all about the wing, and the wing is all about AoA.

My standard dead side descent in the Chippy was done near-wings-vertical, but wings unloaded. Which was also my method of 'throwing away' an aerobatic manouvre where I'd commenced the pull-up and wanted to exit back to level flight quickly and without drama.

Dave Wilson 30th Dec 2013 20:10


And where in your vast experience as a pilot have you developedthe ability to jump in and take control or have learned the necessary skills to make the decision that you are in danger?

Those of us who have been teaching and examining for thousands of hours still have to make margin calls on that one.

Your action of an elbow in the chops while illegally taking command of an aircraft are likely to get you and the commander killed......
Crikey, puff your chest back in! Just a jocular response to your 'rip your arm off' comment, I would be quite happy to die with you Bose.

By the way, just got back from Sainsburys and they have half price Heidsiek champagne on offer if anyone is looking to uncork one the morrow. Just opened a bottle and it's quite quaffable.


I once stalled a K13 glider at 80knots with about 80deg bank, it took a lot of pull!I've also final turned a C152 at 60deg at 60knots (descending). So all this crap about bank angles wouldn't apply unless you are trying to keep it level without added throttle/speed. Shirley?
No, all of this crap about bank angles doesn't apply unless you are in a level turn. Or not loading the wings. Or the various other permutations we've been discussing.


Unauthorised take-over is a breach of Article 142.
So if you were flying with me ( I think you are far more experienced than me if I remember some of your previous posts) and I was P1, the aircraft commander and you were just along for the ride, no matter what I did you wouldn't take over? Even if you called 'Airspeed' if I was low and slow or some other life threatening situation?

Crash one 30th Dec 2013 20:38

No, all of this crap about bank angles doesn't apply unless you are in a level turn. Or not loading the wings. Or the various other permutations we've been discussing.


I thought that's what I said. The glider was certainly loaded, the C152 was not.

Dave Wilson 30th Dec 2013 20:40

Yes you did say that, I was just agreeing!


And any passenger wanting to take control when I am P1, flying my own aircraft, had better be prepared to learn to fly without arms.
Jeez, I give up. On a more serious note, I wonder how many commercial crashes with the loss of many thousands of lives over the years could have been avoided without this attitude. Not having a pop at you in particular but I'm surprised at the more experienced pilots here giving the 'I have a squillion hours therefore how can you ever be more right than me with your 250' line. I thought those days were over.

englishal 30th Dec 2013 21:03


Don't think anyone is disputing that
The number of freshly licensed PPLs who think you can't turn at a bank angle over 15 degrees on base to final is amazing...and a reflection on flight training I am afraid.

Lone_Ranger 30th Dec 2013 21:07

To the OP, I've known stall warners to be conservatively off by up to 10 knots, get the pilot to demonstrate an actual stall at height and compare the airspeed then to airspeed at the warning, he might just know something you don't

He could also of course be an idiot, but at least this way you'll know.

Shaggy Sheep Driver 30th Dec 2013 21:22

Lone Ranger, please read my post above. Stalling is not directly related to airspeed. Because of that, such an IAS indication is meaningless. Wing loading will affect the indicated stall speed, so pilot and pax weight come into it, and fuel weight. And of course if you're in a balanced turn (so G loading becomes a factor) you can forget the IAS / stall relationship.

AoA is ALL the wing knows about as far as stalling is concerned. It never varies for a given configuration (flaps etc), regardless of loading.

ShyTorque 30th Dec 2013 21:24


I am currently "refreshing" ], and the only thing to add to this (apart from the Cessna 152 is 65 knots and you can use 2 stages of flap as there are 3 on the Cessna's), is don't start the final turn below 800ft QFE.
So how do you fly a bad weather/low level circuit?

Lone_Ranger 30th Dec 2013 21:31


Because of that, such an IAS indication is meaningless


Shaggy, read your post./...it does nothing to increase my understanding.
A wing stalls at a certain AoA of course, but it also is most certainly 'related' to airspeed
You seem to be forgetting how a stall warning vane actually works

fireflybob 30th Dec 2013 21:39

Reference passengers interfering with controls, in the event of an accident and injury etc the pilot may be able to take a civil action against the passenger who interfered by proving that such action precipitated the accident.

