Episode 9

Published on:

11th Aug 2023

Active carbon monoxide detectors

We chat about the latest on our active carbon monoxide detector project. In particular our latest survey which we launched at AeroExpo in June. We also hear from members of the GA community on their thoughts on what sort of carbon monoxide detector they fly with and why.

If you have any feedback or suggestions for areas that you’d like us to cover in this podcast, please get in touch at gapodcast@caa.co.uk.

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Voiceover 0:11

Welcome to the general aviation podcast from the UK Civil Aviation Authority

Alex Blomley 0:22

Hello, and welcome to a bonus episode of the UK civil aviation authorities general aviation podcast. My name is Alex B;omley and today we're going to be talking to you about active carbon monoxide detectors. Some of you may have heard about our new survey into the use of active co detectors that we launched at AeroExpo a few weeks ago. Feedback gathered through the survey will help to shape the future use of these devices and how they could be used in piston engine aircraft. evidence to date indicates active co detectors capable of alerting pilots by oral and all visible warnings, or net safety benefit all pilots and their passengers. And while the risk of CO poisoning may be known and understood by many GA pilots, the same cannot be said for consumers and third parties. Generally, you may fly in piston engine aircraft on a commercial or recreational basis. This is an important project. And we would appreciate you completing the survey if you've not done so already. The link to this will be included in the podcast notes. And we'd like to thank those of you who have completed this already. We do really appreciate your time in doing that survey. So last year, and in one of our very first GA podcasts. We spoke with Thomas Weir, from our policy team who was leading on this carbon monoxide project. And it's great to be able to welcome him back today. Hello, Thomas. Thank you for joining us,

Thomas Weir 1:44

Alex. It's great to be here. And thanks for having me back to provide an update on this important topic.

Alex Blomley 1:50

Thank you, Thomas. It's great to have you. So when we last spoke, you were about halfway through a 12 month study. The final report of that study was published a week or so ago. Can you share the key findings that you learnt from that activity?

Thomas Weir 2:05

Absolutely. So I'd first like to again, thank the one hundred or so volunteers who who signed up to the 12 month study, agreeing to complete the monthly surveys for a year really was a big commitment on their part. And getting that data has been very helpful for us, and has improved our understanding of how these low cost active co detectors, performing GA aircraft. So we really appreciate the commitment from all the volunteers. In terms of the key findings from the study, let's say an important reason for conducting it in the first place was to gather data on CO alerts over the course of a full flying season. And whilst most participants in the study didn't experience any alerts throughout the 12 months period, which is obviously a good thing, about a quarter of them did. So one finding that it came as a bit of a surprise to me actually was the number of CO alerts that took place on the ground. So during startup or taxing so yeah, we found about 60% of all alerts in the study were underground. We also found it quite a small number of participants made up a significant proportion of the total number of reported alerts. So for example, about a third of all the alerts during the study came from just three participants. And about half of all the alerts came from just five. So it was very, very concentrated. We also noted a small increase in the number of CO alerts during the colder months, which is something that we expected to be honest, and it's in line with other studies as well. But nevertheless, it was good to confirm that. The results from the study also confirmed that the number of CO alerts tends to increase with aircraft age. Again, this was something that we were expecting. About two thirds of all seal alerts involved aircraft were at least 41 years old. Naturally, about 85% of all alerts occurred on aircraft that were at least 31 years old. So I should point out as well that there was a large number, a larger number of older aircraft participating in the trial. But even when we adjust for this fact, we still found that older aircraft experienced more alerts. It is worth emphasising though that CO can be an issue for any aircraft irrespective of age. The full list of findings is included in the final report that was published. That's it, the real positives from the study was just how well these low cost active co detectors performed. Clearly they're not perfect, but I think the study showed that their net safety benefit and can offer pilots and passengers good protection from CO whilst also being very cost effective.

