Gliding - airbrakes in final turn
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Gliding - airbrakes in final turn
Have been told this is a bad idea, following my first flight in a Discus where I cracked them open as I was turning final
Have been thinking about it since and not sure the reasons why? Is it something to do with the inside wing flying closer to stall speed and so a sudden loss of lift (area) could cause it to stall? But then given the high approach speed I would imagine this is less likely
Is it the same on all glider types?
Have been thinking about it since and not sure the reasons why? Is it something to do with the inside wing flying closer to stall speed and so a sudden loss of lift (area) could cause it to stall? But then given the high approach speed I would imagine this is less likely
Is it the same on all glider types?
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Trainee instructor courses make a point of stressing that turning final & opening the airbrakes should be two separate actions.
2 reasons are usually given:
a) low airtime/un-current pilots have enough difficulty making a controlled, co-ordinated turn at a constant airspeed without adding the complication of opening the airbrakes.
b) to discourage 'landing lever syndrome', whereby pilots get in the habit of automatically opening the airbrakes as they turn final, a habit which occasionally leads to undershoot accidents. Accident no.11 in the latest S&G may be an example (story here).
So, yes it does apply to all glider types, but the slight increase in stall speed as the airbrakes are opened is not really a factor. It's more the result of years of accident reports where the narrative says something like "I turned onto final approach and opened the airbrakes . . . by the time I realised that I was undershooting and shut the brakes, the glider was too low to reach the airfield".
Instructors are taught to teach pilots to turn final, get the glider settled down in a stable approach and not to open the airbrake until they're on the 2/3 airbrake approach path. It's just one of those things, however safely you do it opening the airbrakes while turning final is considered to be a bad habit to get into.
2 reasons are usually given:
a) low airtime/un-current pilots have enough difficulty making a controlled, co-ordinated turn at a constant airspeed without adding the complication of opening the airbrakes.
b) to discourage 'landing lever syndrome', whereby pilots get in the habit of automatically opening the airbrakes as they turn final, a habit which occasionally leads to undershoot accidents. Accident no.11 in the latest S&G may be an example (story here).
So, yes it does apply to all glider types, but the slight increase in stall speed as the airbrakes are opened is not really a factor. It's more the result of years of accident reports where the narrative says something like "I turned onto final approach and opened the airbrakes . . . by the time I realised that I was undershooting and shut the brakes, the glider was too low to reach the airfield".
Instructors are taught to teach pilots to turn final, get the glider settled down in a stable approach and not to open the airbrake until they're on the 2/3 airbrake approach path. It's just one of those things, however safely you do it opening the airbrakes while turning final is considered to be a bad habit to get into.
Glider pilots are taught to look over the nose most of the time when turning so as to maintain the correct attitude (and hence airspeed). When turning final there is a tendency to look at the landing area instead. This frequently results in the nose rising a bit and airspeed consequently being reduced. Many gliders tend to change attitude when the airbrakes are opened - with some the nose drops and others the opposite. Superimposing that effect on a possible wrong attitude due to the pilot looking at the landing area can lead to a dangerous loss of airspeed.
To mitigate the risk pilots are advised to open air brakes preferably after the final turn is complete and when on a 2/3 path as mentioned in the earlier post or, if excessively high, before the final turn - but not during the turn. They are also encouraged to do a well banked turn (say 30 degrees) since there is evidence that it is more difficult to spin from such a turn as compared to a flat turn if speed is lost.
To mitigate the risk pilots are advised to open air brakes preferably after the final turn is complete and when on a 2/3 path as mentioned in the earlier post or, if excessively high, before the final turn - but not during the turn. They are also encouraged to do a well banked turn (say 30 degrees) since there is evidence that it is more difficult to spin from such a turn as compared to a flat turn if speed is lost.
Here in the states a higher, steeper approach is the norm. We partially open spoilers/divebrakes on downwind and leave them open (as required) until we stop. Ideally I'd like to get them open about 1/3 then not have to make any further adjustments. However, if I do need to adjust, I am about in the middle of my performance curve and can steepen or flatten out my glide. Any land short accidents I've seen here were not a result of using spoilers before finals, they were a result of being out of gliding range of the field but trying to stretch it anyway.
If I ever get to the other side of the pond it would be interesting to see what they teach there. It seems foreign to me.
-- IFMU
If I ever get to the other side of the pond it would be interesting to see what they teach there. It seems foreign to me.
-- IFMU
Instructors are taught to teach pilots to turn final, get the glider settled down in a stable approach and not to open the airbrake until they're on the 2/3 airbrake approach path
And what happens when you have a cable break at a small site, or an aerotow rope break at a very awkward height? You may well have to use large need large amounts of spoiler/airbrake in a final turn to complete the proceedure safely.
