Minimum height for practice stall recovery in C172

[Tee Emm]

Question: Traditionally most flying schools mandate that the minimum height above terrain by which to recover to level flight for stall recovery practice is 3000 feet - meaning the pilot must be above that height on commencement of the practice.

There appears to be no CASA regulation nominating that restriction. What is the rationalisation for that stall limitation? From where did that "tradition" start and is it a valid requirement considering the POH for the Cessna 172 states "Altitude loss during stall recovery may be as much as 230 feet"

This would suggest a recovery policy by 3000 ft is grossly exaggerated and not cost efficient to the student. Stall recoveries are not aerobatics where there is a 3000 ft min height restriction.

[Old Akro]

I wouldn't like to face the legal argument that a stall is not an aerobatic manoeuvre. It is a manoeuvre where you don't have full control over the aircraft. There is no clear definition of aerobatic flight (ask John Quadrio who lost is licence over a technical point about aerobatics that CASA won in the AAT). However, the FAA definition is widely accepted:

Any manoeuvre involving an abrubt change in an aircraft’s attitude, an abnormal attitude, or abnormal acceleration, not necessary for normal flight

If something went wrong and were were doing stalls under 3,000 ft I think you'd find yourself in a whole world of pain with CASA.

Remember that the Cessna height loss figure comes from a perfect aircraft. Add in some mis-rigging developing over the years, a cofg at the back of the envelope, wrong initial control inputs from a student and the answer will be completely different.

And I have a mate who is dead after giving a potential purchaser a test flight who stalled the aircraft then messed up the recovery without sufficient height for my mate to recover it.

You know the saying about useless things in aviation....

[ForkTailedDrKiller]

I have always understood it to be "recovered by 3000'" - although I would have to admit to doing stalls much lower than that, with a highly experienced instructor. :E

Dr :8

[ButFli]

It was explained to me during that part of my training that although stalls were not considered aerobatics, in the absence of a set rule it made sense to follow the requirements for aerobatics just to be safe (recovery by 3000' being one of them).

I'm not sure how much a student would save by doing stalls below 3000. Not much compared to the price of a new aircraft after you have a prang in this one, I'm guessing. Out of all the things you could complain about the cost of flight training this would have to be low on the list.

Although... Maybe it's a big conspiracy by the flight school to get an extra $10 out of students? :rolleyes:

[Ultralights]

Wing at 16 deg AOA, stalled, wing at 15 deg AOA, unstalled. Height loss about 10ft at most, as you move the stick fwd a fraction to effect the 1 deg pitch change. :ok:

Now going from 16 deg AOA stalled to 0 deg AOA nose at 20 deg negative pitch dive while pushing full power, then you will lose far to much height than actually needed to recover.. :ugh:


What method is taught the most and why?

And which method of stall recovery would you prefer if you stall on mid or short final? (Yes, final, not finals, you can only fly 1 final at a time)
bury the nose into the ground recovering, or just releasing enough back pressure to get the wing from 16 to about 15 or 14 deg AOA, where it will still fly happily, unstalled. Even in a turn....:ok: assuming you know how to use a rudder and the ball is centered.

[VH-XXX]

As I understand it there is no legal requirement to begin or end your stall at 3,000ft however it has long been considered best practice in training circles.

As I understand it you would be free to stall an aircraft at 1,000ft.

[Nomde plume]

It's the school's plane and the school's instructor, if they say recover by 3000' (which by the way is usually written in the ops manual so I suggest you check it), then end of story, that's it.
Your own plane, the safety of the flight is your responsibility, and if there is no regulations regarding it, it's your call.
Keep in mind that an inadvertent spin can take 1000'+ to recover!

[Old Akro]

Those who don't think stalls are an aerobatic manoeuvre should read the thread on John Quadrio. He was hung out to dry by CASA for a more benign manoeuvre on the basis of a passengers video.

Also remember that schools teach 1g level flight stalls. As a previous poster correctly identified you can achieve 15 deg AOA at nearly any speed in nearly any attitude

[ForkTailedDrKiller]

And which method of stall recovery would you prefer if you stall on mid or short final? (Yes, final, not finals, you can only fly 1 final at a time) bury the nose into the ground recovering, or just releasing enough back pressure to get the wing from 16 to about 15 or 14 deg AOA, where it will still fly happily, unstalled. Even in a turn....http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/thumbs.gif assuming you know how to use a rudder and the ball is centered. ??????????

Have you ever stalled a C150, PA38..............or even a BE35 with 20o flaps and 1800 rpm ?

I used to instruct in a PA38 that would promptly roll onto its back every time!

Dr :E

[43Inches]

Do not forget that the aircraft is not the only threat during stall practice. I know of at least three instructors who have had a student lock up on the controls with full back pressure during stall practice and lost 1000-2000 feet during the recovery. One of these was in a PA28 which suprised the student with a wing drop in a straight and level power off stall.

Whilst a straight and level stall may not constitute an aerobatic manuevre it can very quickly turn into one without much warning when inexperienced pilots are involved.

[chimbu warrior]

Hmmmmm, I regularly stall aircraft at zot feet. It's how we land.......

[43Inches]

Hmmmmm, I regularly stall aircraft at zot feet. It's how we land.......

Many aircraft I've flown you'd be scraping the tail off trying to stall it onto the ground.

