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-   -   Thoughts on reducing risk of mid-airs. (https://www.pprune.org/private-flying/377743-thoughts-reducing-risk-mid-airs.html)

Lister Noble 15th June 2009 17:10

Scanning
 
liam,scanning for other aircraft is covered in Air Pilot Manual 6-Human factors and pilot performance.
This is of utmost importance,I would ask your instructor to demonstrate the method,as has already been suggested.
It was drilled into me that looking all around really well, before a turn, is paramount.
Especially the area you are turning into.
And of course the circuit.
Lister:)

bookworm 15th June 2009 17:44


In the example given, I think that "12 o'clock" and "opposite direction" are enough of a clue that a turn in either direction would be a better option than remaing on the current heading.
Unfortunately, that's not the case. You're doing 150 kt. An aircraft reported in your 12 o'clock, "opposite direction", at 5 miles may be passing safely down your right side by a mile. A right turn of 30 degrees puts you perfectly on to a collision course with him if he's doing the same speed as you. More than 30 degrees then? What if he's just a little faster than you? :(

If the controller simply said "turn left to increase separation" or even described the encounter as "left-to-right" which, in terms of relative bearing, it is, the action to take is obvious -- you turn to the left.

TrafficPilot 15th June 2009 18:12


A large % of PPL pilots fly low; 1000-2000ft. Presumably the view is better.
Not down here for me in the South/South East. It's because the airspace squeezes us into a tight band of low altitude class G.

TrafficPilot

vihai 15th June 2009 18:46


Originally Posted by liam548 (Post 4998858)
surely the paint technology exists so you can have coloured paint that does not absorb heat??

The very purpose of paint is to absorb light. It reflects the desired colors and absorbs all the other visible light.

You would need a "paint" that converts light into something else. Photovoltaic cells are the only device I know to exist.

Maybe some new nanotechnology based on quantum dots will be able to change light frequency and have paints that appear to be unnaturally brighter (and cool).

Bye,

gpn01 15th June 2009 18:47


Originally Posted by bookworm (Post 4999183)
Unfortunately, that's not the case. You're doing 150 kt. An aircraft reported in your 12 o'clock, "opposite direction", at 5 miles may be passing safely down your right side by a mile. A right turn of 30 degrees puts you perfectly on to a collision course with him if he's doing the same speed as you. More than 30 degrees then? What if he's just a little faster than you? :(

If the controller simply said "turn left to increase separation" or even described the encounter as "left-to-right" which, in terms of relative bearing, it is, the action to take is obvious -- you turn to the left.

If there was opposite direction traffic, same height, I'd be thinking of turning more than just 30 degrees. With a combined closing speed of 300kts you have 60 seconds or less to take avoiding action. I think I'd take the hint from the controller who's trying to help, rather than elect to plough straight on and play the odds of just how recipricol the "traffic, opposite heading" call was. You're right that it would be better if the controller could drop a hint, e.g. "suggest turn right for avoiding action" but I'm not sure if they're mandated to do that or not.

[later edited because I'd missed the bl**dy obvious]....should have added that climbing or descending, depending upon airspace constraints, would also be an option.

fireflybob 15th June 2009 18:52

In the days before radio they HAD to lookout and were much more disciplined about (for example) circuit joining procedures. Ok there is a larger diversity of traffic around now but in many ways not a lot has changed if you are operating VFR.

Whilst not being a luddite I think the overuse of services such as Radar/FIS etc can lull pilots into a false sense of security. There are also more potential distractions such as the GPS, even changing frequency means head in the cockpit during which time another a/c can be filling the windscreen.

I know it's a generalisation (and I speak as one who has spent most of his flying career in civil aviation with a spell as a military flying instructor) but in the military there is much more emphasis on LOOKOUT since apart from anything else if you don't spot the enemy first he might shoot you down. So it's surprising to see that recent midairs have involved military operated a/c.

When teaching lookout on early details with students I tell them that lookout is an acquired skill and, at this stage, just because they cannot see an a/c doesn't mean there isn't one out there. Also don't get preoccupied with the one you can see - keep scanning!!