If the pilot cannot be relied upon to use airbrakes in a final turn he is not really ready to fly alone!
BGA and air brakes.
I believe Tinpilot is right to say that the BGA want to see trainee instructors demonstrate approaches that way. It doesn't mean to say that's the way the BGA want to see every appraoch. There can be a number of reasons why you would want/need to use the airbrakes in the final turn. If you need 'em, use 'em!
Last edited by snapper1; 5th May 2010 at 17:53. Reason: Comedy spelling.
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another point -
Okay, you have executed a well banked final turn no lower than 300 feet, and have nailed the approach speed for the conditions of the day. However, as your reference point begins to slide gently up the canopy, you realise "o dear, I think I am undershooting!"
PUT THE BRAKES AWAY COMPLETELY! NOW!!!. and when re-established on the correct approach path, you may open the airbrakes to the appropriate setting, which is usually 2/3, in a K-13, to the height of an average elephant. Now looking well ahead, begin the progressive roundout, or flare, resulting in gently settling, to the perfect landing. Fully stalled, of course, to avoid any chance of the dreaded balloon!
Ask your instructor to demonstrate first, the perfect landing. Then fly again, and this time, you do the perfect landing.
A good landing is a stall near the ground.
However, OVERSTEER, if you are flying a discus, you hardly need to worry about opening the airbrakes whenever you jolly well like, the discus is an advanced glider with no vices, and as you of course are well experienced, and flying at correct airspeed even in a turn onto final approach, highly unlikely to have any problems. These warnings are aimed at beginners.
PUT THE BRAKES AWAY COMPLETELY! NOW!!!. and when re-established on the correct approach path, you may open the airbrakes to the appropriate setting, which is usually 2/3, in a K-13, to the height of an average elephant. Now looking well ahead, begin the progressive roundout, or flare, resulting in gently settling, to the perfect landing. Fully stalled, of course, to avoid any chance of the dreaded balloon!
Ask your instructor to demonstrate first, the perfect landing. Then fly again, and this time, you do the perfect landing.
A good landing is a stall near the ground.
However, OVERSTEER, if you are flying a discus, you hardly need to worry about opening the airbrakes whenever you jolly well like, the discus is an advanced glider with no vices, and as you of course are well experienced, and flying at correct airspeed even in a turn onto final approach, highly unlikely to have any problems. These warnings are aimed at beginners.
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I have asked a number of instructors whether airbrakes can be used in the final turn. Some advise yea and some nay as the discussion above shows, and they all offer good logical reasons either way. The last instructor I asked said "I don't care where you use airbrakes" (I think the message was use them properly whenever needed).
In our motor glider/tug it is usual to set the brakes open to the first detent either on downwind or base and work them from that position.
In our motor glider/tug it is usual to set the brakes open to the first detent either on downwind or base and work them from that position.
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I know some instructors are quite hot on the use of the 'going in to land' lever.
It is important to be sure that you can actually reach the airfield before using the brakes. It is easy to use them without thinking, then get caught in serious downdrafts and end up short of the airfield. I still have bits of a Skylark 4 whose pilot made that mistake.
But if you are sure, use the brakes
It is important to be sure that you can actually reach the airfield before using the brakes. It is easy to use them without thinking, then get caught in serious downdrafts and end up short of the airfield. I still have bits of a Skylark 4 whose pilot made that mistake.
But if you are sure, use the brakes
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Hi guys,
Haven't been in a glider for a while but I agree with Snapper1.
Once the field is made, if you need 'em, use 'em!
I have the (maybe bad...) habit of sideslipping a lot. I think it's fun. Therefore sometimes I go into final a little high. Some gliders are more stable slipping with airbrakes popped out, so while I'm in the turn from base to final, I pop the brakes and go directly into the slip.
Airbrakes, just tools to your disposition. How you use them is up to you
Just my 2cts...
Happy landings!
Haven't been in a glider for a while but I agree with Snapper1.
Once the field is made, if you need 'em, use 'em!
I have the (maybe bad...) habit of sideslipping a lot. I think it's fun. Therefore sometimes I go into final a little high. Some gliders are more stable slipping with airbrakes popped out, so while I'm in the turn from base to final, I pop the brakes and go directly into the slip.
Airbrakes, just tools to your disposition. How you use them is up to you
Just my 2cts...
Happy landings!
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Another issue to onsider is workload management. Once you crack the brakes open your brain is committing a little bit of processing power to keep your hand in place/watch for pitch changes, etc. This is at the point at which your workload in the circuit is increasing already - lookout, speed control, rate of descent, lookout, rate of turn, undershoot/overshoot? gusting, increased/decreased sink rate, lookout, landing area, other gliders in circuit, where's the tug? is there launching taking place?, lookout, etc. etc. Why would you intentionally want to increase your workload at this point?