[Avgas172]

So what's the suggestion .... I clearly recall an inverted spin in a PA38 with a 1500ft recovery, with a highly experienced (22 hour) student. I live today as a result of having 4000 ft to play with on the way down .... happy to pay the extra 3 minutes of climb time for that myself ... :ugh:

[5-in-50]

The C172 G1000 POH states that slow deceleration stalls are not considered aerobatic (excluding whip stalls). Refer section 2 of POH.

The recovery by 3000ft is an arbitary figure that is unneccessarily linked to aerobatics practice and carried through by generations of Instructors.

I've seen Ops manuals that approve straight and level stall practice below 3000ft with CFI approval.

I'm not aware of any CASA height rule regarding straight and level stalls, only aeros.

[josephfeatherweight]

happy to pay the extra 3 minutes of climb time for that myself
I love it! Wise...

[Capt Fathom]

Avgas172
an inverted spin
So you stalled the aeroplane inverted..... With forward stick and rudder applied?

[DH164]

A large bunch of precious pansies in this thread.

[Old Akro]

The C172 G1000 POH states that slow deceleration stalls are not considered aerobatic

I'm more worried about what CASA thinks. Read the John Quadrio thread.

Height itself is not necessarily an issue. I used to do flick rolls below 1000 ft in competition. Its all about the context.

[Deaf]

What is the rationalisation for that stall limitation? From where did that "tradition" start and is it a valid requirement considering the POH for the Cessna 172 states "Altitude loss during stall recovery may be as much as 230 feet"

Like a lot of this stuff "written in blood". Allowing for 3,000 AGL by recovery is OK in a 172, in tricker a/c it is gone by 3,000 or 10,000 assuming you have made sure you have the option.

Have lost 500 in a deliberate stall in a J160 in go round mode (full flap full power). Stall was deliberate spin was not. I do have the upright spin bit in the logbook so not so bad when you start at 3,500. No more stalls till I have had an session in a 152 Aerobat with instructor with me in the RHS (L Hand on throttle R hand on stick-wheel).

Now think of student recognizing the problem and trying to remember theory or even the G3 200 hr instructor also headed down - needs time = feet.

[fujii]

(2) For the purposes of subregulation (1), straight and steady stalls or turns in which the angle of bank does not exceed 60 degrees shall be deemed not to be acrobatic flight.
(3) A person must not engage in acrobatic flight in an aircraft:
(a) at a height lower than 3,000 feet above the highest point of the terrain, or any obstacle thereon, within a radius of 600 metres of a line extending vertically below the aircraft; or
(b) over a city, town, populous area, regatta, race meeting or meeting for public games or sports.

Therefore there is no height requirement for stalling except for the requirements in CAR 157.

[dubbleyew eight]

a bit of unexpected turbulence in the middle of the stall and you'll wish you were at 10,000 ft.

[LadyLlamapilot]

Have any of you jokers done a Low Level Endorsement?
I recall doing stall practice at 150ft during mine. After all, when we fly at work we are no higher, and sometimes lower than that, so we need to be able to deal with it. It is amazing how stalling so close to the ground hones your desire to conduct the perfect stall recovery!!!

[djpil]

fujii, that is only for the purposes of subregulation 1 which, from memory ...
should've read the reg rather than rely on memory, sorry.

[ForkTailedDrKiller]

Excuse My Limited Aerobatic Experience
Avgas172
Quote:
an inverted spin
So you stalled the aeroplane inverted..... With forward stick and rudder applied?

Methinks Avgas is confusing an inverted spin (I suspect nigh impossible in a PA28 without very deliberate control inputs and maybe a somewhat rear CofG) with an upright spin that started out with the aeroplane rolling over initially before getting itself sorted out in a conventional spin (far more likely). :E

But Captain, I am far too polite to say so. :)

I pondered this muchly when teaching myself aeros in a C150 Aerobat. Even read Neil Williams book cover to cover :confused: - before I figured out that you would have to work really hard to get an Aerobat in an inverted spin, if even possible, and even harder to keep it there.

I did, however, teach myself snap rolls - with the aeroplane in one hand and the POH in the other. The first one went really well :E - I only lost 1000' before I recovered from the inevitable spin and was left wondering what the hell just happened!! Fortunately I started my "lesson" at 9000'.

Dr :8

[LeadSled]

Folks,
Read what OldAkro says, then read it again, then read what OldAkro says.

Most of us who have been around the instructing business for a while have had "something interesting" happen.

If a DC-3/C-47 drops a wing in a stalling sequence, it will roll into a spin, recovery can take 5000'.

A Cessna 172 with some flap out and an aft C.of G doesn't need too much mishandling to roll on its back. I have personally had that happen twice, as I have always insisted, during a checkout (or in the days when endorsements were required, an endorsement) that the candidate fly the stalling sequences ( and please don't tell me "they are not required", if I am signing off a pilot, it will only be when I think he or she is competent) in a representative configuration ---- which is, in a C-172, for my money, loaded close to max. weight and close to the aft C.of G ---- ie: with the equivalent of four aboard and a few bags in the back, the equivalent of taking mum and the kids away for the weekend.

In a recently describe incident with a flying school a C-152 got into a flat spin, it took more than 2000' for the very experienced instructor to recover. Interestingly, nothing was found wrong with the rigging, the "why" was never established, but of the "what happened", there is no doubt.

