Gliders and avoiding them !
 

T'other day I went orf to do a solo navex, departing the overhead from Kemble I decided to dog-leg round Aston Down, noted for it's heaving gliding activity, whilst keeping a SHARP lookout.

Having left Aston Down astern, I was in the clear thought I, oh no, a glider appeared off to my left (having flown overhead me I presume) and then promptly elected to turn right in front of me !

I hung a right, banged the power in and executed a climbing turn to the right, pretty pronto!! Now I know we're supposed to give way to gliders, but c'mon guys, if I had been looking the other way for just a split second, I reckon I would have had a good chance of 'buying the farm'.

Surely avoidance is a 2-way street ! :confused:

That's of course assuming he saw you :(

Maybe he didn't :sad:

VFR,

It very much is!

I am pretty sure that this gliderdriver did not think: 'Let's bank right and I have right of way over the power driver so I will be fine!'

More than likely he did not see you. Especially from the angle you describe it will be difficult to see anything in which is beyond your leading edge.

If he did indeed come from your overhead initially it makes it a bit more difficult to appreciate that he was not aware of you but it does happen to all of us that we miss something.

A salutory lesson in how little we actually see despite keeping a sharp look out can be had by flying a machine with TCAS in the open FIR. Despite 'knowing' (as in bearing and distance) where to look you it can be a devil's job to spot the bogey!.

And before any of your wisecracks pipes up; I do have 20/20 vision, sometimes even without hindsight!

:D

FD

2 gliders out of Dunstable have just flown in to each other close to Lasham. Both gliders crashed. The pilots had parachutes and used them. I don't expect you had a parachute?

Gliders are particularly hard to see because they are white (the RAF has determined that black is best for conspicuity).

I believe they are white to limit weakeneing of the structure caused by exposure to sunlight (UV, specifically, I think).

SSD

Gliders can be found a long way from gliding sites. Flights of over 200 miles are not uncommon. Gliders will spend a lot of time circling under cumulus clouds as this is where the thermals are usually found. Avoid these or keep a good look out when flying under them could be a start.

Quite so. On balance I like having the Avidyne tell me what's out there, but sometimes I feel that the former blissful ignorance makes for more relaxing trips!

It is surprising and worrying how many aircraft you can't see even when TCAS is showing you just where to look.

I would love to have TCAS. Unfortunately, for the £15k+installation one only sees the planes who have a working transponder. And if they are in Mode A only, one gets lots of reports of mostly-low-down traffic which won't bother anyone flying at say 4000ft. There is an awful lot of traffic in the lowest 2000ft; my guess is that most GA traffic, and probably the majority of XP-less planes (excl. gliders), are down there.

One needs to fly under an RIS and hear numerous reports of "unknown level" contacts, to realise there are many planes (WITH normal electrical systems) which either don't have a working XP, don't have it turned on by accident, or don't have it turned on deliberately.

Without compulsory Mode C, TAS/TCAS will only ever help a bit; it won't reduce the need for a lookout, especially as I suspect that those without a working XP are also a lot more likely to be out of radio contact (by choice).

And gliders are the least likely to carry an XP...

I've had a few close encounters with gliders too lately.

Not a lot one can do....

IO540,

Yes, you're quite right about being dependent on other aircraft having transponders. Actually, not just having them but turning them on - I pass quite a few PA28s and the like which presumably have transponders fitted but don't show up on screen .

This is one of my main worries about GA TCAS; it has the potential to lull you into a false sense of security in that it's easy to start to assume that it'll tell you about everything that's out there. The fact that it tells you about so much traffic you wouldn't otherwise have been aware of only reinforces this impression, but it's a potentially dangerous one.

Because I fly microlights as well I'm quite aware that the majority of my lightweight friends don't have a transponder and therefore won't show up, but even so it is very easy to start to rely on that nice colourful TCAS screen.

Who has transponders ... ?
 