Finally, make sure the windscreen is clear - in summer a screen full of squashed flies can mask the target which might spoil your day!

atceng 15th June 2009 18:54

I'm just getting into this aviation,and unlike any other discipline I've been involved in none of the 'Rules' ever seem to be appropriate to the situation and pilots seem to go out of their way to do the opposite.

UKANO collision avoidance in the air Rule 8,when approaching head on,each must turn to the right.

Given the scenario of direct head on confirmed by range closing,bearing not changing, why should anyone contemplate a left turn,as bookworm has suggested ? No, seriously, tell me, there is probably a good reason which my superficial approach has missed.!

In the last 6 months albeit flying in an uncongested part of the uk (not saying where as it would then become the most congested):\ I have never seen the 'strobe' of other 'craft.
This bit of equipment needs serious re-engineering to become effective. In other environments strobes are used for collision avoidance,drawing attention to alarm states etc. very effectively,but the aviation variety needs an order of magnitude upgrade to be useful. Perhaps if feasible this would be a cheap, simple, universally applicable and effective way of improving see and be seen.

atceng

fireflybob 15th June 2009 19:05


Given the scenario of direct head on confirmed by range closing,bearing not changing, why should anyone contemplate a left turn,as bookworm has suggested ? No, seriously, tell me, there is probably a good reason which my superficial approach has missed.!
Notwithstanding Rules of the Air rights of way - you are entitled to do anything to avoid immediate danger - just because you have seen him doesn't mean he has seen you!

Also emergency (ie avoidance) turns are not in the PPL syllabus whereas the military do teach them to students. I think ETs should be in the PPL syllabus - there was a thread on Pprune a while ago on this topic.

bjornhall 15th June 2009 19:10


Given the scenario of direct head on confirmed by range closing,bearing not changing, why should anyone contemplate a left turn,as bookworm has suggested ?
Because that was not the scenario. The key point is that "12 o'clock" is not the same as "direct head on". The bearing can change quite a bit and still be "12 o'clock".

bookworm 15th June 2009 19:14


Given the scenario of direct head on confirmed by range closing,bearing not changing, why should anyone contemplate a left turn,as bookworm has suggested ? No, seriously, tell me, there is probably a good reason which my superficial approach has missed.!
That was most definitely not the scenario I described. If you could see the other aircraft, you'd see the bearing was steadily increasing. If you simply assume, based on the controller's "12 o'clock opposite direction" limited information, that the other aircraft is on a collision course, the right turn that you suggest would take you into conflict with the other aircraft.

IO540 15th June 2009 19:18

The reason why a "Traffic Service" ATCO does not give avoidance vectors is because he is not allowed to. Rules are rules. Safety doesn't come into it.

bjornhall 15th June 2009 19:18


Less time 'eyes-in' looking at gucci GPS moving maps.

More time 'eyes-out' looking for threats.

Less time eyes in peering at charts and trying to compare that with ground features

More time eyes out looking for threats instead of peering at the ground.
Agreed!:ok:
It makes little sense, in my view, to require a good lookout to be kept at all times, while at the same time teaching navigation methods that appear to maximise the time spent on navigation! Whether it is toying with a GPS with ten million features, or trying to match every church, barn and tree with the map, it just takes too long and is not necessary. Navigation is about getting accurately from A to B, isn't it? So why aren't students taught how to navigate with the minimum possible effort to accomplish that task?

whiterock 15th June 2009 19:27

FLARM
 
I posted the following on the original thread about two aircraft down.

I think it is worthy as a contribution on this thread also.

A mid-air collision is a dreadful event which any pilot would want to avoid.

However, the solution for GA is not as simple as putting a gadget on the panel
to do the looking for us.

The FLARM is a good device for glider pilots in the environment they fly. But only any good if all the other aircraft likely to be met in the air are likewise equippped.