TraumaHawks are famous for doing all sorts of unpredictable things.

Any of us who have flown what are now some wonderful old "vintage" aircraft, but were the flying school fleet of their day, didn't practice stalls, we practiced stalls and spin recovery. Anybody remember the taper wing DH Hornet Moth.

As for suggesting in a (very sniffy ) tone that stalls are required at low level for a low level rating, that is silly to suicidal, depending on the aircraft type --- or, in technical terms, very poor risk management --- please show me the CASA requirement for stall and recovery at 150', and I will show you another case of CASA gross incompetence.

Tootle pip!!

[dubbleyew eight]

nothing to do with us but two guys died off the end of our strip.
stalled a T18 with full flap.

I think no c of g problem.
aircraft had the original T18 wing with mediocre stall characteristics.
aircraft flipped on its back.
recovered upright but with both wings stalled.
ballistic fall to earth.

stall anywhere you like. we need fatal accident statistics to convince people that flying is dangerous. you too can help:E:E:E

[Oktas8]

Stalling cannot be an aerobatic manoeuvre: let's put that myth to bed. Here are three reasons for it, although there are others.

Manufacturers: Many aircraft have something like "spinning and other aerobatic manoeuvres are prohibited" written as a limitation in the AFM or POH. But all aircraft can be stalled for training purposes, at an appropriate height.

CASA: Aerobatics cannot be conducted as PIC without being endorsed to perform upright spins. Yet pilots of all experience levels go out to practise stalling, without being endorsed for spinning.

Pilots: It's useful for type ratings (endorsements, whatever) to conduct stall recoveries at close to MTOW and an aft CG. None of us would conduct aerobatics under those circumstances in normal-category C of A aircraft, and the manufacturer would prohibit it anyway. Yet intentionally stalling in that configuration is fine, with an instructor.

"Unaccelerated stalls are not considered to be aerobatic manoeuvres, by manufacturers, by CASA, by pilots." Say that three times before bed, daily!

Not that I've any objection to the 3000' principle in modern aircraft for basic training. Let's just not confuse it with a Rule or a Limitation.

[43Inches]

The original question asked why flying schools directed stall practice to be conducted at a height to be recovered by 3000ft agl. It also asked whether this was a waste of a students money. Many posts here are debating whether a stall is an aerobatic manuevre and stalls can be conducted during low level aerobatics at 150ft. This is completely irrelevant to the initial question, once it's in an ops manual it is a rule.

If you believe nothing can go wrong with a level un-accellerated stall during basic training then you have not spent enough time instructing. There are many cases of stall training/practice going wrong and even from higher altitudes not being able to recover. This is the reason for the height stipulation. It's easy for a flying school to impose the same limits for aerobatics as for stalling as history has shown that these training sessions can turn into aerobatics very quickly.

There is a big difference between an experienced aerobatic pilot conducting precision manuevres and a student who can barely coordinate their arms and legs. Even the experienced aerobatic pilots get caught out and end up in the dirt all too often.

Here is an example of what a student can do;
During stall practice aircraft entered a slight wing drop to the left, student reacted with full right rudder initiating a spin to the right. This suprised the student so he locked up on the controls with full back-pressure and full right rudder, left aileron to try and stop it rolling. Next thing the instructor had to overpower the student from the controls and recover, this required around 2000ft. The instructor even had his foot in a position to stop over reaction but the students input was such that he overpowered the instructor initially.

[Oktas8]

3000' has historically been used as a minimum recovery height for abnormal flight, in many countries. I think it originated in pre-WW2 military flying training. As others have said above, in aircraft of an earlier era, 3000' really was barely enough to be safe - when aircraft would spin without hesitation for example. Nowadays I can think of some aircraft which also require more than 3000' to safely practise stalling.

Is 3000' excessive today? In some cases, yes. (I'm thinking of an aircraft which is highly spin resistant, a pilot with enough training to have ironed out basic errors, and a real need to be lower - not just "because I can"!) But in my experience, the pilots pushing for a lower height are the ones who should stay high, for human factors reasons. If you follow my meaning. ;)

Anyway, a competent instructor will usually not have to waste time & money to get to 3000'. There are things to do on the way up and on the way down again.

[43Inches]

Anyway, a competent instructor will usually not have to waste time & money to get to 3000'. There are things to do on the way up and on the way down again.

In addition to that what is the point of just doing S&L stalls in a stalling lesson. Once the student has a handle on the principles some climbing, descending and turning stalls should be done to finish off. In a 172 you should be able to do a lot in 1 hour of stalling, 2 on board without excessive fuel should take very little time to climb to 3000+. I remember a student once going on 2nd training area solo climbing to 8500ft in a 152, he then tried a PFL, imagining he was over tiger country and gliding into a clearing. He also did some steep turns and general practice all done within 1 hour vdo.

[Old Akro]

My point is still that CASA won't necessarily be rational or reasonable. Whatever definition you find of aerobatic, another conflicting one can be found. Its a very, very grey area. If CASA apply the same definition of aerobatic they did for John Quadrio and accept similar sketchy evidence, then the instructor will be looking for a new career.

Disgruntled resident filming from below and labelling it as dangerously low, or proud student posting a video clip on Youtube and we've got a party starting.

