Avoiding spins from base to finals
 

After reading the 'instructors who refuse to spin' thread on the instructors forums:

What is the best way to ensure that you DON'T inadvertently spin the aircraft on turn from base to finals?

Understand about not lifing nose, or letting airspeed bleed off with flaps extended, but is there a way to really ensure that you don't enter one? (This has always been a thorn in my side)

Also, should you be unfortunate enough to spin at this point, is there ANYTHING at all you can do, being so close to the ground?

<apologies if this is in the wrong forum>

Airspeed and Bank Angle. Choose the right numbers for your aeroplane and Bob's your uncle.

If you enter a genuine spin at or below 1000 AGL, you can forget any real hope of recovery.

As they drum into you during the PPL

" Airspeed Airspeed Airspeed"

Nail your airspeed and bank angle & you should always be ok.


If you have concerns or worries grab an instructor and bash the circuit you can't beat it for making you confident & competent.


EL

As has already said the key is airspeed. To spin you have to stall and to stall you have to have a high AoA. Just keep an eye on your airspeed, make sure its what it needs to be. Also try and avoid uses of extra rudder when near the ground. Its all common sense really.

As for what to do if you spin, well the first thing I would do is try and recover. Its the only thing you can do. Depending on height and a/c you might be lucky, you might not. Altho I don't advise testing this at low level lol.

FCI's article on the subject and another by FCI.
Rich Stowell has something to say about this too but you really need Rich Stowell's video Stall/Spin Awareness to really get the point.

The aircraft CAN NOT spin if it is flown in a balanced turn. So fly accurately - ball in the middle. If it is too slow, it could stall but if it is being flown in a co-ordinated (rudder/aileron) fashion it will not spin.

At a thousand feet, unless you were in very current practice, you'd probably buy the farm.

Stik

G_String, firstly, if you fly at the airspeeds in the pilot operating manual and fly a co-ordinated turn which is essentially keeping the ball in the middle then you won't stall.

The best bet for you is to find an instructor who is happy to take you into a full stall rather than incipient stall and to let you see how much abuse you need to give a spam can to make it stall and what warnings there are.

The easy answer...
 

Look out the front window!!!

Of course staying keeping the airspeed right and keeping in balance is the key to not spinning. But that's true of any stage of flight.

So what is it that makes the spin more likely to happen at this stage, apart from maybe being a little slower than during the cruise?

It's pilots who are trying to look at the runway during the turn - and therefore not watching the attitude. You will not notice that your speed is wrong nor that you are out of balance if your eyes are not on the horizon!

The issue is that you, naturually, want to see where you are turning towards. But in turning your head to look at the runway, you are looking away from the horizon, and therefore not aware of any changes in attitude or airspeed.

The problem is worse, IMHO, in a high-wing aircraft, because the view of the runway is obscured in the turn, meaning that you probably have to shift around in your seat to see the runway - and this will naturally involve you involuntarilly moving the controls.

Incidentally, I see my students loosing airspeed (in the high-wing Cessnas that I teach in) far more on the downwind-base turn than on the base-final turn. The reason, 99% of the time, is that they are trying to look at the runway to work out when to roll out of the turn. When turning final, the runway is at least ahead of you at the end of the turn, so you don't have to strain to see it. But when turning onto base in a high-wing aircraft you must have some other method of working out when to roll out of the turn. The answer? Before you roll into the turn, pick a feature just in front of the left (or right, for a right-hand circuit) wing. Then start the turn, keep looking ahead, and stop the turn when your pre-selected feature appears in the windscreen. As you roll out of the turn, you can then look at the runway and make adjustments. This will enable you to be aware of your attitude, and therefore your airspeed, right the way through the turn.

To answer the second part of the question, if you ignore all the advice here and get it wrong..... I don't believe there is any way of recovering from a spin at that level in most aircraft before hitting the ground. But the training you get in spin recognition and avoidance as part of your PPL should train you to lower the nose, apply full power, level the wings and climb away well before the situation develops into a full spin. That is precisely why, for the PPL skills test, you are required to recover from this situation at the first sign of the stall, namely either the light buffet or the stall warner, whichever occurs first.

FFF
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If you dont load the wing you wont stall and spin. You can bank as hard as you like providing you have a hefty decent going at the same time (and little back presure on the elevator)

atsa2

I can pull a descending 3G turn in my beastie, mishandle the rudder and she will flick out of the turn (up) or will flick into it (down).


Stik

What you say is of course true Stik, but I think I know what atsa2ltcc is trying to say .... as I'm sure you do (are you playing Devils advocate?)

Most stall and spin accidents at this point are caused by an overshoot of the centre line. A student worried about banking too hard is more inclined to unconciously skid the aeroplane around the turn by adding more rudder. Even with a reasonable airspeed it's quite possible to cause a spin this way. Whilst a high bank angle is normally discouraged near the ground due to the increased stall speed, it's much safer than skidding, and if you have a reasonable amount of speed and don't pull too hard you will be fine. Actually, I hate the use of the term "airspeed" because it is a pretty misleading figure and so heavily influenced by other factors. AoA is much better and it's a shame that a decent AoA indicator has not been developed for light aircraft.

