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Midair Collision Near Waddesdon

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Midair Collision Near Waddesdon

Old 18th Nov 2017, 08:59
  #101 (permalink)  
Join Date: Jan 1999
Location: north of barlu
Posts: 6,201

Why would any one fit a mode C transponder these days when mode S is mandated almost everywhere ?

I have seen some of the certified traffic systems and most of these are expensive and heavy so only suitable for the upper end of the single engine market.

The traffic system that seems to meet the lower end of the market is POWER FLARM, the cost of the system is low ( about £2K ) and the system weight is about 0.5Lb. It will detect and give position of Mode S , ADS-B & FLARM targets and proximity to mode C targets. The system is Garmin Compatable so those with Garmin moving map displays can see the traffic. This is the traffic system road I am going down with the display going onto a G500.

This system should only be seen as a back up for the Mk 1 eyeball but with my main collision threat coming from gliders ( that are very hard to see ) and with the FLARM take up within the gliding community being so high the POWER FLARM system represents a considerable safety improvement for not much cash. I know that installation in a wooden Aircraft such as mine is simple but even with the issue external antenna fitting FLARM to metal Aircraft the cost is reasonable .

This can ( at last ) be done under EASA CS-STAN ( as can mode S retrofit ) so the paperwork costs are very low.
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Old 18th Nov 2017, 09:00
  #102 (permalink)  

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Originally Posted by russian roulette View Post
A and C

Agree with TCAS - that can be a personal choice. No one is advocating TCAS for all, but Mode C for all is inexpensive and lightweight.

And, yes of course there can be a collision if the RA is not followed. You could say the same about a stick shaker - people have pulled instead of pushed !
Many smaller aircraft operated in Class G already have ACAS/TCAS I or TAS but that version only gives TA, not RA. I've been using it for almost 20 years and would feel very vulnerable now without it. It has to be used in context, the most relevant aircraft might not appear on it for reasons already known and so it must be used to assist lookout, never to replace it. It works very well as long as it's limitations are understood. It's proved to me many times that lookout alone is very often inadequate, due to human limitations. I've lost count of the number of occasions when other pilots had a clear obligation under the rules of the air to take necessary avoiding action from our aircraft, but completely failed to do so because they obviously never saw it. So we are always prepared to take action instead. Thankfully TCAS gives good advance warning so we can (and very often do) avoid a conflicting flight path by taking early action.

I posted on this forum very many years ago to explain that the full use of the transponder with mode c where fitted was a great asset to safety because a TCAS equipped aircraft could "see" other aircraft well beyond the range of human eyesight. I got heavily criticised by some who claimed I was using it as an excuse not to look out and even by some who considered the use of a transponder a breach of their human right to remain anonymous in flight!

Last edited by ShyTorque; 18th Nov 2017 at 16:21. Reason: factual error correction!
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Old 18th Nov 2017, 09:00
  #103 (permalink)  
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I have only flown with TCAS for the last 3 years and even with the odd false alert or wrong sector indication, it is far, far better than just relying on the Mk1 eyeball.

The wannabe (or ex) fighter pilots need to remember that not all Mk 1 eyeballs are equal and a great may GA pilots are of more mature years - are spectacle wearers (possibly bi or tri focal) or just have less than perfect eyesight. Add in creaky or arthritic necks and you have great potential for degraded lookout.

There is no reason that all flying machines shouldn't be equipped with a transponder at the very least - you wouldn't go out driving at night without your headlights on. Remember it is SEE and BE SEEN.

Allow those with TCAS to see you even if you don't have it fitted yourself.

The system I use is a simple display but it has an audio alert - no RAs or anything, just distance and clock code - but it has helped me see aircraft far earlier than I could have noticed/identified them with the naked eye.

Technology might not be the absolute solution but it goes a bloody long way towards it.
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Old 18th Nov 2017, 09:05
  #104 (permalink)  
Join Date: Dec 2007
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Sincerest condolences to all involved. I cannot imagine what HS must be going through right now.