Read the Quadrio thread. CASA cannot be trusted to be reasonable. I'd regard climbing to 3,000 ft as cheap insurance.

[rutan around]

3,000 ft is indeed cheap insurance. In a clean aircraft 4,500 ft is even better. After thousands of hours in a C210 I didn't think it held many surprises. Everyone has the occasional 'off ' day and I had one of those a couple of biennials ago. We were doing numerous power off stalls and the instructor was encouraging me to recover with less altitude loss each time. Must have had a bit of a fuel imbalance because each time the starboard wing dropped as it stalled and I was starting to apply left rudder the moment it stalled. We had been applying power as the nose fell below the horizon. On the last stall trying to achieve a really small height loss I got over enthusiastic. At the first indication of the stall I applied full left rudder and then unfortunately went to full noise too early while the aircraft was still partially stalled. What happened next took me completely by surprise.The aircraft flicked very suddenly to the left and found myself in a spiral dive looking straight down with the sea view 4,500feet below filling my windscreen. I've never felt acceleration like it. At 32 ft/second/second assisted by 300HP and a clean airframe left unattended we were about 10 seconds from the water. That's a lifetime for experienced aerobatic pilots but I'm not and I felt more disorientated than the last diehards to leave the Cairns ATC Xmas bash.

With calm words from the instructor ( an aerobatic pilot) all was sorted except my jocks.

The point I'm trying to make is that even docile types like C210s can bite if flown into unusual situations by hamfisted pilots and the more time you have before the earth riseth up to smite thee the better.

[dubbleyew eight]

in the T18 incident I mentioned one of the guys was a very highly regarded and very experienced instructor. they stalled at about a thousand feet during familiarisation training.

in the fatal prang at Sale the pilot was a qualified test pilot. it was just a low level stall.

in the prang at Aldinga the passenger had 29,000 hours. it was just a low level stall.

all 3 of those fatal accidents were the result of a simple stall occurring and none of the guys involved were novices.

you get complacent at your dire peril.

[Oktas8]

We were doing numerous power off stalls and the instructor was encouraging me to recover with less altitude loss each time.

Now I wasn't there, so I cannot criticise this particular situation. Anyway you learned something, which is good!

But... There is very rarely any point in doing stalling over and over with this aim. In fact I can think of only two: low level endorsement work, and remedial for a student being lazy with attitude control.

No one crashes an aeroplane because they lost 50' instead of 20' in a stall recovery. People sadly do crash because they rush, and botch, a recovery.

I once accidentally stalled an aircraft at 250' in a full power steep turn.* How much height did I lose? Less than 250'. Saying anything else, I believe, misses the point of a stall recovery.


* Yes it was legal. Yes it was careless. No it hasn't happened since. :}

[A37575]

Many years ago I cadged a ride in a two place glider at BCS. After tow release around 1500 ft the instructor demonstrated stall recovery. He did the same thing while on the downwind leg also at 1500 agl. I then had a go and recovered within 50 feet and of course no engine.
I don't know about now, but in those days stalling in gliders at relatively low altitude was normal teaching

If flying schools will only teach stalling above 3000 ft then how come there is no problems with gliders which don't have props to aid stall recovery.

[desert goat]

Most gliders I've flown have fairly benign stalls and good low speed handling, as they are designed to spend most of their day in a steep bank close to the stall. You are also likely to lose a lot less height in each turn of an inadvertent spin than you would if you were in Rutan Around's C210, and without the variables of the power and flaps to consider, that inadvertent spin is less likely to occur in the first place. It's not really a comparable situation.

[Old Akro]

props to aid stall recovery.

Why do you think props aid stall recovery?

[dubbleyew eight]

Why do you think props aid stall recovery?

because they do. if you catch a stall, just as it is occurring, with a goodly burst of thrust from a propeller you will pull forward out of the stall.

...with just about no loss in height. it is a matter of timing.

[Ultralights]

im concerned about the number of aircraft that will enter a spin without a rapid Yawing component at the point of stall. :sad:

and how does a burst of power pull you out of a stall? how does it lower the wings AOA? :(

[Tankengine]

A propeller on the front can in fact help cause an upset due to one wing stalling more than the other.:ugh:

[Old Akro]

because they do. if you catch a stall, just as it is occurring, with a goodly burst of thrust from a propeller you will pull forward out of the stall.

Or take it deeper into the stall.

Stall is about Angle of Attack, not speed. You can be a 10 knots (top of a loop) and not be stalled or 150 kts and be stalled (flick roll).

[ForkTailedDrKiller]

a goodly burst of thrust from a propeller you will pull forward out of the stall

Now there is a new concept in the theory of aerodynamics! :confused:

Dr :8

[Tankengine]

Yep, FTDK and Old Acro,:ok:
It really shows how easy basic flying is!:E
Some of the crap written here makes you wonder how some guys get from A to B without "plummeting" to Earth!:rolleyes:

[Ultralights]

xwrfEsCiltc

[27/09]

if you catch a stall, just as it is occurring, with a goodly burst of thrust from a propeller you will pull forward out of the stall.

You might.........then again .................you might not, as mentioned already, stalling is all about A of A not airspeed.

This "Goodly Burst of Power" you speak of will more than likely result in a wing drop stall.