Shaggy Sheep Driver 30th Dec 2013 21:39


is don't start the final turn below 800ft QFE.
Crikey! Even when I was a PPL stude back in 1978 circuits at Barton were 800' QFE. So by final turn one was down to maybe 500' max (I'd done the rote power, flaps, trim thing on base, and did it again on final).

Once I started to learn to fly into strips etc, height on final turn could be as low as you can go before the wingtip is in danger of hitting the ground!

Now obviously you won't be doing 20 foot final turns as a stude or a low hours PPL... but 800 feet? That's just silly in a little aeroplane (unless there's some local noise rule).


Originally Posted by Lone Ranger
Shaggy, read your post./...it does nothing to increase my understanding.
A wing stalls at a certain AoA of course, but it also is most certainly 'related' to airspeed
You seem to be forgetting how a stall warning vane actually works

There's a relationship between IAS and stall, but it's not in any way reliable for the reason I give (re-read the post). 0 or 140 knots, the stall being at 140! How inconsistent is that? Yes, that was in aeros, so an extreme example.. but it demonstrates the point and the wing has no idea whether it's doing aeros or just circuits.

How do you think a stall warning device works?

No, I haven't forgotten, but your post makes me wonder if you ever knew how it works? If you think it's triggered by IAS, for your own safety go read 'Stick & Rudder' before you become a statistic!

Whether it's a vane or a 'whistle' type of warner, it's triggered by AoA!

fireflybob 30th Dec 2013 21:46

The 800 ft sounds more like a misunderstanding to me.

Quite often a student will say "Instructor Bloggs said this or told me to do this".

And then when you research and ask Instructor Bloggs nothing of the sort was said or something was said which was misunderstood.

This is why as instructors we are in the "communication business" - be precise and make sure what you teach isn't misleading.

fujii 30th Dec 2013 21:47

I'd like to thank all the posters here for pointing out how close to death I have been when flying aircraft without stall warning equipment fitted. What were Geoffrey DeHavilland and others thinking?

Jan Olieslagers 30th Dec 2013 21:49


Fly the attitude please, with a check of the asi from time to time. Learn to feel the aircraft, know how it handles.
Flying a 3-axis microlight with no stall warner installed (cheese us! that would add another 600 grammes or so!) I can only agree. Turned a handful of circuits yesterday, trying various approach speeds and feeling the plane, I am coming to terms with it. Even the one time I let the ASI get rather low I felt it in my pants (or was it my stomach? can't be sure) before confirming on the needle.

Shaggy Sheep Driver 30th Dec 2013 21:52


I'd like to thank all the posters here for pointing out how close to death I have been when flying aircraft without stall warning equipment fitted. What were Geoffrey DeHavilland and others thinking?
Don't you get pre-stall buffet? That was the warning on the Chippy (thank you Mr de Havilland)! And of course it's entirely AoA related (as is every stall warner I've ever met)!

Genghis the Engineer 30th Dec 2013 21:55

Back to the taking control thing.

A real world story of getting it right.

I was right hand seat, instructor, sat back arms folded but monitoring a very good student on his tailwheel (and an antique type) conversion. At 400ft just after take-off, we had a sudden loss of power. My student, not unreasonably said loudly and clearly "you have control Genghis".


I took control, called a Pan, and was manoeuvring to land back (eventually) on a disused crosswind runway. Partway through the manoeuvring - turning, stressed, trying to relate attitude to variably sloping hills around the airfield, and close to the ground, my student recalls noting that I was very close to the stall. His recollection is that he said something like "Genghis, check your airspeed".

I do not recall hearing that. I do recall at that point, glancing at the airspeed, realising from that and stick pressure and pitch attitude that I was close to the stall, and easing the nose forwards. Almost certainly I was responding to what he said, but too stressed to be consciously aware that that was what I was doing.

His clear verbal reminder to me almost certainly saved 2 lives and the aircraft.


I agree that a passenger should not be taking control from a qualified PiC under almost any circumstances. (Obvious circumstances when he might include PiC having a heart attack, or inviting pax to take control to have a go). However, it is excellent airmanship to clearly draw a safety concern to the attention of the pilot. The pilot then, who hopefully knows their aeroplane well enough to form sensible judgments, can do the right thing. In *some* aeroplanes that *might* be to continue to fly with the stall warner operating.

G

fujii 30th Dec 2013 21:57

SSD, I was being sarcastic. People are obsessed with the stall warning and not flying the aircraft.


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