I have known the HS team since the mid-90's though haven't been in touch for a few months and no longer work in the industry.

A very sad day for aviation.


Last edited by heli14; 18th Nov 2017 at 10:20. Reason: PM received, thanks
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Old 18th Nov 2017, 09:07
  #105 (permalink)  
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Originally Posted by fireflybob View Post
One thing that has occurred to me recently is that modern avionics seem to (potentially) require more head in the cockpit (unless managed and taught appropriately).

In the olden days when we only had 180 channels on VHF (100 kHz spacing) one could change from say 119.5 to 126.1 in a couple of seconds. Now especially with the smaller electronic displays it takes longer and more fiddling to change from say 126.225 to 134.175. I teach to change the whole MHz first and then have a lookout before setting the decimals. Same applies when changing ILS/VOR frequencies where with sets like the GNS430 I now have to find and press a changeover button before changing frequency. One of the latest mode S transponders require one to alter and then enter each digit separately and sometimes the transponders are sited on the other side of the cockpit. At one level this might sound trivial but it isn't in the sense that it encourages pilots to be more head in the cockpit. Add in the mix of other devices which many pilots use now and we have even more ingredients for not looking out adequately.

In fact you're much more likely to have a close encounter or a mid air in the circuit area than the open FIR notwithstanding choke points. Historically there have even been collisions worldwide within controlled airspace and I believe in the USA some time ago the statistics showed highest risk of midair was in airspace with mixed VFR/IFR traffic close to an airport which is equipped with radar.

Whilst I'm not a luddite I don't think this risk will be entirely solved by requiring all aircraft to have transponders with TCAS and/or be in receipt of an ATC service.
Almost totally agree, Bob and when I fly in that area ( out of WW) I do at least ask and receive a basic radar service from Benson who are most cooperative. That said, now that electronics are so light and cheap, a TCAS or FLARM system could, at least, significantly reduce the risk.

Some years of flying in a military training environment, as a QFI and student, with lots of JPs flying in the high density training area really hammered home to me the value of a diligent and continuous lookout.

Still, a very sad, tragic, accident.
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Old 18th Nov 2017, 09:16
  #106 (permalink)  
Join Date: Jan 1999
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As a long term ( former ) resident of WAP and a former employee of AAA Ltd I too am shocked and saddened by the news that people who I have worked alongside have perished.

As of this moment I donít know exactly who has died and being out of the UK dont want to further distress those at HS & AAA by making enquiries on the phone.

As of yet I donít know who to direct my condolences to , I am sure this will become apparent in the fullness of time, meanwhile I am happy to discuss the technical issues surrounding traffic detection equipment but not anything to do with this tragic accident.
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Old 18th Nov 2017, 09:22
  #107 (permalink)  
Join Date: Nov 2017
Location: Bristol
Posts: 164
As quoted if true............but rotor while flying on 1000 ft in steady course
had no chance to see above&behind and plank last data was:
2,700 ft Vertical Speed -1,536 fpm.

A descent of 1536 fpm seems very high for a C152, and comenced below a height where you would not generally enter a spin or spiral dive. Despite which you would make clearing turns first.

A glide, approach, or normal decent would be more likely to be 500, 600 fpm in a C152, sideslip slightly higher.
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Old 18th Nov 2017, 09:30
  #108 (permalink)  
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...now that electronics are so light and cheap, a TCAS or FLARM system could, at least, significantly reduce the risk.
Absolutely. Electronic conspicuity is the name of the game if we want to improve the accident statistics.

Yes, lookout is vital but no-one can see around their aircraft 100% of the time in all directions. I use TCAS at work but it doesnít really fit with typical GA flight profiles.