Some time ago I heard a conversation between a control tower and a passing balloon ... the balloon asked what he should squawk, and the controller was having great difficulty replying "not to bother because I don't have SSR, and anyway I can see you out the window" without collapsing with the giggles!

That was a while back. Is it usual for balloons to carry transponders these days?

I don't know about is it usual, but if EASA has its way it will become so within a year or two. The compulsory fitment and use of Mode S transponders for all (sic) flying machines is one that is currently exercising the collective minds of the representative bodies. Personally I thought it was like requiring pushbikes to be fitted with tachographs, but having seen this thread I'm not quite so sure.

What happened to the pilots who think look out is the answer to mid air avoidance?

None have appeared on the thread yet, but they will.

Sorry bluskis, didn't see you there.

VFR - just past Aston Down is Nympsfield (another popular gliding site). This week they were hosting a large competition event and, at times, the gliders were so thick you couldn't count them! On wednesday they were flying a 200km course (out and return) so they were spread over a wide area of countryside.......

bluskis,

Pointing out that the Mk I eyeball is unfortunately not a 100% effective means of avoiding collisions is not the same as suggesting that it's not the best option that most of us have most of the time.

Don't expect just to see gliders over a gliding site. During a typical 9 day competition there will be over 60 gliders flying tasks from 150km to over 500kms,racing round. From 1 glider in a thermal to over 30 in a gaggle, cruising from 60kts to 100kts. All comp pilots wear parachutes & when thermaling in a gaggle the risk of collision is HIGH.

Fly Sim

Can't argue with that, but it is better if we don't rely on them 100% and try and use other resources.

I wonder how much look out a glider pilot does when he is concentrating on the rate of climb indicator and circling at the same time.

Having been involved in the open national comps at Lasham a couple of weeks ago where we were set tasks over 650kms the areas of countryside covered with bloody hard to see gliders can be pretty staggering.
As to the level of lookout kept by glider drivers, it's actually very high, especially in thermals.
When you are in a gaggle with up to 40 other gliders all spinning in their own variations of a circle and vertical separation in the tens of feet between you and the next 750kg of plastic doing 55kts self preservation dictates that you activley participate in the 3D version of "asteroids" you find yourself in.
The VSI main output is audio, the analouge display is there really just for decoration.
Nav in a staright line is handled pretty much automatically by computers these days so that doesn't take much "head down" to follow.
We are _always_ looking for other gliders / ac you literally have a sore neck after a 6-8 hour comp flight.

Do have to agree that we are _very_ difficult to see from any distance away.

Don't know how to improve that situation though.

"Paint the f*****g things black instead of white" has been suggested. (Not having seen a black glider myself I can't personally judge whether this would work for me.)

Perhaps gliders could be equipped with a capacitance driven high intensity flash light, energised from an airflow driven rotor.

Light doesn't take much energy to produce, so should it not inhibit performance noticebly, and light flashes are very attention seeking.

Alternatively there are those joggy red flashy lamps cyclists sometimes use on a rainy November night.

BS,

Other than at night how often is the flash of an ACL the first thing you see from an aircraft?

Flew near Cardington last week and the blimp was out playing.

It has a flashing beacon on its rear. I could just make it out against the wopping big background which was the blimp itself.

FD

I do agree that I have never seen a flashing beacon before, or even noticed it after, I have spotted another light aircraft in daylight.

However there are times when a glider is well nigh invisible and any high intensity light may help.

We put on landing lights in daylight approaches, and magic, we can be seen in the haze. I sometimes put on my landing light in poor viz when in choke points where there may be oncoming traffic.

"Paint the f*****g things black instead of white" has been suggested. (Not having seen a black glider myself I can't personally judge whether this would work for me.)

As there are a couple of black gliders out there, that obviously doesn't work either :D

as for turbine powered lights, ahem.
People don't spend £120,000 on a sailplane to go and stick drag inducing devices on the outside of them.

There is no doubt whatsoever that one could make a low power transponder, battery powered and weighing under 2-3kg in total, which would do the job at short range (few miles) as far as TAC/TCAS systems go. Cost? Perhaps under £1000 in volume.

