Powered flights over gliding sites

Voiceover 0:16

Welcome to the CAA Safety Files podcast.

Nathan Lovett 0:29

Hello, and welcome to the Safety Files podcast from the UK Civil Aviation Authority. I'm Nathan Lovett from the CAA's communications team. And in this series we look at occurence, incident or accident reports that have been published throughout the different areas of the UK aviation industry. We focus on a different report in each episode, and hear from aviation experts to find out what can be learned from it. Now the CAA has recently run a safety campaign highlighting the potential dangers when flying near or over active gliding sites. And there's been a lot of interest in that both from general aviation pilots who fly powered aircraft, and also from glider pilots. So in this episode, we're going to look at a recent report that was made after a glider and a Cessna came quite close to each other in the air above a gliding site. The glider pilot reported this to the UK Airprox Board, also known as UKAB. And we're going to hear about what happened and how the Airprox Board went about reviewing the incident. Here to help explain everything is Simon Oldfield, who is the Director of the UK Airprox Board. Thanks for your help with us, Simon, please can you start by telling us about your role and your background in aviation?

Simon Oldfield (UKAB) 1:32

My background is '85 I joined the RAF, started flying in the RAF in '90. Graduated as a navigator and then went on to Tornadoes, flew Tornadoes for the majority of my career in the backseat, did a short while with the French as well. And then I finished my RAF career back in '19. And during that time, my last job in the Air Force was a member of the UK Airprox Board as one of the Board Members, then left the Air Force and joined the Secretariat, which is is essentially the hub of the Board's activities as an inspector. And then last year, when the previous Director left, I was promoted to the Directors post.

Nathan Lovett 2:20

Some of the people listening to this will be very familiar with the UK Airprox Board and what it does, but for those that aren't, can you talk us through what the organisation does and the remit that it has, please?

Simon Oldfield (UKAB) 2:29

Absolutely. So I think the first and most important thing to say is that the UK Airprox Board does not investigate near misses in the UK. There's a lot of misunderstanding out there that thinks that we go out and conduct investigations. Unfortunately, we don't have the staff to do that. So what we do is we rely on other organisations who are required either by regulation or voluntarily, to conduct their own investigations, and we collate all the evidence that's gathered. So we'll take the reports from the pilots that are involved, reports from the controllers that are involved. And any other investigation reports that may have been raised, for instance, by an Air Traffic Control unit who are required to conduct an investigation when there's an airprox. I'll gather all that information together, and then we'll present it to the Board. So the board is exactly 15 people from various aviation backgrounds, who will sit and read the reports, where they will discuss those reports, and then they will assess the risk of collision. And also attribute various contributory factors. That's changed from about two or three years ago, the Board used to come up with a cause and a risk. But modern thinking is that there's never any single cause to any incident. So the Board will try and evaluate to the extent that they can find out what factors contributed to the airprox and the risk of collision.

Nathan Lovett 3:46

And it's important to mention that you publish airprox reports, those come out monthly, is that correct?

Simon Oldfield (UKAB) 3:50

Yes, it is. The board sits every month. And then straightaway, after that, we'll go back and we'll collate all the evidence, put it all together at the end of the report. And we'll publish those usually about four weeks after the board meeting. And that happens 11 months of the year, there is one month off, which is August for the simple reason that most of the board members are on holiday. And I would like to mention actually at this point that those that sit on the board are all volunteers. So they come from all sorts of walks of life, from the gliding fraternity, airlines, private pilots, air traffic controllers, from area radar, from little airfields. So there's a wealth of experience in there, but they're all volunteers. So we do give them a month off in August and we don't have a board meeting.

Nathan Lovett 4:36

So as mentioned with this podcast, we focus on a different report in each episode to look at what can be learned from it and also to cover the relevant safety guidance. And for this episode, we're looking at one of the airprox reports that you just mentioned. Can you talk us through the incident and what happened, please?