I have FLARM, which will alert me to traffic that it perceives as a threat, getting more insistent as the time to collision reduces. It doesnít tell me what to do but where I should look. If I canít see whatever is causing the warning, I know I need to change height and/or heading to deconflict.

A properly installed and set up EC system should have much less in the way of blindspots than humans have when seated in light aircraft. It is a complement to lookout, not a replacement but in todayís crowded skies and in areas where traffic is funnelled under and/or between airspace restriction, I think it is indispensable.
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Old 18th Nov 2017, 09:38
  #109 (permalink)  
Join Date: Jul 2005
Location: In the South !
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Sadly I watched this accident on radar . . . . both Mode S equipped squawking A and C. Any form of ACAS would have helped. Condolences to all those touched by this tragic but avoidable event.

Having spent half a decade watching the maggots within 15nm of WCO on a good flying day I can tell you that's the last place I would be on a good weather day !!

BUT. . . what staggers me is the amount of mode S equipped aircraft that operated without Mode C (We can tell) either off due lack of equipment knowledge, deliberately switched off (there was was a 14 page thread on flyer about that) or unserviceable.

On one side there are those who demand the right to fly no radio no electronics etc and the other, those whom fly commercially whom want as many layers of ALARP safety as possible. I actually don't think it's the CAA or any ANSP responsibility; it's yours! Get your BGA, BHA, GA alliance et all together to see if they can establish a minimum operating standard to aid airborne conspicuity.

This is the 2nd time this year I've sent radar recordings to the AAIB - 2 times too many.

Stay safe all - Fred
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Old 18th Nov 2017, 09:50
  #110 (permalink)  
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ADS-B can help reduce airspace infringements and mid-air collisions, says CAA


ADS-B can help reduce airspace infringements and mid-air collisions, says CAA ? Future Airspace Strategy VFR Implementation Group
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Old 18th Nov 2017, 09:53
  #111 (permalink)  
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I just wanted to add my condolences. I was once part of a small group that collected the wreckage of a glider that had been in a mid-air. It was a sobering experience.

I also wanted to make an observation from the point of view of someone who has a background in psychology, though not in cognitive psychology, which is the relevant field here. Anyone who puts their trust in the human cognitive system should look at the articles on Wikipedia that discuss *change blindness* and *inattentional blindness* (can't post the links). And they could do worse than look at some videos by Dan Simons and Chris Chabris, which are easy to find on YouTube (once again, sorry I can't post the links).

It is important to recognise that, even if something is right in the middle of your field of view, your cognitive system may not pass that information to your consciousness. I am not taking sides in the debate about TCAS or anything else, just saying that every system has limitations, but I suspect that not everyone is aware of the extraordinary limitations of human equipment. Perhaps a short course showing those limitations ought to be part of pilot training, if it isn't already. The same goes for driving.
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Old 18th Nov 2017, 09:54
  #112 (permalink)  
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Originally Posted by wealthysoup View Post
Indeed, it is called multilateration - unfortunately a term that a lot of people aren't familiar with.

Where does the accuracy of 50m for x,y,z come from? I've never heard of a specific accuracy for FR24 but would be interested to know if its implentation of MLAT really is that accurate.

I'm afraid that the "radar site" getting time and position from a GPS attached to the receiver is outdated by several years. Whilst a GPS can be used, flightradar allows users to enter X,Y and Z of their receiver (or more specifically their antenna) without ever having to connect to a GPS. If the GPS was (still) a requirement then the data would likely be a fair bit more reliable.

Edit: Just googled - Here is the official accuracy statement for MLAT from the flightradar blog: "MLAT position calculations have a general accuracy of 10-100 meters and 1000 meters in the worst cases."
We are talking about utility non professional service,
which is not certified,
have no intention to be navigational aid,
just for informational use,
On the other hand that area is have fair coverage with F- kind of FR24 hardware where GPS is ON 7/24/365 and position can not be "written by
hand" and time domain timing is not estimated through network but sourced from GPS timing.
Which is slight difference to T- kind of devices mostly self home-made out of good SDRdongle, RPI2or3, fair 1 GHz range antenna, good net, with or without GPS present.