I have installed a FLARM system to a GA aircraft engaged in glider towing. When fitted to a powered aircraft it needs to be heard over the noise of the engine and radio. It will therefore need to be properly powered and connected to the aircraft's audio system. This will involve a modification to the aircraft which will need CAA approval (for a fee) and installation (for a fee).

To connect the FLARM to the audio you will also need a FLOICE unit, which is a voice-intercom interface.

Remember that a glider pilot usually has a bubble canopy with excellent vision capabilities so in the event that a FLARM warning is given (visible and audible) the pilot can quickly look for the conflict and take avoiding action. I believe the range of the FLARM is such that a warning is given 15-20 seconds before possible conflict.

Most GA aircraft do not have such good all-round vision and as such, a FLARM alert may not give the pilot time to digest the audible and visible information, look out to verify, given the many blind spots inherent in GA aircraft and take the correct avoiding action.

I am of the firm belief, as a PPL of many years, that the basis of collision avoidance in the FIR can only be a good scanning technique.

As is so often the case in these events, it is better to wait for the AAIB report before deciding a course of action based on where the perceived problem was in the case of the event in question.

soay 15th June 2009 19:36


Originally Posted by fireflybob
in the military there is much more emphasis on LOOKOUT since apart from anything else if you don't spot the enemy first he might shoot you down. So it's surprising to see that recent midairs have involved military operated a/c.

Which reinforces my feeling that the Mk 1 eyeball doesn't cut it. You just need to fly in a TCAS equipped aircraft to realise how much "invisible" (but transponding) traffic there is out there on a clear day. Get in the haze under an inversion layer and you've got to hope that the big sky theory works! I'd rather have ADS-B.

atceng 15th June 2009 21:02

bjornhall, and others advising arbitrary avoiding action (new acronym AAA) the opposite to the rules,you make my case perfectly.

If a consistent heading of 12 oclock even allowing 30deg isn't developing into a direct head on when the bearing doesn't change from 10 miles,5 miles,3 miles,1 mile,then I hope never to be flying in the same airspace.

Draw it out and see! Then work out what happens if a right turn is made and the other 'craft does nothing,'cos he hasn't seen you or turns right,'cos she has,(ignoring the possibility that its old bjornhall who's going to turn left).

Work out the permutations and you will see that you are certain to avoid by prompt rule-following action. If both 'craft follow the rules even better.
If one 'craft does the opposite to the rule then wham, another statistic.

Lets all just follow the rules,there isn't time to argue even with yourself.

atceng

bjornhall 15th June 2009 21:24

atceng, the thing you are missing is that ATC traffic information is not accurate and precise enough to use for maneuvering. That requires vectoring. Traffic information is a great help since it tells you where to scan for traffic. Following the rules for collision avoidance comes after you have acquired the traffic. If you are drawing geometry in the cockpit you have your priorities all wrong.

But I also think you are concerning yourself with the wrong issue. Midairs do not happen because pilots fail to follow the rules regarding maneuvering to avoid collisions. Midairs happen because pilots fail to see each other. So rather than get distracted by this unimportant tangent, let's focus on the real issue: How to spot other traffic.

funfly 15th June 2009 21:28

The RAF did some research a few years ago and came up with black being the best colour for air to air visibility, hence they now paint all of their training aircraft black except for the tips etc. My last aircraft was Fibreglass and white but it did have a couple of black areas ,wing walkways' however these got extremely hot and I would hate to have had the whole aircraft that colour. On a previous white aircraft I covered the leading edges of the wings with silver reflective tape and this was extremely good for visibility. (but I don't know if I should have put this in as a mod?)
In practice there are very few mid-airs however I have a policy of never planning a flight from overhead the field and flying at altitude just higher or just lower than the thousand feet mark. pilots often take a pride in being at the exact height - often a multiple of a thousand foot! so stay out of that zone.
In GA flying KEEP AWAY from glider sites and parachute sites.
My penneth.

mary meagher 15th June 2009 21:34

when meeting another aircraft head on .......
 
Both should turn right, right? Well, that's the rule, isn't it?

Twice while tugging up a glider, this didn't work.