Simon Oldfield (UKAB) 4:49

Yeah, sure. Okay, so this airprox was initially reported to us by the pilot of a glider an ASK 13. They just launched from Aston Down, on the winch, and shortly after they'd released the winch was setting themselves up for their next activity. A powered aircraft flew underneath them from south to north. So obviously a little bit shocked by this so they filed an airprox and we then took that airprox and went through our processes. As it transpired, the pilot of the powered aircraft did actually see the glider but at quite a late stage.

Nathan Lovett 5:24

How common is it for UKAB to receive reports relating to flights over gliding sites?

Simon Oldfield (UKAB) 5:29

Well, obviously we receive a lot of reports in different parts of the FIR but we are noticing that there are quite a number that we see where a powered aircraft has overflown a glider site. Now it's important to stress of course, that on the VFR charts, as issued by the CAA through NATS, there is a circle around glider sites that doesn't signify any airspace or anything. It's just to highlight the presence of the glider site and this is Class G airspace, and therefore, anybody is entitled to operate in that airspace. However, there is always the question that even though you can operate in Class G airspace, you have to ask yourself, well, what's the chances of me encountering another aircraft? Obviously, even though that's a glider site, there's no airspace associated with it. We know that gliders are going to be taking off and landing from that site. So flying overhead the site probably does increase the chances of coming close to a glider.

Nathan Lovett 6:18

You mentioned that the board meets monthly to look at incidents like this, what type of information did you have for this specific incident?

Simon Oldfield (UKAB) 6:24

Okay, so as I previously mentioned, we got the initial report from the glider pilot, who was reporting the airprox; They didn't have any information on what the powered aircraft was. They just said that, well, I think it's one of these. And then we go off, and we try and trace the second aircraft. It was quite straightforward to trace the second aircraft. And we then requested a report from the pilot of the other aircraft. So we've now gathered an account of what happened from the glider pilot and an account of what happened from the pilot of the powered aircraft. There was also a ground element involved here, which was the AFISO at Kemble. So we asked them, if they'd submit a report, which they kindly did, they didn't have a great deal to add, but they were kind enough to give us a report. And then at the Secretariat we will also will go and have a look at the rules, the regulations, anything that's published, say, for instance, around local operating procedures at Kemble, or whether there are any agreements between Kemble and Aston Down, because they are quite close to each other. And we'll put that into the report for the board members consideration as well. And then once we've gathered all of that together, that's when it goes into the board meeting, and the board members will sit and discuss the incident.

Nathan Lovett 7:28

The report goes into detail about what the board discussed as they worked through this information. Please, can you tell us about this and the analysis process? What types of things were being raised by the board at this point, as you worked through the information together?

Simon Oldfield (UKAB) 7:41

We'll normally ask for the expert opinion of a glider member if there is one in the room, and there usually is. So we'll ask a glider pilot member what they think of the incident, we'll also ask a member who can represent the community from which the other aircraft comes, in this case, a General Aviation powered aircraft, we have plenty of pilots in the room that actually do this. And so we'll ask them for their opinion on the actions of the glider pilot the actions of the powered engine pilot, and also of Air Traffic Controllers or AFISOs in the room and say, well, what do you think about the AFISO? What about this? What about that? And we'll also look at how either local procedures, or even national procedures, were applied. Were they applied correctly, where they applied incorrectly. Why do we think that was if they weren't applied? Was it because somebody was trying to avoid weather? And they couldn't do that? Or was it because of some other extenuating circumstances. I'd just like to say that it's very, very, very rare that the board considers that a pilot has perhaps willfully disregarded rules. So in this case, the board discussed the actions of the glider pilot, discussed the actions of the powered aircraft pilot, and the AFISO to see if there's anything perhaps that the board recognised that they maybe could have done differently. And I think the big question here that was presented to the board was, "what were the reasons that the powered aircraft pilot had for the type of departure they flew from Kemble and the track that they took immediately after departure", which took them straight through the overhead of Aston Down, which again, is perfectly permissible within the rules. And I think that the board's analysis was that, actually, realistically, there was no reason that was obvious to the board as to why the powered aircraft pilot had chosen to track directly over the top of the glider side, when they could have gone to the east or to the west of it, acknowledging that there are other considerations like airspace, etc. But the board could't see a reason on this occasion, why they'd chosen to go straight through the overhead. It's also worth mentioning that there are procedures in Kemble where if you inform the AFISO that you're headed in that direction, they'll tell you whether or not they think Aston Down is active. And Aston Down will normally let Kemble know when they're active. And that's the AFISO and then tell the AFISO you're going that way. and they'll say caution, Aston Down is active. On this occasion, the pilot did not inform the AFISO of their intentions. Therefore, the AFISO didn't know that the pilot intended to go that way, and therefore couldn't let them know.