Here, have both and experience of more than 4 years of 24/7/365 monitoring is that accuracy of MLAT on S type of transponders is within
20 m range. There are also several other pilot implementations of similar time domain MLAT technology for example in SAR use. Have some
experience on that too.

Let's see official report but expect no surprise, the plank was above
and behind on 7 to 8 diving on poor souls in G2

Edit / this post just confirm that the data for FR24 was enough to have fair estimation of position:
Originally Posted by ATCO Fred View Post
Sadly I watched this accident on radar . . . . both Mode S equipped squawking A and C.
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Old 18th Nov 2017, 09:58
  #113 (permalink)  
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Leon & Ruth. The reputation and quality of the training HS provides is second to none. Like many, I've been welcomed into your family and learnt so much, way more than mere EASA regulations, from excellent aviators and instructors. Yesterday's tragedy may seem catastrophic right now but I know you will find a way through.
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Old 18th Nov 2017, 10:00
  #114 (permalink)  
Join Date: Aug 2007
Location: UK
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It is a very sad day at HS
We have lost a great Instructor and friend through no fault of his own
He was inspirational for so many students and will be greatly missed by us all
Now is not the time for recriminations but to remember a great guy and also his student who was also an innocent victim
May they both RIP
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Old 18th Nov 2017, 10:07
  #115 (permalink)  
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Sadly I watched this accident on radar . . . . both Mode S equipped squawking A and C.
And thereís the thing. There were probably quite a few who saw this on their radar displays or FR24. The information to prevent this was out there, in almost real-time. But the people to whom it would have made the greatest difference didnít have access to it.

That has to change.
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Old 18th Nov 2017, 10:11
  #116 (permalink)  
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Originally Posted by PerPurumTonantes View Post

I used to fly in the USA and if I remember correctly you could easily get a 'flight following' service giving deconfliction (can any US pilots confirm?) Was amazed to find that in the much more cramped UK airspace, LARS is seen as a luxury.

It's like the English feel awfully embarrassed to have to bother those busy chaps at Farnborough.
I hold both EASA & FAA licenses and fly in both countries. You cannot compare the US Aviation Infrastructure to that of the UK. The US has far greater govt support and funding.
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Old 18th Nov 2017, 10:23
  #117 (permalink)  
Join Date: Aug 2017
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Originally Posted by noblues View Post
my view is it has no place in GA.

I've found the Mk1 Eyeball system very reliable for GA VFR that requires zero investment and is by default carried on board every flying machine.
TCAS saved me a head on collision flying back from Milton Keynes to Wycombe in the evening sun.

And good lookout saved me a collision with someone merrily joining base the other day without a single radio call (different airfield).

You're right, good lookout is paramount. Also that TCAS has flaws and isn't ideal for GA in dense traffic. But for me it was a lifesaver.
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Old 18th Nov 2017, 10:43
  #118 (permalink)  
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Originally Posted by 9Aplus View Post
Let's see official report but expect no surprise, the plank was above
and behind on 7 to 8 diving on poor souls in G2
PFL with incomplete HASEL?
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Old 18th Nov 2017, 10:48
  #119 (permalink)  
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The daytime alternative is this:-


But, either way its going to bring the pains on with operators who like doing things the same way as they've been doing since 1346 and who no doubt claim that the cost of adoption will cause cracks to open in the earth's crust . . . Armageddon . . Etc - read minimum wage and maternity/paternity leave.

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Old 18th Nov 2017, 11:19
  #120 (permalink)  
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Originally Posted by ATCO Fred View Post
Sadly I watched this accident on radar . . . . both Mode S equipped squawking A and C...
I see yer a Pom. Though you may know why ADS-B were instructed to be turned off for Oshkosh ?

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