The increased A of A on one wing due to the increased prop wash on it's own could cause a wingdrop, and if that doesn't induce a wing drop, the yaw from the increased slip stream probably will, as most pilots won't add sufficient rudder input to stop the yaw.

[Nomde plume]

I've seen a fairly benign stall turn in to a spin because a student applies power while holding the stick back on the stops. Most aeroplanes have a pitch up tendency associated with applying power, amplified by low airspeed and flaps, this can create a much deeper stall than a power off clean stall.

Anyone who says a stall recovery can be achieved with zero height loss has little appreciation for flight on the arse end of the drag curve!

[bentleg]

Quote:
if you catch a stall, just as it is occurring, with a goodly burst of thrust from a propeller you will pull forward out of the stall.







Only if you push the stick forward first to fix the angle of attack......

[john_tullamarine]

because they do. if you catch a stall, just as it is occurring, with a goodly burst of thrust from a propeller you will pull forward out of the stall.

An interesting and novel thought ..

Before you kill yourself one of these days .. you might like to read up on certification requirements .. CAM 3, FAA Order 8110-7 (if you can find a copy - if you do, please let me know what URL you visited to achieve that) or AC 23-8/8A/8B/8C should cover most of the aeroplanes you are likely to fly ...

As an alternative to killing yourself (although that may still occur sequentially) you might pick up some experience of spins - erect or inverted as the particular aeroplane prefers to exhibit.

For aeroplanes with larger engines, as Nomde plume observes, the normal prop force can give you a distinct lack of control over a rearing beast ... some aircraft require SAS to address this problem for the missed approach.

Prior to the stall .. the power trick might be useful .. it was great fun powering out on the Electra at light weights ...

And so it goes on ... doesn't anyone value conservatism these days ?

[dubbleyew eight]

john ....concentrate.

the subject is stalling a Cessna 172 at low level.

my examples are from flying and observing aircraft in a similar league to the 172. ie light aeroplanes.

your examples are way out of the scenario envisaged.

in my Tailwind (lighter than a 172) you will immediately start flying again if power is applied right at the point of stall. ...but obviously not after the nose has dropped.

[john_tullamarine]

john ....concentrate

Hopefully, even in my dotage .. I still can do that at least some of the time ...

The references apply to certificated lighties ... the Electra is filed away in my memory archives .. wonderful time of my life. For the amateur builts etc., some can be considerably worse and the Regulator's TP/FTE have, over the years, spent much effort in endeavouring to convince folks out there busily building birds to emulate FAR 23 as a desirable goal ..

your examples are way out of the scenario envisaged

I suggest not ... the concerns are VERY real and well known to the flight test community.

My only recollection of the Tailwind is from a flight with Peter Furlong about a million years ago .. he came along so I didn't kill myself ... does yours fly quite nicely with a huge yaw angle ? Quite interesting, I thought, at the time ...

[VH-XXX]

Most aeroplanes have a pitch up tendency associated with applying power, amplified by low airspeed and flaps, this can create a much deeper stall than a power off clean stall.


Lesson 2, primary and secondary effects of controls...

[Jack Ranga]

Cuz, do you know anything about the RV10 with the pod?? It looks **** but haven't seen it before?

[Jack Ranga]

And it probably stalls bad!

[LeadSled]

Mandated Spin Training | The House of Rapp (http://www.rapp.org/archives/2013/12/mandated-spin-training/)

Folks,
Well worth a read.
Tootle pip!!

[Kharon]

One 'stall' element, often poorly understood. Particularly when discussing the 'tail' being stalled rather than the 'mains'. Anyway, the link gets you back to the basics.

Relative Wind. (http://selair.selkirk.bc.ca/training/aerodynamics/definitions.htm)


All motion of an airplane that is relevant in aerodynamics is motion through the air. The air itself may be moving over the ground, and that is called wind. But the airplane does not experience wind. An airplane is like a fish swimming in a river, or lake, or ocean. If the water is moving the fish does not know that, it just drifts along with the current. The IFR navigation section of ProfessionalPilot.ca has some interesting simulations that further clarify this point.

When a model airplane is placed in a wind tunnel a fan is used to blow air over the model. The model itself does not move. When an airplane flies through the sky the air as essentially a stationary gas (it is recommended that you completely forget about wind) through which the airplane moves. But from the airplane's perspective the situation is just like the wind tunnel. The air appears to flow over and around the airplane in EXACTLY the opposite direction and speed to the direction and speed of the airplane's motion. This apparent airflow is called the Relative Wind.

All of aerodynamics depends on the relative wind. The relative wind is always equal to the true airspeed (TAS) but in the opposite direction. I have heard many amusing arguments as pilots try to convince each other that groundspeed is the proper measure of energy, but this is totally wrong. All energy measurements are relative to a frame of reference. When you drive a car the frame of reference is the earth, because it is the earth that supports the car and from which friction is used to move and stop it. We don't expect to have worse accidents if we crash going eastbound than westbound even though we could say we are driving backwards when eastbound, due to the earth's rotation. Similarly the airplane does not climb faster, or carry more weight with a headwind. It is an AIRplane, and as such its motion must be measured relative to the air. The only time groundspeed matters is for determining range, or when crashing (because at the moment of the crash the AIRplane stops flying, and becomes a GROUNDplane - so, don't ever crash with a tailwind.)