SS

I've said this before, try to be aware of the stick position. If you are getting towards the back stop, you are just about to stall, regardless of airspeed.

I do not have my PPL so ignore me if this makes no sense! - I am trying to finish and get the first milestone!

When I did my Flying Scholarship, I was always taught once you have commited to the "death turn" never increase the bank angle. If you are going to over shoot the runway hold the turn a little longer to turn you back on an intercept heading and re-establish the centreline. If not or you have doubt - Go Around.

It was always said to me that you are going to probably be losing airspeed in the turn, and although you'll be fine at a normal bank angle if you increase it you could increase the stall speed above your current speed. so it's best to keep the stall speed where it is, and if you get buffet reduce the bank angle - and Go Around!

It is a while ago I did this so memories are old... but that's what I remember.

stiknruda..

Read my full post! "With little elevator back pressure". I would be impressed if you could do a 3g decending turn without elevator pressure!

... and so another well-intended thread spirals into a high-G manoeuvre :D

I think you've had the answer G_STRING, packaged in several ways. Watch the bank angle and the airspeed and all will be well. Don't forget that a higher airspeed is required to avoid a stall when the bank-angle is increased. That is what catches lots of people out.

Talk of Angle-of-Attack and loading the wings is much more "right-on Piloty" and in keeping with "grass roots flying", but not very helpful to a low-hours pilot IMHO.

2D

I am slightly concerned that the suggestions for an hour or two of dual with an instructor could be misinterpreted as being sufficient to eliminate the prospect of a classic spin-during-turn-to-final accident.

The fact is that many properly trained, high-time, experienced pilots have been killed in this sort of accident; it is something that we all have to be constantly aware of. You can be the best pilot in the world, but if you are momentarily distracted by something, or fatigued at the end of a long flight, a low-level spin can still bite you.

One of the best discussions of this topic is Leighton Collins' artilce "The Dangers of the Air", which is found near the end of Langewische's classic Stick and Rudder.

There are various AoA systemes available for light aircraft (see e.g. here, here and here, and there are others); but I have never flown an aircraft equipped with one, and I don't know how well they work.

True, MLS. But an hour or two with an instructor would surely be sufficient for understanding the problem, even if it won't eliminate it?

FFF
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Well yes, I suppose so; although come to that, reading about the problem in a book or magazine article would be an even cheaper method of understanding.

I am in no way against dual instruction, which is usually the most effective way to sharpen up one's flying. My point is simply that even a great instructor can only provide limited protection against this potential accident ... constant wariness is really the only reliable safeguard.

Atsa/ss

contrary to how you read my post, I wasn't disagreeing with Atsa - what I was trying to reinforce was that turns need to be co-ordinated.

It was because of the relatively low experience level that some on this forum have that I keep banging on about coordination.

It doesn't matter how fast you are going, if you pull to wings critical (AoA) and then apply too much rudder or too little rudder you will flick/snap and that could just be your entry into your first and last fully developed spin.

Alternatively, if you are going too slowly, the same scenario reoccurs - but only if you mishandle the rudder.

MLS12 - many aircraft have a perfectly good AoA indicator - it is called the stick! The aeroplane will stall with the stick in same position across the range of airspeed!

What I mean, before I get shot down, is that in my aeroplane, with the power at idle and the aircraft decellerating through 60mph with the stick coming back to hold the nose up, the stall break will come at the same stick position as it will if I am accelerating through 120mph, with full power on and pull the stick back.

So once your muscle memory maps arm position to stall - you have your very own built in AoA indicator.


Stik

An hour or two with an instructor who doesn't have a lot of stall/spin/aerobatic time is unlikely to help much.

STIK,
Quite unusual for most aircraft not to spin one way or the other without dancing on the rudders. If you've time to dance on the rudder you've got time to release the back pressure on the stick which is the actual cause of the circumstances you find yourself in.

I believe the key for the final turn is bank angle. Way back when I started gliding I had it knocked into me 'well banked final turn', 'MINIMUM 30 degrees'. This came back to me during commercial training, all turns in the circuit EXACTLY 30 degrees.

So what is the point?
Well, in a glider there is a lot of wingspan which, if you try to cheat, helping get the last bit of turn with a touch of rudder or just fly inaccurately, creates a considerable difference in airspeed over the respective surfaces. If you're already to slow this may be the final nail in your coffin. If you fly too slowly through a steeper turn you get a high rate of descent and the nose drops but all you have to do is level the wings and you're flying again. One way you die, the other you live.

In the commercial training the point was to improve your judgement so that you only made the exact required turn instead of 45 at 30 degrees, 30 at 20 and the final part of the turn at 5 or 10 degrees.

My gliding and training remain fresh in my mind; when I do a visual approach, coming in on base or from 45 degree base, I still wait until what I reckon to be the right moment to make the 30 degree banked turn instead of waffling onto the final course.