Most competent pilots should, by the time they're solo, be able to deal with the increased workload but that doesn't mean they need to. Indeed, adverse conditions aside, I always suggest to pupils that if they've ended up in a situation where they need to use airbrakes in the turn then they've misjudged the circuit already. If they don't have the skills to manage a simple circuit, why should I believe that they have the skills to deal with an increase in workload?
Most competent pilots should, by the time they're solo, be able to deal with the increased workload but that doesn't mean they need to. Indeed, adverse conditions aside, I always suggest to pupils that if they've ended up in a situation where they need to use airbrakes in the turn then they've misjudged the circuit already. If they don't have the skills to manage a simple circuit, why should I believe that they have the skills to deal with an increase in workload?
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Here in the states a higher, steeper approach is the norm. We partially open spoilers/divebrakes on downwind and leave them open (as required) until we stop. Ideally I'd like to get them open about 1/3 then not have to make any further adjustments. However, if I do need to adjust, I am about in the middle of my performance curve and can steepen or flatten out my glide. Any land short accidents I've seen here were not a result of using spoilers before finals, they were a result of being out of gliding range of the field but trying to stretch it anyway.
If I ever get to the other side of the pond it would be interesting to see what they teach there. It seems foreign to me.
-- IFMU
If I ever get to the other side of the pond it would be interesting to see what they teach there. It seems foreign to me.
-- IFMU
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I am always conscious of opening the brakes only when I'm sure I need them - I think in this case I started the circuit a bit too high given the performance of the Discus. I will be vigilant however not to get into the habit of just opening them without looking.
cats_five I did wonder if this sort of approach was normal in the States, being honest it scares the hell out of me!
YouTube - cockpit shot of glider landing
cats_five I did wonder if this sort of approach was normal in the States, being honest it scares the hell out of me!
YouTube - cockpit shot of glider landing
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DIAGONAL LEG? not over there!
Trouble is, most gliding in the US is a minority sport, sharing the very active airfield with a lot of power planes. Which believe firmly in doing proper "patterns". Announcing their intentions and positions, hopefully, over unicom. (remembering to mention which airfield they are planning to visit).
Which means gliders have to conform to local practice. Downwind, 90 degree turn onto base, 90 degree turn on to final approach.
Also, one of the main gliders used over there for instruction is a tin elephant ...forget the name, but nimble it is not. And the spoilers don't help a lot either.
Worst of all, the sport is regulated by the FAA, which has so little understanding of it that instructors are not even required to do cross country.
The diagonal leg in the UK finally recognised normal safe practice for gliders; just cut off the corner! you never loose sight of your field that way.
I still remember sitting in the back of the K-13, developing a serious case of the leans, wondering if the student would turn base before we were completely out of range.......before they changed the rules at last!
Which means gliders have to conform to local practice. Downwind, 90 degree turn onto base, 90 degree turn on to final approach.
Also, one of the main gliders used over there for instruction is a tin elephant ...forget the name, but nimble it is not. And the spoilers don't help a lot either.
Worst of all, the sport is regulated by the FAA, which has so little understanding of it that instructors are not even required to do cross country.
The diagonal leg in the UK finally recognised normal safe practice for gliders; just cut off the corner! you never loose sight of your field that way.
I still remember sitting in the back of the K-13, developing a serious case of the leans, wondering if the student would turn base before we were completely out of range.......before they changed the rules at last!
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There are a few clubs in the UK where gliders and power share, and they deal with it by separating the traffic - gliders fly left-hand and power right-hand circuits or vice versa. So, power can fly the shape circuit they think appropriate and gliders the shape we think is appropriate. Much safer IMHO than mixing the two and making gliders 1) get too low and 2) lose sight of the reference and landing areas.
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This sounds like it's becoming a bit like the debates about:
All things that should be avoided when experience is limited - but all things that are useful tools when used correctly.
When I had advanced to Bronze 'C' level my instructor would sometimes place me in a "bad" circuit position (often too close in) - the only requirement was I had to judge deployment of airbrake so that I would go from 0 to 2/3 and was then only allowed to make very minor adjustments. Sometimes this did mean deploying airbrakes half way through the final turn.
To allow people to asses my comments I have around 220 hours / Silver 'C' in gliders (mostly in an Open Cirrus) - so relatively inexperienced.
OC619
- Deploying flaps in a turn
- Over square for CS props
- Side slipping under XXX' agl
- Running lean of peak
- Flying outside the demonstrated X-wind component
- ....