Then you've got the ever so slight problem of fitting the mostly-decrepit GA fleet with the other half of the system. Present cost is about £20k; this would come down but almost nobody would spend the money, and there are enough people who believe it is their god given right to not have a transponder, so nothing is ever going to happen.

That's why I would not spend money on TAS; if you are higher up there isn't normally much traffic there (other than IFR traffic playing by the rules) and lower down there are so many undetectable planes that it wouldn't make much difference.

Painting a glider black : :{ the UV absorbtion and the Temp of the gelcoat might alter the life of our precious machines !
If I remember the the USAF has a/c painted black : SR71, B2, F117, etc.. not to be seen....

The strobe light does not work on bright sunshine = 90% of the time when gliders fly , ( except possibly in the UK ;) )

The low cost / low weight / low consumption SSR for gliders exists already : Becker has one with mode C encoder and antenna for 3000 euros. But it is not mandatory (YET)

No need for TCAS at 50.000 Euros for GA, ADS-B displays will do the trick for 3 or 4.000 euros when they will be available ,

Best trick at the moment : put orange reflective tapes around the nose, wings and the end fuselage, this does not affect drag, and cost very little. In many clubs in the Alps this is mandatory.

The BEST way however still remain to LOOK OUTSIDE all the time ...:E

IO540

On the TCAS subject, I do most of my flying in the 2500-4000'
range and find Skywatch valuable.

While there are some non-transponder equiped aircraft
about, there are less than you would think.

The main advantage is making the encounter with other
aircraft less of a surprise and alterting you to how many
potential contacts you never saw previously.

I would say that on typical 1 hour trips it has reduced
the number of close encounters by a factor of 80-90%.

-- Andrew

Andrew, What is the current ( approx ) price of a Skywatch incl installation ?

for those wanting to have a look at the machine :
http://www.goodrichavionics.com/docs..._Avoidance.pdf

looks very good but looks expensive as well .:hmm:

To largely repeat what I have posted elsewhere:

Most gliders are precluded from other than white finish because raised temperature from heat absorption weakens composite material.

I have asked the question about strobes for gliders in the past, and been told that they do not significantly aid visibility. Furthermore there are no approved modifications to fit them. While not impossible to overcome, that is a considerable hurdle for a fitment of dubious benefit.

The glint from wings is a huge signal compared with a strobe, though only effective when a glider is turning, and even that I find limited to a range of 1-2 miles.

High visibility fluorescent paint has been tried in controlled tests and found not to help - surprising, but true.

Batteries are a big problem for many - there is no room for more, and the weight limitation is already reached, on some, perhaps many, gliders. Even the 2-3 kg quoted above would put me over the limit in my glider. I also have no panel space, nor space elsewhere in the cockpit, for an extra box or two.

Could those who think solar power is the answer please look up what output you can get from a panel that would fit on a glider, and compare it with the power needed to drive a strobe or a transponder.

Personally I would welcome a workable solution. So far I am not convinced that there is one. I have no more wish to have anyone else fly into me from a blind spot than he/she has to do it. Statistically, however, GA/glider collisions are about the rarest form of accident. I can only recall two in over 30 years, and one of those was tug/glider in the vicinity of their home gliding site. Both power pilots and glider pilots have found far more prevalent ways of killing themselves.

Chris N

And of course the white finish issue is equally applicable to powered aircraft constructed of the same materials. Anyone seen a black Europa, Jabiru, Sky Arrow, Polaris, Grob..........?

The main point at which it is difficult to see a glider is when it's pointing at you or away from you at the same height because of their low frontal area. However gliders tend not to be doing that for long so a visual scan that looks at the same piece of sky twice with a few seconds between is very likely to pick it up as it turns. If it wan't easily visible on the first sweep it is probably a lot easier to see on the second.

Mike

Re bluskis query on how glider pilots watch their rate of climb indicator and keep a good lookout at the same time.