Nathan Lovett 9:50

The report also talks about the contributing factors that were identified for this incident. Can you talk us through what they are?

Simon Oldfield (UKAB) 9:56

Absolutely. It's really important for the board to try and identify what factors contributed to an incident because no two incidents are ever the same. But often we find that the same kind of things lead to incidents occurring. On this occasion, there were certain things about the planning on the part of the Cessna pilot, where they didn't let anybody know that they intended to turn right after departure in the direction of Aston Down. And of course, the board actually did wonder whether or not the pilot of the Cessna had taken full account of Aston Down's proximity and presence with respect to their airfield of departure. They were visiting and actually returning home afterwards. Things that do crop up very, very commonly in our airprox incidents, are situational awareness of each pilot, that is to say, had they had any information, which might tell them that that other aircraft was there. So on this occasion, the glider pilot had no information to indicate that that powered aircraft was going to be there. And the powered aircraft pilot, the only information they had actually was that there was a glider site marked on the chart. So I guess you could reasonably expect there to maybe be gliders, but that's why we all look out of the windows, right? You know, we look out to see if there are any other aircraft about so, you know, it's a perfectly legitimate defence against mid-air collission is to look out of the window and see if you can see anything and if you don't see anything, and hopefully nothing's there. So in this case, the board concluded that one of the pilots had absolutely no situational awareness of the presence of the other aircraft, that was a glider pilot. And the other one, the only awareness they had was that there might be gliders there because there's a glider site, but didn't know exactly where that other glider was. There are other things as well that can contribute. For instance, most gliders in this country carry electronic conspicuity equipment. Unfortunately, most of that electronic continuity equipment isn't really compatible with many other forms that are carried by powered aircraft. There are some manufacturers who make electronic conspicuity equipment can see a multitude of different types. On this occasion, the equipment carried by the Cessna pilot couldn't see the equipment on the glider, and vice versa. The gliders equipment couldn't see the stuff on the Cessna. So they didn't even have that the electronic warning systems working for them either. So it really came down to both of them looking out of the window and avoiding what they saw. Of course, we all know that the human eye is fallible, and that it's easy to miss things. And actually, if you're on a direct collision course with another aircraft, it's pretty widely known that they're very, very difficult to see because there's no relative movement and the human eye, or the human brain is very good at kind of disregarding something where there's no relative movement. So you're kind of at last chance saloon when you're on the lookout, and the board's thought, well, fortunately, one of the pilots saw the other aircraft in time to do something, but they saw it so late that they didn't really have enough time to completely remove the risk of collision. So the board assessed that there was a little bit of collision risk there in the end, but that one of the pilots did manage to do something to generate some separation, but certainly not separation that you'd be typically comfortable with.

Nathan Lovett: 12:55

We talked a little bit about the Board discussions, we've looked at the information that the board had available and the contributing factors that were identified. And this all led to the board making a recommendation about this specific incident. Can you tell us what that was please and why that recommendation was made?