In summary then:

Relative wind is the airflow opposite to the direction of flight and equal in magnitude to the true airspeed.

[Oktas8]

I went to that link LeadSled, but the author didn't convince me.

Flying a massive airliner with hundreds of people on board? No spin training required; Well, yes. A spinning airliner is usually unrecoverable. Better stall training would be great though.

By the late 1940′s, conventional wisdom was that the training itself was leading to more accidents than inadvertent spins occurring in the wild. Conventional wisdom, and statistics. The author doesn't address how he would avoid this distressing statistic in future, if he had his way.

I'd encourage anyone here to do aerobatics; it raised me from a poor pilot to an averagely competent one. (Dubbleyew eight - perhaps it might do the same for you... :E ) But throwing more mandatory exercises into an already tight syllabus isn't the answer IMO. Teaching the teachers how to teach stalling is a good starting point, and within CASA power.

[john_tullamarine]

Lesson 2, primary and secondary effects of controls

Perhaps .. but I suspect that very few pilots have any idea of why in this case

[43Inches]

in my Tailwind (lighter than a 172) you will immediately start flying again if power is applied right at the point of stall. ...but obviously not after the nose has dropped.

Watched a student try to do just that in a 172, not enough rudder and over it went inverted. 152s do it almost on cue if you try full power at the stall and don't coordinate, easiest way to teach incip recovery is let the student do it.

Many other light trainers with higher power engines, short rudder moment arm, will (yaw)roll over almost instantly if you are not spot on with the rudder. Throw in aircraft that don't have low speed design fixes like offset fin/engine mounting, washout, stall strips and differential/frise ailerons etc... and it makes for a fun day in the office when students come in thinking they can recover from a stall with zero height loss.

The point of stall training foremost is to reinforce that all you have to do is lower the angle of attack, that is lower the nose/release back pressure, after that you are unstalled. What you do after that is dependent on the situation, if it yawed/rolled coordinate it back to level flight, if minimum height loss is desired then smoothly add power coordinate rudder and raise the nose back to a climbing attitude. Confusing the situation by adding too many things to do at once and the student will inevitably forget the main principle.

Don't confuse this with a drill to recover from an unwanted stall warning indication in flight where by you recognise the approaching stall, smoothly add power whilst coordinating controls to maintain level flight. In this case you should be able to maintain level flight. All you are doing here is acknowledging you got to slow and use normal flight principles to go faster.

[VH-XXX]

Not really related but I love stalling in my BFR's, young instructor on board, I point that 172 up towards the sky with flaps on and by golly does it let go at the stall. I then raise my arms in the air, scream out then bear hug the instructor. Once they overcome the initial shock sometimes laughter follows. We've never flipped during my signature stall but I'll keep that in mind for my next BFR that is due shortly :cool:

[LeadSled]

Oktas8,
Quite simply, the "conventional wisdom" of the day was wrong, it was never true that spin training caused more accidents than spins in normal operations.
Ask any glider pilot about the value of spin and recovery training, and whether the training has a significant (or any) accident history.
Tootle pip!!

[Oktas8]

Well, ok LeadSled. I'm slightly dubious, but you may well be right about the statistics; I have no statistical analysis to back me up.

However, the Air Safety Foundation, as quoted by AOPA (http://www.aopa.org/News-and-Video/All-News/2003/November/8/Air-Safety-Foundation-report-offers-stark-warning-on-spins-and-stalls.aspx), do seem to support the FAA in rejecting mandatory spin training for powered flight licenses. I accept that gliding is & should be a different case, due to the different aerodynamics and prolonged time spent manoeuvring close to the stall.

Fatal stall/spin accidents most often begin at or below traffic pattern altitude... From that altitude, even pilots with aerobatic training stand virtually no chance of recovery. Spin training for private pilots ... appears to be of little benefit in reducing the incidence of stall/spin accidents... Stall/spin accidents, many in training, have declined dramatically since the elimination in 1949 of mandatory spin training for private pilots.

Bringing this back onto thread, at what height do glider pilots practise stalling? For training that is, not for experienced pilots having fun.

[ForkTailedDrKiller]

Bringing this back onto thread, at what height do glider pilots practise stalling?Not relevant to the OP.

You cannot compare the spinning characteristics of a Blanik versus a Traumahawk (or a C172) - they are worlds apart.

Yep, I have lots of rotations in both.

Dr :8

[Oktas8]

I know that.

But I would still like to know the answer: above what height are glider pilots taught stalling?

Would you tell me please?

[Tankengine]

Recovery for gliders by 1000' as a minimum.
However - most instructors would do it higher anyway, especially if lift around for "free" altitude.:ok:

[MALT68]

From the Gliding Federation of Australia (GFA)
Manual of Standard Procedures, Part 2 – Operations December 2012

Page 11

8.1.10 Aerobatics
Before engaging in aerobatic manoeuvres the pilot in command of a sailplane shall ensure that:
(a) The proposed manoeuvres are permitted by the sailplane's Certificate of Airworthiness;
(b) All occupants of the sailplane are secured with correctly-adjusted safety harnesses;
(c) The safety harness of any unoccupied seat is made secure so that it does not foul any controls of the sailplane;
(d) All loose articles are removed from the sailplane or made secure in the sailplane; and
(e) The proposed manoeuvres will not bring the sailplane into close proximity with other aircraft (CAR 155(4)).
The GFA pre-aerobatic check is at Appendix 1.