Alex Blomley 4:59

Thank you for that Thomas. So for those of you listening who are interested in reading the report that Thomas was taking us through just then, we have included a link to that in our podcast notes. And we've also updated all of this information on our carbon monoxide webpage that we have on the GA section of the CAA website. So Thomas, alongside the report that we published, we've also shared an updated safety notice as well, I was able to go through the core update of that as well, please.

Thomas Weir 5:31

Sure. So I think the the safety notice already had a lot of very useful information in which we've kept. However, it was last updated a couple of years ago, in April '21. So even before the 12 month study of the low cost active co detectives had even begun. So we felt it was probably long overdue and update and it was worthwhile to give it a refresh as things have moved on a bit since then. And in particular, as I just said, the 12 month study has concluded and it's yielded some interesting and valuable insights. So we thought it'd be worth including those in the safety notice.

Alex Blomley 6:12

Yes, that makes sense. And as I mentioned right at the beginning, we are running a new survey this summer. We launched that a few weeks ago. And Thomas, it'd be great to learn more about what you're hoping to gather and learn from GA pilots on the completion of that survey. Yeah, sure.

Thomas Weir 6:29

As you said, we ran a survey in the summer of '21. To gauge GA pilots awareness of CO is a risk. And it was also an opportunity for them to share their experiences with us of dealing with CO. Having done quite a lot of work in this space. Since then, we're keen to understand if we've had a positive impact on increasing pilot awareness of CO. So to help assess this, or asking pilots if they fly with any form of CO detected, just as we asked him in '21, just to see if there's been a positive shift. And from an initial look at the responses so far, we can see that about 77% of respondents have indicated that they do fly with an active CO detector, which is really great to hear. And it's an increase on the 50% from two years ago. So that's very positive. There are also some new questions in the survey as well. So for example, we're also keen to hear from GA pilots get their thoughts on whether flying with passengers means it's it's more important to have a co2 detector. Since passengers may not be aware of the risk posed by CO when they get in a in a piston engine aircraft, or at least maybe not to the same extent that a qualified pilot is aware. We also have a question asking if there are any aircraft types that pilots feel are less susceptible to CO, due to the configuration, we recognise that the GA fleet is quite mixed. It's it's a very varied fleet. So we're keen to get people's thoughts on this as well. And since we do want to encourage more pilots to fly with an active co2 detector, the survey also asks what would convince a pilot to start using one of these devices, we've seen a few initial responses from people who rent aircraft from flying clubs suggesting that the decision to have a an active CO detector is not theirs to make. Since they're not the aircraft owner, I would strongly encourage the owners of club aircraft to fit active co detectives to their fleet. And by protecting the individuals who rent out the aircraft, you're in turn, protecting your asset, the aircraft itself. But I would also say to pilots who may be renting these aircraft, there's a wide range of cost effective active co detectors available. And it's never been easier to purchase a portable device that you can take with you. It's going to protect yourself, as well as your passengers from CO, rather than leaving it in someone else's hands.

Alex Blomley 9:06

So it's great to hear some of the responses that have come through from that survey and some really interesting points being raised there about aircraft ownership and responsibility. So when we were at Aero Expo, we were fortunate enough to be able to have chat with a few GA pilots on this topic, and the use of CO detectors. And this is what they had to say. Nick heard,

Speaker 4 9:27

I'd been flying of sorts of 40 odd years professional pilots route, sort of equal military and civilian. And at moment I'm sort of concentrating on ppl instructing as as an instructor and as the examiner. We do have a standard sort of strip type carbon monoxide indicators, which we teach our students to keep an eye on. But that's as far as we've sort of taken that particular aspect of carbon dioxide monitoring. Having seen the presentation earlier on today, learned a bit more about and then yes, I can see the logic of using active co monitor, given the sort of aural sort of warning capability that it gives us well, and indeed the fact that it's more or less an off the shelf type product and would go into an aeroplane, pretty straightforward, like perhaps like a ELT or something like that. Yes, I can see now having seen little bit more about it, that might be a good idea to have an aircraft.