All things that should be avoided when experience is limited - but all things that are useful tools when used correctly.
When I had advanced to Bronze 'C' level my instructor would sometimes place me in a "bad" circuit position (often too close in) - the only requirement was I had to judge deployment of airbrake so that I would go from 0 to 2/3 and was then only allowed to make very minor adjustments. Sometimes this did mean deploying airbrakes half way through the final turn.
To allow people to asses my comments I have around 220 hours / Silver 'C' in gliders (mostly in an Open Cirrus) - so relatively inexperienced.
OC619
The initial part of your circuit will be a bit higher and steeper, but not the last bit. Also you are burning away height when there is still the possibility of hitting sink (possibly major sink) in the circuit. The UK circuit will be shallower until the point at which airbrakes come out, then steeper. There is also a diagonal leg so the landing site is always in view, which I gather is not necessarily done in the US.
Originally Posted by cats_five
A friends description of flying at a US glider site left my blood running cold - he saw a lot of landings with very little airbrake and quite a lot of PIOing.
Originally Posted by oversteer
cats_five I did wonder if this sort of approach was normal in the States, being honest it scares the hell out of me!
Originally Posted by cats_five
There are a few clubs in the UK where gliders and power share, and they deal with it by separating the traffic - gliders fly left-hand and power right-hand circuits or vice versa.
I can assure you that the FAA cares little if I fly a square pattern with my glider or not. The regulations here are not very burdensome, whether I fly a glider, power, helicopter, IFR, whatever.
I'm beginning to think (hope, actually) that my impression of the practices across the pond are as skewed as some of your impressions are of flying over here!
Like OC619, I'm relatively inexperienced with a couple hundred hours or so. Probably about half in the Blanik L33 I used to own.
-- IFMU
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True, I am burning away height when there is a possibility of sink, but I have height to burn. If you are low and hit sink, what do you do? Do you have height to burn, or is there just no sink that comes up low? We typically don't do a diagonal leg, but I have never lost sight of the runway. I mean, it's right there out my window.
<snip>
<snip>
As to losing sight, if the reference point is near the threshold then you don't have to fly far downwind past it for seeing it and using it to judge your circuit to get harder than it need be.
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Dear IMFU
Theres only one thing for it, you must pay us a visit! Volcanos permitting, of course.
We enjoy being hospitable to Yanks at Shenington Gliding Club, near Banbury. Especially if you can be here for the 4th of July, I am the only resident of US origin in the club, and we need to show the locals how to play baseball properly.
(One nice thing about posting on these humble forums is they never tell us off for thread creep!)
So I shall creep some more. Started gliding in l983, at Booker. Where traffic is separated as mentioned by cats five, except for helicopters who cannot be trusted because they can stop in midair and go backwards, so you cannot trust them not to cross your approach!
Accumulated a lot of time since then, 1,800 in gliders, 1,400 in power, because I never never stopped flying, and instructing and participating in competitions, and flying in the Alps, and rock polishing in Wales and climbing in wave in Aboyne, etc etc etc. It is a wonderful scene in the UK for gliding altogether, the fields are friendly and the farmers speak English, sort of.
The bad news is I am getting older, (good news, considering the alternative of course) and in the course of having a knee replaced, thanks to the NHS, developed a problem with vision which has finished my instructing career, except on these forums. If I can convince my doctor that I am fit to drive a car next week, I will be back in a single seater, you bet, and they may permit me to supervise junior instructors from the ground. Watch this space!
We enjoy being hospitable to Yanks at Shenington Gliding Club, near Banbury. Especially if you can be here for the 4th of July, I am the only resident of US origin in the club, and we need to show the locals how to play baseball properly.
(One nice thing about posting on these humble forums is they never tell us off for thread creep!)
So I shall creep some more. Started gliding in l983, at Booker. Where traffic is separated as mentioned by cats five, except for helicopters who cannot be trusted because they can stop in midair and go backwards, so you cannot trust them not to cross your approach!
Accumulated a lot of time since then, 1,800 in gliders, 1,400 in power, because I never never stopped flying, and instructing and participating in competitions, and flying in the Alps, and rock polishing in Wales and climbing in wave in Aboyne, etc etc etc. It is a wonderful scene in the UK for gliding altogether, the fields are friendly and the farmers speak English, sort of.
The bad news is I am getting older, (good news, considering the alternative of course) and in the course of having a knee replaced, thanks to the NHS, developed a problem with vision which has finished my instructing career, except on these forums. If I can convince my doctor that I am fit to drive a car next week, I will be back in a single seater, you bet, and they may permit me to supervise junior instructors from the ground. Watch this space!