Simon Oldfield (UKAB): 13:10

So the board discussed actually, pretty much from the AFISO's comments. So the AFISO provided about four or five lines, you can read those on page two of the report, suggesting that if the Cessna pilot had let them know that they were going to be turning out and heading to the north, then the AFISO would have informed them about known activity at Aston Down. So the board thought that perhaps there was an opportunity missed here, that if a powered aircraft pilot who's either departing from or arriving to Kemble, if they don't know about Aston Down, they haven't got information that they can then use to plan accordingly. In this case, there's no question that the Cessna pilot really should have said that they were going right, and then they would have got the information. But actually irrespective of which way they're going, it would be useful for pilots to know about this. And equally when pilots are arriving, even from the south, it might be useful information to them that Aston Down is active because if they have to go around to the north, then they're going to be looking to take that information into account. So the board decided they'd make a recommendation on Aston Down and Cotswold Airport, which is the other name for Kemble to work together to establish a mechanism for this passage of information to pilots coming in and out of Kemble.

Nathan Lovett: 14:18

One of the themes we keep returning to with this podcast is how important it is that people make reports if they see something that doesn't seem right. And in this case, we only know about the incident because the glider pilot reported it. So in general terms, when should people make a report to the UK Airprox Board? And how should they do it?

Simon Oldfield (UKAB): 14:35

Well, that's a nice and easy one to answer really the definition of an airprox, and I'm going to paraphrase here so so I apologise for the paraphrasing, but it's a situation in which in the opinion of a pilot or controller, and the important word in that is 'opinion' of a pilot or controller; the relative positions of the aircraft have been such the safety may have been compromised, or words to that effect. Important words there are 'pilot', 'controller' and 'opinion', there's no threshold for this. If you think the safety of your aircraft may have been compromised by the presence of another aircraft, then it's an airprox report. And I would encourage people to report to us if they if they feel that that's the case. For gliders in thermals, frankly, you know, 15 metres away from another aeroplane is plenty of room. But if the aeroplane is going the other way, and you weren't expecting to see it, and it's the same altitude as you, 15 metres is probably very, very, very close. And there's all sorts of distances in between that you could consider. So the way to report to the UK Airprox Board is either through the UKAB app, or preferably online through the UK Airprox Board website. And if you google UKAB, we're the first hit in the UK, and then there's a link there to the report form. it should take no longer than 10 to 15 minutes to complete. And that will permit then the Secretariat to do its work to go and trace the other aircraft and then to gather as much of the evidence together as we can to present to the board, to learn as much as we can from the incident.

Voiceover: 16:06

You're listening to the CAA Safety Files.

Nathan Lovett: 16:13

That was one specific incident involving overflight of a gliding site. And we're now going to look at this in more general terms. David Pratt from the CAA Communications team recently visited a winch launch site near Cambridge, and spoke there with Andrew Watson, an experienced glider pilot to get his perspective.

Andrew Watson: 16:30

So my name is Andrew Watson. I've been flying gliders for about 30 years. We're here today at Gransden Lodge airfield, which is the home of Cambridge Gliding Club and also the Affiliated Cambridge University Gliding Club,

David Pratt: 16:44

And currently host to this year's Inter-Unis gliding competition. So there are plenty of student pilots and instructors around as well as club members who fly regularly from here. We've just come out of the pilot briefing, and they're lining up gliders for winch launch pretty much as we speak. But I've taken Andrew away, and I would like to start asking about the scale of the overflight issue for gliding clubs and glider pilots in the UK. How common a problem is it?

Andrew Watson: 17:12

Well, let me tackle this question in two ways. First of all, here at Gransden Lodge, we have an air safety reporting system, we encourage anybody who sees an overflight that might be below our maximum winch height to report it internally within the club. And then the safety officer may well write to the pilot who overflew, just to warn them that we are here, and that this might not be a good idea. And we were running in recent years, we've been running about one of those reports a month. Meanwhile, nationally, the British Gliding Association, which is the sporting body for gliding, had a reporting initiative just before COVID, and in the year before the first lockdown started in March '20, there were about one hundred and thirty of these overflight incidents reported at gliding sites up and down the country. And I'm convinced that that isn't the full picture. I'm sure there were other incidents that didn't get reported, for whatever reason. So a lower abound on the number of overflights we're having at UK winch launch sites in a year is about one hundred and thirty. And, just to just to say, once again, every one of those incidents could have been a very serious accident if there had been a winch launch in progress at the moment that that aircraft overflew that winch launch site.