Pre Aerobatic Check
page 61


PRE AEROBATIC CHECK HEIGHT – Sufficient for recovery by 1,000ft AGL.
AIRFRAME – Flaps, airbrakes, undercarriage set as required. Trim as required. Hatches and vents closed and locked as appropriate.
SECURITY – Harness secure. Loose objects stowed.
LOCATION – Clear of built-up areas, cloud, controlled airspace.
LOOKOUT – 180o plus 90o turns checking carefully around, above and underneath. Do not do a 360o turn.

[Runaway Gun]

How do glider pilots recover from the stall without an engine to blip? ;)

[MALT68]

You don't need a motor to recover from the stall!
You recover from the stall by reducing the AoA to below the critical angle as in most other aircraft.

Excerpt from GFA Instructors' Handbook.

Airborne demonstrations and student practice
“We always carry out a “Pre-aerobatic check” particularly making sure there are no other
aircraft nearby, especially below... To make the glider stall, bring the nose above the normal
glide attitude and keep it there by gently and progressively bringing the stick further and further
back... Notice that the speed and nose are getting less, the controls are becoming less effective
and you may feel the onset of buffeting over the tail section and/or rear fuselage… There’s the
stall. The nose drops even with the stick right back... We move the stick progressively forward to
recover, speed increases and we fly it smoothly out of the dive... You will note that we were
unable to bring the nose up until we regained flying speed.”
The foregoing description of a typical stalling exercise covers the case of a glider which has a
natural nose-drop tendency at the stall. Note the key point - in spite of the stick coming back the
nose drops. In the case of a glider which does not have a natural nose-drop tendency (e.g. Twin
Astir), the key point is the stick arriving on the back stop and the variometer showing about 600 to
800 ft/min rate of descent.
Similarly, if a wing drops before the nose-down break occurs, this becomes the key point and
should be treated accordingly.
The recovery in all cases is identical - smooth progressive forward movement of the stick. It is not
sufficient to allow any natural nose-down tendency the glider may have to “self recover” from the
stall. Positive action must be taken by the pilot. Neither is it sufficient to move the stick forward
to some pre-determined point - the progressive forward movement must continue until the pilot
recognises that the wing is unstalled.

[Oktas8]

Thanks guys. 1000' is quite low - not so much for spin safety I'm thinking - but for recovering to an airfield if you lose more height than expected. But I guess mostly the whole (rural) world is your landing field in a glider! :ok:

I have conducted stalls at min. 1500' agl for flight testing, with the approval of the flying school and the relevant regulator. But 2500' to 3000' was more usual for training, even in that part of the world. I also failed at least one would-be instructor (nice guy, shame about his nerves) for briefing me 2500' agl minimum height, then conducting the demonstration stall at 1000' over rising ground. I was more concerned about his awareness than an arbitrary number in the Ops Manual.

I mention these examples to show the OP that 3000' is not the only standard. But in Australia, I would conform to general expectations; there's no compelling reason to do otherwise. Why single yourself out without powerful reason?

[LeadSled]

How do glider pilots recover from the stall without an engine to blip?

Runaway Gun.
By reducing the angle of attack below the stalling angle of attack, the same way any aircraft recovers from a stall.
I sincerely hope you are only an interested bystander, and not actually a pilot.
Tootle pip!!

[Jabawocky]

I think he was posting with tongue firmly in cheek ;)

I can't believe this thread is on its 4th page :uhoh:

[Ratshit]

How do glider pilots recover from the stall without an engine to blip? http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/wink2.gif

A better question is how can a glider stall at all - it doesn't have an engine! :confused:

Rat :cool:

[Ultralights]

why is stall and spin recovery being confused as the same thing?

[pineappledaz]

We use 2,500, and that low due to airspace restrictions. Wouldn't want to be any lower wing dropping in a c152, c172 is pretty much the same. if you don't recover there is a pretty good chance going into a spin/spiral and you are going to need some altitude before you becoming fixated on the ground rapidly approaching.

[Jack Ranga]

When did the stall become so complicated? Did I miss flying school that day?

[Howard Hughes]

Bout 50 feet should do ya! :)

Matt Hall's amazing recovery - YouTube (http://youtu.be/5CB27K-wIsM)

[Jack Ranga]

Howard, Matt gave a talk at AUSFLY this year, it was one of the most entertaining, motivating & intriguing aviation talks I've listened too. He talked in depth about that incident, the full story was fascinating ;)

[Centaurus]

Wouldn't want to be any lower wing dropping in a c152, c172 is pretty much the same

I understand the FAA certification of these aircraft by the test pilots includes the limitation that any wing drop at the point of stall must not exceed ten degrees. It also states the technique that must be used by the test pilot for entering the stall. Normally something like a speed reduction of one knot per second.

So during flying school training, if a wing drop occurs at the point of stall and exceeds ten degrees, the aircraft is by definition un-airworthy and the maintenance release must be annotated as such. Usually a significant wing drop at the point of stall can be traced to defective rigging which is all the more reason to write up the defect before the next poor bugger kills himself. Few students or other pilots will do that in case they get the DCM by the CFI/owner/manager.