Nick Brooks, I fly a 3x is microlight SkyRanger. I've passed my test about a year ago. Now, I want to minimise the risk of me dying. And that's a good way of doing it. I can't see the gas, I can't smell it. So if I can help myself, avoid it, then I will.


Ian Shepherd. I've been flying since '91, had a big break, and then picked it up in '14. Again, and then became an instructor in '16. All GA No, no airlines or anything like that.

Alex Blomley:

Do you happen to fly with an active carbon monoxide detector?


Yes, I do have one in my bag, because I'm instructing in various aircrafts. So I have one in my bag. fairly cheap one, but it works. That's in my bag all the time. So I would always have my flying bag with my licence and everything as well. So it's, it's all in there.


Malcolm Smith, I've been flying for about 25 years currently fire Piper Arrow. We've had a spot on for a while I've been considering buying a better one to replace that with you. I've seen your surveys coming around. So I think yeah, I guess my question has always been, should I have one that's aircraft specific? Or can I just use any one from like being here or somewhere.

Alex Blomley:

And one thing that did come up when we were talking to pilots, there was a slight hesitation. And we can hear that in the last pilot that we spoke with over what device they should actually be buying. So I wonder, Thomas, if there was any advice that we could share on that?

Thomas Weir:

Yeah, that's a really good question, then there is a wide range of co2 detectors on the market so I can understand the confusion. The quick answer is no, you don't have to go for an aviation approved device. So broadly speaking, co detectors fall into two main categories, there's passive and there's active. Most pilots are probably quite familiar with the passive type, they're the ones that have the spotlight on them, it changes colour when exposed to carbon monoxide. The biggest drawback of these detectors is that they have no attention grabbing capability. So unless you're actively looking at it quite regularly, while you're flying, you may not even be aware that it's changed colour. By contrast, active detectives, they have ways of getting pilots attention, usually via alarms and flashing lights. And it's, it's these devices that we're encouraging pilots to consider. And again, there's a lot of choice out there. So it can be a bit overwhelming. Commercially available devices designed for home use or in motorhomes and caravans and boats are becoming quite popular amongst GA pilots. And it was actually these kinds of detectors that made up the majority of the ones that were used in the 12 month trial. And they usually cost around 20 pounds and can have a sensor up to seven years life and a battery life of up to 10 years, which makes them really very cost effective. And although they're not approved revision use, as we find from the 12 month study, they do seem to work reasonably well in the UK GA environment. So definitely a good option to consider. You can also get detectors that are designed and approved for aviation use. So these ones usually have additional functions. And you know, they adhere to specific aviation requirements. But as a result, they're more costly. They're typically around three, four hundred pounds, and then you have the installation costs on top of that, which would probably take them nearer to a thousand pounds. So if you want a more integrated permanent installation, then I'd say they're a good option, but they do come at a price. We're also seeing active co2 detectors being built in by manufacturers of other aviation equipment, such as headsets and an avionics equipment as well, which is helping to increase the presence of active co2 detectors in GA aircraft. And it's giving pilots a further option as well. So there is a lot out there, but I'm pretty confident that people can find something that's going to suit their needs and suit their budget.

Alex Blomley:

So if a pilot listening today is unsure about specifically which device they should be buying, what would your recommendation be to them?

Thomas Weir:

So in the final report for the 12 month study that we published, we did include a full list of all the active co2 detectors that we use by the pilots involved in the study. So people may find that quite useful. And then we also identified the five most popular devices that were used in the study as well. So starting with the most popular and number one, it was the fire Angel co dash nine D. This followed by the forensics detectors, car 001. In third was the voxel CO detector, which is very similar to the forensics detectives unit just from a different manufacturer. And then the fourth most popular one was the fire Angel, co 9x. And finally was the kidde 10 ll DCO, which rounded out the top five. So those are the ones that pilots in the study were using most frequently. But I've heard positive things about all of them. These are all available to do online retailers or well known DIY stores, as you mentioned, Alex. So I'd say that's probably a good starting point for anyone interested in getting an active CO detector. Additionally, I would definitely recommend pilots ask around and see what others are using, see what their fellow pilots are using. And as I said, with so much choice out there, I'm pretty confident that everyone can find something that will suit their needs.