David Pratt: 18:37

And Andrew, you and I have talked before and I know that you've witnessed an incident that has really stayed with you.

Andrew Watson: 18:43

When I was the safety officer at this club, I was receiving about one report a month of an overflight. And I personally have seen a couple of those incidents. There's one in particular that has stayed in my memory because the aeroplane the GA aircraft that overflew the airfield, came very close to a glider that was on the winch. We are obviously concerned about the possibility of this happening. Normally, when we're flagging these incidents, it's because a GA aircraft overflew the field, and there was nobody winching, but it could have happened it could have happened that a winch launch was in progress at that time. But on one particular occasion, I witnessed a light twin a Piper Navajo fly overhead the airfield at about one thousand eight hundred feet AGL just as a winch launching glider got to the top of its winch launch at about one thousand nine hundred feet AGL. And from where I was standing on the ground, I had a grandstand view. My estimate was that the Navajo went about one hundred feet underneath the glider that was at the top of the winch launch, and was probably about five hundred feet laterally in front of it. So it was that close not only to the glider, but also to a couple of thousand feet of steel cable,

David Pratt: 20:03

So there's a real element of chance isn't there when we're talking about this risk, whilst thankfully, cable strikes remain uncommon, the significance of one is enough to warrant taking it really seriously.

Andrew Watson: 20:14

Yes, I mean, we are very lucky. And I'm afraid that luck does play a major element here, we are very lucky that there have been no cables strikes in UK gliding in the last two or three decades. But when we start a launch, a winch launch, the ground crew will, of course, visually check the vicinity of the site and will not start the launch if they see an aircraft is about to over fly us. But if you're flying towards the winch site at 120 knots, you're covering two miles a minute. So quite likely, the ground crew won't be able to see you, or indeed hear you, as you're approaching. They'll be convinced that it's clear to launch they'll start to launch. A winch launch takes probably one to one and a half minutes, all told. Of that time, the glider may be going up the winch for maybe a minute. And then for a further 30 seconds or so the cable will descend under a small parachute and still be a threat to anybody who's over flying the site. So yes, I think in this particular case, we had looked around we had checked to make sure there was nobody approaching the site. But this aircraft was flying pretty quickly. By the time a minute and a half later, a minute later, the Navajo arrived directly over the site. Yeah, it came very close to the, very close to the glider.

David Pratt: 21:35

And in terms of look out at launch, the glider's looking to be pitched at around 45 degrees when it's on the cable. So one can imagine the limited view for that minute or so. But once the glider is off the winch and in free flight, what kind of altitudes would you be reaching? Because you've got cloud level that many pilots of powered aircraft are going to be staying below.

Andrew Watson: 21:56

Yes, so we the reason we winch launch is of course to get the gliders into the air. And there are some days when all we do is winch to whatever altitude you can achieve with the winch, and fly around descending through the air the whole time and land again after a seven or a 10 minute flight, and particularly when we're training, that's quite common. But for most glider pilots, the reason we fly gliders is to go soaring, that's to say to find rising air and use it to climb, and to stay in the air for long periods of time. Not only can we stay in the air for 2, 3, 4 hours without burning any fuel at all, wthout using an engine at all, but we can climb potentially all the way to cloud base. If you're flying near a gliding site, there could be gliders at any altitude in the vicinity from you know, a thousand feet above ground level all the way up to cloud base. Glider pilots, unlike our GA cousins, every glider pilot is allowed to fly in IMC clear of cloud all the way up to cloud base. So in Class G airspace that means we can be within 100 feet of cloud base at four thousand feet AMSL, whereas our power flying cousins would have to have an instrument rating to be there to be close to cloud above three thousand feet MSL. So any altitude up to cloud base.