It's done by having an audio output from the rate of climb indicator (variometer) which makes happy noises when you're going up and derisive noises when you're going down.

So they don't have to watch it, they listen to it.

And the sound can be heard, because there ain't no noisy lump hanging on the front of the aircraft.

And personally I fly a red white and blue glider, which as it's made out of wood, doesn't go floppy in the sun.

I'll chuck my twopenneth in! I'm a PAraglider pilot - hill launch oversized kite. I can't talk for the sailplane fraternity, but I can offer a few pointers from our lot. The majority of soaring sites are marked on airmaps, some aren't however & that can be a problem. If we fly around military areas, Wales, Peaks etc, we NOTAM the freephone RAF no during the week. The vast majority of hang & paraglider pilots will fly belwo 1000 agl all day, in any event, no one will be above cloudbase, except in rare wave conditions & then only the brave!

Long xc's are commonplace - 100ks regularly gets flown from my home sites & pilots will be anywhere from 50agl to cloudbase on those days, but they will be downwind of the hill they began from, so possibly worth bearing in mind. The xc season in the UK runs from spring to autumn & the classic days I.e. those likely to bring you into contention are post frontal light northerlys, high lapse rates, plenty of instability & cumulus clouds - them's the signs.

Having said all that, the vast majority of pilots are punters (like me) who do not want to bring down the wrath of the CAA on their heads & follow all the rules - it just takes a couple of morons to ruin it for us - currently, the CAA are making noises about compulsory xponders for us lot, following an airprox near bournemouth airport - we don't want them, so most of us behave. I spose we're a cross section of people like you'd find anywhere. Hope that helps.

Modern gliders, as was said before, pretty much have to be white to protect the composite structure. Same thing as with the airlines being somewhat limited in their choice of color on the composite parts on the big iron (or is it “big plastic&iron” these days?).

A ram air turbine on a glider? Some algebraic exercise will tell you that a 300 kg glider doing 110 km/h with a 40 glide ratio will have a total drag of about 7.5 kgs. Not more. We add mylar strips to canopies, rudders and so on to prevent drag from air leakage. Competition pilots polish their aircraft to increase performance. Drag is The Enemy.

That amounts to an energy conversion rate of about 2250 W. Say that you create a ram air turbine assembly to power a strobe with an efficiency of 50%. That’s a wild assumption, and I think it will be rather difficult as you will have to count in the total drag of the installation in the efficiency calculations. If the strobe needs, well, 100W, making full use of those capacitors (how big and heavy will they be?) suggested to produce only very short flashes? You’ll have to use 200 W of potential energy. To get the energy conversion up, the GR will go down to under 37 and the sink rate will increase from .76 to .83 m/s. A GR 50 glider would go down to GR 45. In gliding, that is significant. And I think the figures for efficiency and power consumption are optimistic, although I’ll happily redo the calculations with more exact figures if someone can provide them.

The way transponders work pretty much dictate that they are very energy consuming. They’re emitting a lot of radiation energy every interrogation. Not something you’ll want to run off batteries for a day as you’ll have to lug around a significant amount of batteries! Further, they’re comparatively heavy, bulky and expensive. I’ll have a look around for that Becker thingy - it’ll be interesting to see how they’ve solved it.

ADS-B and VDL mode 4 is the way to go. Installations are being flight tested.

Fluorescent panels are indeed often required in mountain flying. Not since they help visibility in the air, to the best of my understanding, but rather to aid search and rescue should the worst happen.

Cheers,
Fred

There is a thread on a (mainly American) soaring webite - "ras" - on transponders. They are fitted to some gliders in the USA in regions where flights are habitually near airline routes. One recent posting included reference to an 18AH battery, which is far larger than any I have seen (or seen room for) in any UK-based gliders. It refers to a motor glider (Schleicher ASW 26E) with a foldaway engine having doors on top of the fuselage (behind the cockpit and wings) and a retractable undercarriage. I don't know how the modifications for installing the transponder would get approved in the UK, though I expect it could be done on the same model in this country, at a cost, if the CAA would permit it:

"I have the 175 watt Becker with ACK A30 encoder in my 26E. No clue how long
the ship's 18 AH avionics battery would power it as there's solar panels on
the engine bay doors helping out. If I turned off WinPilot I could probably
sell power to the utility. In any case, I suspect it'll last way longer than
me. AFAIK the 250 watt Becker is only recommended if you spend a lot of time
in the upper flight levels.