Alex Blomley:

Thank you for that Thomas. And just to try and bring some of that to life, we have also produced a fact sheet on these top five devices that were highlighted. In that study, we have included a link to that in the podcast notes. It's also on our website. So do please have a look at that for any advice on the devices that were used by the GA pilots as part of that 12 month study. And just as a reminder, if you have not registered for skywise, we will also include a link to that in the notes. Do please register, tell your friends all about it. It was quite interesting the number of pilots at our expo that were not registered for Skyway. So we did recommend that they do so in order to get updates not just on this particular project, but on other activities that we are currently involved with at the moment. So please do register skywise. As I said, a link to that is in the notes. So Thomas, the survey will run into September, and then what will happen next.

Thomas Weir:

So we're going to be taking our small selection of active co detectors to the LAA rally, as we did at Aero Expo. And pilots will have a chance to look at them and get a sense of what these devices are like. We then plan to close the survey at the end of the summer. So early September probably. And we'll look to publish the survey findings shortly thereafter, we'll probably publish them as an infographic, which is what we did for the survey two years ago. And we've also got a Safety Sense leaflet in the works, which is dedicated to carbon monoxide. And the contents of that safety sensitive are going to be informed by the findings from the survey. So it's really important and helpful for us to get as many responses as we can from that survey.

Alex Blomley:

And I think it's also important to stress that flying with a form of co2 detector is obviously a good idea and something that we fully endorse. But of course, it does not solely mitigate against the risk of any form of carbon monoxide poisoning.

Thomas Weir:

Yeah, that's right. So prevention is always better than cure. So it's still really important that pilots and owners make sure that the aircraft exhaust and all associated systems, including the heating and ventilation system, are in good working condition. And they're well maintained. If you do have a cabin heater in your aircraft, it hasn't been used for months, maybe following a period of warm weather flying in the summer, then the whole system should be thoroughly checked before a flight where it's likely to be used. And that's definitely going to help minimise your risk of CO exposure. But I would still very much encourage pilots to also fly with an active CO detector because while maintenance is the first line of defence, the detector is always a good backup.

Alex Blomley:

And in fact, I seem to remember from looking in the report that there were a couple of responses from pilots, showing that in some cases, the car detector alarm going off had in fact been a result of an issue with a cracked manifold or some kind of problem with the exhaust. So it definitely helped encouraging the pilot in that particular case, to go back, get the aircraft in the hangar and check over the various different engineering elements to make sure that they were all fine.

Thomas Weir:

Absolutely, yeah, we did see a few incidences of pilots being alerted to a fault with their aircraft as a result of flying with a CO detector. So it's definitely a worthwhile thing to have.

Alex Blomley:

Excellent. Thank you so much for your time today, Thomas. And just to say all of the various reports and the survey link, for example have all been included. did in the podcast notes. If you have any comments or questions either on this podcast or if there's a topic you'd like us to cover then do please get in touch with us at geo podcast at ca Edie uk. Thank you so much for listening


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About the Podcast

CAA on General Aviation
The General Aviation podcast brings you the latest guidance from the UK Civil Aviation Authority with information for all types of General Aviation (GA) operating in the UK. Including updates and discussions on our current projects and areas of work.

You’ll hear interviews with representatives from our GA teams, experts on their particular fields, sharing details of their work and regulatory updates as well as highlighting opportunities for members of the UK GA community to get involved.

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UK Civil Aviation Authority .

The UK's aviation regulator