David Pratt: 23:16

And thinking about the vicinity around a launch site where a pilot might expect gliders flying, at this morning's briefing I think NOTAMs were covered for a radius of 29 kilometres around the site?

Andrew Watson: 23:28

Yes, so if a glider pilot is going to fly across country, and that means making a cross a flight away from the site of 100, 200, 300 or even more kilometres, it is that pilots own responsibility to make sure that they've checked obviously, that they've checked all the NOTAMS for the route that they're going to follow. For training and for local flying the instructor in charge on the day will check NOTAMs for a smaller circle around the site. And they picked 29 kilometres as being that radius. So yes, NOTAMs are definitely something that we take seriously, the Duty Instructor will check NOTAMs for people who are flying locally, people are flying further away check there are NOTAMs.

David Pratt: 24:09

Do you think there's an issue of the powered pilot community not fully understanding either the detail of the launch, or the altitude to which gliders can, can fly around the site?

Andrew Watson: 24:19

No, I'm absolutely certain of it. I mean, nobody would deliberately fly overhead a gliding site where there could be three thousand feet or so of steel cable vertically up and down over the airfield, if they realised that that was indeed, was the the situation. In the UK there are about 80 gliding sites which winch launch, they all winch to at least two thousand feet above ground level. Many of them winch to three thousand feet above ground level and in the right conditions, particularly strong wind conditions, we can achieve those kinds of launch heights.

David Pratt: 24:54

What do you think can be done to help pilots of powered aircraft acknowledge the risks? And do you think there is an element of different groups of pilots not fully understanding each other's environment?

Andrew Watson: 25:05

Yeah, no, you're absolutely right. I think the key, one of the keys to solving this problem is mutual understanding, mutual education. I certainly don't know or understand everything about operating powered aeroplanes of these kinds. But if people who fly particularly GA, fully understood, the way that we winch launch gliders, exactly what the symbology on the paper chart means, that little slash 3.3 or slash 3.6 next to the G symbol that marks the gliding site on the half million chart. That means we could be winching to three thousand three hundred, three thousand six hundred feet above sea level. The cable that we use can be 4.5 millimetre stranded steel, it has very high tensile strength. A couple of thousand feet of that wrapped around your wing really would not improve your day. And I think that a large part of solving this problem is education. Nobody wants to introduce more regulation, nobody wants to restrict the airspace overhead gliding sites to be just be dedicated to gliders. Glider pilots are the last people who want to increase the number of restrictions on where pilots can fly, because we enjoy flying all over the country, as far as we can in Class G airspace. So regulation in my view is not the answer. The answer is education. And also, I would like to see a focus on the way that winch sites are represented on moving map cockpit displays. Everybody who flies cross country these days, uses a moving map. It's the right thing to do. It helps you navigate, helps you stay out of airspace. But we need to make sure that these moving maps adequately warn the user if they're about to fly into an area where there might be a winch cable. We have danger areas represented on these moving maps. We have controlled airspace represented there. The moving map will warn you to stay out of those areas. I would like to see your moving map warn you as insistently if you're about to overfly a winch site, as it would do if you're about to violate Class A airspace.

Nathan Lovett: 27:27

Thanks to Andrew Watson, who you just heard there and also to Simon Oldfield at the UK Airprox Board for speaking with us. Now, as mentioned at the beginning of this episode, the CAA has recently run a safety campaign highlighting the risks of flying over gliding sites. And you can find more information on that, including guidance for pilots online at caa.co.uk forward slash gliding sites. We've included that link in the episode notes, along with the airprox report that we talked about with Simon earlier. So that's it for this episode, but if you have any feedback or suggestions for future episodes, please contact us at safetyfilespodcast@caa.co.uk Thanks for listening.

Voiceover: 28:17

Thanks for listening. This is the CAA safety files podcast.