Of course if the pilot decides to haul the nose very high during the stalling practice in order to save time and get it to stall more quickly, then that invalidates the certification process.

[ranmar850]

As an earlier poster said, doing a basic aerobatics endorsement will do wonders for your flying. Puts those "scary" stalls in perspective:) You haven't lived until you've hammerheaded a botched wingover in an Aerobat :eek: it did, however (in my case at least) engender an enthusiasm which needed kerbing--afterwards, I went for a check ride in the local outfits brand new C172, and when asked to simulate a stall, at safe altitude, stood it on its tail. And was sternly admonished, rightly so, by the chief pilot, to tone it down. Best money, post PPL, that I ever spent on flying.

[Ultralights]

exactly, the best investment in your flying, en EMT course, or basic Aeros, and a decent engine course! will put to bed countless old wives tales handed down through the generations, doing the EMT and and engine course will prove just how wrong some are, and dangerous. cheap life insurance.

[43Inches]

So during flying school training, if a wing drop occurs at the point of stall and exceeds ten degrees, the aircraft is by definition un-airworthy and the maintenance release must be annotated as such. Usually a significant wing drop at the point of stall can be traced to defective rigging which is all the more reason to write up the defect before the next poor bugger kills himself. Few students or other pilots will do that in case they get the DCM by the CFI/owner/manager.

This is only the case if the aircraft consistently had this tendency under the conditions required for the test flight. Stall practice requires stalling in various conditions including approach config, add a little flap and power and you are almost guaranteed a significant wing drop in a 152 unless perfectly coordinated.

A great number of factors outside (or inside) of the aircraft can cause one wing to stall before the other.

However a correctly handled/coordinated 1g power off level stall in these aircraft should barely roll at all.

I think the comment relates to that a 152 and 172 are easy to put into a spin situation if miss-handled as opposed to a PA28 which resist wing drops very well.

[QJB]

Wing at 16 deg AOA, stalled, wing at 15 deg AOA, unstalled. Height loss about 10ft at most, as you move the stick fwd a fraction to effect the 1 deg pitch change.

Now going from 16 deg AOA stalled to 0 deg AOA nose at 20 deg negative pitch dive while pushing full power, then you will lose far to much height than actually needed to recover..


What method is taught the most and why?

And which method of stall recovery would you prefer if you stall on mid or short final? (Yes, final, not finals, you can only fly 1 final at a time)
bury the nose into the ground recovering, or just releasing enough back pressure to get the wing from 16 to about 15 or 14 deg AOA, where it will still fly happily, unstalled. Even in a turn.... assuming you know how to use a rudder and the ball is centered.


Amen!

Based on the way I've seen stall recoveries taught in most flying schools I'd like to be above 3000 feet. Based on moving the stick just forward of the stalling position, I'd quite happily venture below it.

[43Inches]

The 3000ft has nothing to do with a normal stall recovery, it is there in case of severe miss-handling which does happen frequently during basic training.

[Tankengine]

While we are talking stalling, from discussion with some newbies it seems they recover at the point of stall.
Next time you are up in a suitable aircraft, above 3000' by a margin:

Try stalling and NOT recovering straight away! :eek::E
Hold full back stick to keep the aircraft in the stall for as long as you like, keeping wings level with rudder ( or even aileron - give it a go!) until, when you wish to recover, simply move the stick/column forward to reduce the angle of attack and recover, power use once wing unstalled.:ok:

I believe there are even instructors out there who have never done this simple demonstration of how it is the angle of attack you need to reduce.:ugh:

[john_tullamarine]

Following up on Centaurus's post to clarify a few points ...

(a) C172 TCDS (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/a9c23e984754258e86257acc0077095f/$FILE/3A12_Rev_83.pdf)

(b) a quick read through the TCDS, for the earlier models (the later examples are left for others to decipher), suggests that the certification basis was CAR 3

(c) the relevant flight test guidance material has been published in various documents over the years and I'll leave it to you to track them down .. for this discussion the regs give enough information

(d) certification stall recovery requirements haven't changed all that much over the years.

If we go back as far, say, as CAM3 (that's older than I am) the words are

During the recovery portion of the maneuver, it shall be possible to prevent more than 15 degrees roll or yaw by the normal use of controls, and any loss of altitude ill excess of 100 feet or any pitch in excess of 30 degrees below level shall be entered in the Airplane Flight Manual.

and, if we jump ahead, say, to the present FAR 23

During the entry into and the recovery from the maneuver, it must be possible to prevent more than 15 degrees of roll or yaw by the normal use of controls except as provided for in paragraph (e) of this section [para (e) is not relevant to this discussion]

(e) what that means is that the test program very likely used whatever aileron was needed to constrain roll to not more than the specified 15 degrees. Depending on which particular set of rules might be pertinent, this can be ruthlessly anticipated.

(f) if one uses the typical pilot training stall recovery (which has nothing to do with certification thinking and is of rather questionable parentage) one ought not to be surprised when/if one finds oneself on one's back with a good view of the heavens ...


Hold full back stick to keep the aircraft in the stall for as long as you like

Now, that's quite at variance with the certification requirements and expectations. Don't be surprised if you get bitten on the tail from time to time ...

keeping wings level with rudder

Potentially dangerous - rudder and spins tend to go together.

The certification expectation is that rudder is used to maintain heading, ie constrain yaw excursions