Junior Nationals Gliding Comp a few years back at Weston on the Green, pulling up a 19 with a Navy pilot, noticed a twin hauling a.... out of Kidlington, so I turned right to avoid him (of course towing a glider, I theoretically had right of way, right? )

He turned left.

I had nothing left to do but dive, with the Navy 19 still hanging on for dear life. Which is the right action for the glider on tow; we present one target (if a rather extended one) rather than two disparate targets. It was nice that he backed up my story when I returned to ask the director to please let Kidlington know what we were doing and where.

The other occasion a very experienced glider pilot was behind me and warned me of traffic; I hadn't seen it (nose high, you know) and began to turn right, and he said very very emphatically "TURN LEFT NOW!!!!" So I
did, and it was so near that if he hadn't directed that avoidance, I wouldn't have been here to file the airprox. The equipment on the glider exactly pinpointed the time and place, so we were able to trace the opposition.

That pilot had thought it would be sensible to dive under the combination.
Not really; if we hadn't seen him and diverged just then, it would have been
normal for the tug to descend.

I say again, LOOKOUT, LOOKOUT, LOOKOUT. Please.

David Roberts 15th June 2009 22:39

Sunday was the best gliding day so far this year. In terms of weather. Obviously and very sadly not for those involved in the mid air near Abingdon. I would guess that a large proportion of the UK glider fleet (c. 2500) was airborne on Sunday and a fair proportion of them in the southern England area OCAS. See Daily Scores for those that logged their cross country flights - and that is by no means all who did cross countries on Sunday. And look at the distances flown - sans moteur.

I suspect there were a great number of GA aeroplanes also in the height band 1000 - 5000 ft AGL, below cloud base.

What this shows is that Sunday was the equivalent in road traffic terms of a sunny bank holiday weekend on the M5 to Devon - crowded. So statistically one would be more likely to encounter more than the odd aircraft en route.

Now even the proponents of using any ground based advisory radio or radar service in Class G will quickly realise that with (a) the speed at which the high volume of airborne traffic is moving (b) the delay factors contacting and getting a response from the ground based third party (c) the overload factors on a ground based person (d) the fact that gliders do not follow a straight line necessarily and are constantly ascending / descending, then it is impossible to have a fool proof ground based human third party intervention system to keep us all apart.

So the quickest means to do so is constant lookout. Backed up by Flarm or something similar. I have flown with Flarm for 4 years now - mostly in the French Alps - and I can say with confidence that it reduces risk but of course will never eliminate it. The price is worth the extra mitigation.

As to conspicuity, there have been various experiments conducted over the last few years with regard to making white gliders more visible. None have proved conclusive of a better scheme, other than the RAF black (which of course we can't paint our gelcoat gliders with, for reasons already given in this thread). Even orange dayglo strips and markings on the wings do not work that well. In fact my French colleagues - with many '000s of hours mountain flying - say that often these markings break up the profile of a glider against the mountain / snow background, with the result that the aircraft becomes a smaller profile. This I experienced first hand last month high in the Alps when the Flarm gave a 'three reds' alert. Neither my co-pilot nor I could see another glider until it passed close in front and underneath us as we thermalled. And the other glider was covered in dayglo strips. BTW my eye test last week was A1....I write as someone with 40 years' gliding, 2700 hours and some power flying. I intend to do a lot more as well, looking out and hoping I see everything. But I won't rely upon third party sources on the ground for this.

liam548 16th June 2009 05:48


Originally Posted by Lister Noble (Post 4999113)
liam,scanning for other aircraft is covered in Air Pilot Manual 6-Human factors and pilot performance.
This is of utmost importance,I would ask your instructor to demonstrate the method,as has already been suggested.
It was drilled into me that looking all around really well, before a turn, is paramount.
Especially the area you are turning into.
And of course the circuit.
Lister:)

thats my last written exam left to do after aero tech. I am aware of clearing turns and looking before turning. I was under the impression reading this that there is a specific scan technique when flying straight and level.
At the minute I split the view into different parts and scan each section at a time, middle, fore and back. I will ask instructor though next lesson.


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