"Antenna is mounted on the belly just aft of the gear door. The thinking is
to get the antenna as far as possible, within reason, away from the pilot's
body. No sense testing the long term effects of high frequency radiation."

This sort of thing certainly could not be done at present on the glider I normally fly, nor on many others, because of weight and space limitations.

Chris N.

Further to previous postings about conspicuity of gliders, I have just seen on the (mainly American) soaring website - "ras" some postings on strobes.

One quote: " . . . the distance at which the
strobe was noticeable during the day was so relatively short that there
was minimal benefit to the installation"

Another: "The other issue is power consumption. The Whelan Cometflash strobes in my
Mooney draw about 7 amps at 12 volts. They're bright, perhaps even bright
enough to be effective in daylight. On the other hand, the strobes in my
Stemma draw only about 2 amps . . . nowhere near as bright, they would be
next to useless in daylight."

I believe most gliders have a 7AH battery, so the Mooney-type strobe would drain it in an hour, even without the other glider instruments taking any current. In practice a separate battery would be needed for the instruments etc. Some gliders have provision for two batteries, and/or a 12AH capacity, but even so there is little hope that present strobe technology would be practicable and helpful.

I wish there were an effective solution, but it seems that there is none yet.

Chris N.

I have never seen a glider whilst flying an airplane (of course, that doesn't mean that they're not out there, just that I haven't spotted them). But I have seen quite a few airplanes whilst flying gliders. Almost without exception, they have been far below me.

My advice for glider avoidance is to fly as low as is reasonably safe. Generally speaking, if you are less than 3000' agl you won't run into much glider traffic.

MLS-12D

P.S. I appreciate that this advice may be impractical for Boeings and Airbuses, but I don't consider them 'real airplanes' anyway! ;)

MLS-12D

I have never seen a glider whilst flying an airplane

I was just about to ask which universe you live in; then noticed you are in Canada :O

I see countless gliders, everywhere up to say FL060.

Flying low is the worst advice for GA traffic; most of it is already below 2000ft agl and most military low flying is done there also. The higer one is, the less traffic there is, the better service one gets from radar units, etc...

Surely there is an answer to the conspicuosity (is the such a word?) problem - sunlight.

It must be possible to make a honeycomb of modified cube corner reflectors that, when formed in the shape of a fuselage panel, would give a useful 'glint' in most orientations and lighting conditions, perhaps even when thermalling under clouds.

To do this, the reflectors would reflect through angles other than the 90 deg used in cat's eyes. I wonder if this has been tried? It's not the steady intensity of reflection that's needed - just the momentary flash of a single reflector aligning the sun and the observer's eye. The continual manoeuvering of the glider would do the rest.

Just an idea.

Hello Io540!You may well be right, however I stand by my advice that you can miss virtually all glider traffic by flying low. I don't know any soaring pilots who voluntarily fly below 2000' agl: "get high and stay high" is usually the nature of the game.

Cheers,

MLS-12D

P.S. Sorry to hear that military traffic is a problem for you. Here, essentially all fast jet low-level tactical flying is confined to Alberta (Cold Lake Air Weapons Range) and Labrador (Goose Bay), both of which are bigger than the entire UK. Miles upon miles of empty tundra, far from civilization: just the place for the boys to do their Mach 1 stuff at 50'. :ooh:

I've seen gliders well below 2000' regularly around here. Quite likely because airspace restrictions mean they can't get much higher....

FFF
--------------

FFF

Given they have no transponders, nobody would notice would they :O