As the temperatures drop in the winter months, there are a number of challenges that come with flying in cold and unpredictable conditions.

For this episode, we’re joined by Joe Hadley and Richard Crockett from the CAA General Aviation Unit to cover the intricacies of winter flying.

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.

Related links:

• Winter flying | Civil Aviation Authority
• The Skyway Code | Civil Aviation Authority (caa.co.uk)
• Flying in Winter - YouTube
• Safety Sense Leaflet: Winter Flying
• Winter weather — Astral Aviation Consulting
• Pre-flight planning - Airspace Safety
• Carbon monoxide in general aviation
• Podcast on active carbon monoxide detectors
• Clued Up: Carbon Monoxide
• Flying with an active carbon monoxide detector - YouTube
• Night rating for aeroplanes
• Clued Up: Night Flying
• Clued Up Update: Night Flying

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

Hello, and welcome to another episode of our general aviation podcast. My name is Marnie Burroughs, and I will be your host for this session. As we’re coming into the winter season where it's colder and darker, we're going to be covering various aspects on flying safely in the winter. On the podcast today, I'm joined by Joe Hadley and Richard Crockett. Welcome both and thank you for taking the time to talk to us today. If you can please both take a minute to introduce yourself your role at the CAA and a bit about your background in aviation.

Hi I'm Joe Hadley. I'm an Initial Airworthiness Surveyor in the GAU and also a keen private pilot and instructor. My background comes from the Light Aircraft Association and here at the CAA, I won the honourable company of air pilots flying instructor scholarship in '21, and now have about one hundred hours of instructing on TMGs out of Bicester.

Hi my name's Richard Crockett. I'm a Flight Standards Officer here at the CAA. And I work with the air display regulation team. My background in flying is instructing and examining, and some air display flying.

Thank you both for the introduction. The winter can be a great time to fly if you're prepared and as you're both experienced pilots and instructors, what are the main things that people need to consider when planning to fly in the winter?

I think that's a great point Marnie, that we do see a lot of really nice winter weather when we get into this time of year. But it can also be a big threat to us, we get long periods of nice stable conditions. But that can also be coupled with the haze that we get from long periods of high pressure that's coupled with some low sun can bring some poor visibility, when we're out there flying. It can look very pleasant when you're on the ground. But that small can make life very difficult to see where you're going, especially when you're flying into Sun near the end of the day.

So one of the biggest threats that we can have in terms of winter weather is a fog and fog can occur early morning or late evening, it can often take quite a long time to clear. So occasionally we can wake up in the morning, open the curtains see a foggy day. But know that come lunchtime, it's going to be nice conditions. But I think it's really important that we do think about the kinds of environmental conditions are going to create fog. So for example, we might have a nice clear sky, we might have a falling temperature, we might have a wet ground. A lot of people think that fog can occur only really really light winds or no wind at all. But actually fog can occur in a wind speed of up to seven knots.

At the end of the day as well. Certainly around sunset fog could appear extremely quickly. Think about the time of the day, and the likelihood of fog period at your airfield. Think about if it's happened before and thinking about the conditions Richard as just mentioned that if those are the conditions in force, where you're planning on landing for could be a threat.

As you both mentioned with fog, what are some other winter weather conditions that could occur whilst flying?

So there's a number of things I think we need to think about come winter flying. And forecasting, I think is really, really important. Because it's very, very easy for us to plan to go flying on a winter's day and get caught out by rain, wind snow, the winds can typically be that little bit stronger, and the winter months, and effective window can often be a little bit more prominent. So for example, we might be faced with slightly stronger cross winds than we might normally expect. We might also find interesting effects in the local area created by things like mountain waves. And what you'll actually find that with a slightly stronger wind and a stellar conditions that you can get in the winter months, the effects of mountain waves can occur a long way downwind of mountain ranges way more than you might normally expect. So you can for example, expect to see an increased rate of climb, but also you may well find yourself flying along with quite a lot of power applied, still not climbing very well. I think it's really important just to think about, where's the wind coming from? What are the effects that local features or even features further away might be having on your aircraft?

I think there's also a great deal of useful weather information that you can find as well. Of course, there's the MET 215, the form 215, that low level significant weather forecast, and that contains loads of useful information when it comes to planning your flight. Certainly, it's very useful as well to have a look at just the local surface weather may be watching your favourite TV channel weather forecasts can at least give you an idea of what the conditions in force might be. And of course, our Skyway code has a huge section on meteorology, which is well worth having a look at the covers a little bit of what we've spoken about.

Now, another excellent winter flying resource in terms of weather is the Astral Aviation Consulting webinar. And within that, there were three experts on weather who gave some fantastic information about the kind of weather's that we can experience in the winter months, how to forecast it yourself, how to work out where the bad weather is going to be, where the good areas are going to be what to avoid. And for me, that was an absolute masterclass. In all things, weather and everything you really need to know in terms of forecasting for the winter months.

For those that are interested in learning more on astral aviation consulting, who are a third party supplier providing support and GA safety promotions on behalf of the CAA. You can find more on their activities and workshops on their website, which will be listed in the podcast notes below. Following on from our conversation about winter weather conditions, with aircraft, how does aircraft preparation differ from flying in the summer and in the winter?

I think if you're lucky enough to have an aircraft that lives inside a heated hangar, then probably not quite so different. But the reality is, a lot of us have our aircraft parked outside. So first of all, we want to be trying to remove anything that's formed on top of it. That could be rain, could be snow, that could be ice, and we definitely want to be removing ice from our wings of the aircraft. We also want to be thinking about if we're using any de icing fluid, that fluid is suitable for use on aircraft, we can't just be throwing any old chemicals over the top, make sure what you're using is actually suitable for use on your aircraft.

I think when it comes to removing ice and snow or anything else that's fallen on your aircraft or formed on the aircraft, it's really important to consider how we're going to remove that. So in terms of ice and snow, one of the best things you can do is actually try and park the aircraft in a sunny spot and let it melt naturally. But if we have a need to clear this off ourselves, we need to think about the materials we're going to use. We don't want to use anything that's going to damage the aircraft damage the airframe, we need to use materials that are sympathetic to the aircraft structure.

And of course, if we're removing this ice that might have built up on the aircraft, we need to be thinking about our own protections as well. It's going to be cold out there, probably so make sure that you're suitably dressed both for flying, but also this time that you're going to be preparing your aircraft outside. We all know that day. airfields can be notoriously windy places, but in winter, it's also going to be cold.

Absolutely. And one of the things you mentioned earlier, Jones that if we've got our aircraft and our hangar in a hangar, that's fantastic. But one of the things we need to be really careful of is getting the aircraft out the hangar ourselves, we might open the doors, find a slippery floor, pull the aircraft around, it's really easy to fall over and hurt yourself.

I know from personal experience, my aircraft has a big puddle that forms outside the hangar, which of course, I’m there wearing a fantastic pair of winter flying boots to do that. But I then don't want to get in the aircraft with all this mud on my feet as well. So I end up taking two pairs of boots to the airfield, one to get the aircraft out, one to go flying.

That’s a great bit of advice. One of my bits of background as I do lots of gliding. And one of the things that I find, particularly in the winter, when you're going off soaring and potentially doing long flights is that almost you want two sets of clothing, two sets of shoes because you want the clothes that you wear on the airfield to get muddy and wet. And then you want something that's warm and dry to put on when you go flying.

Yeah, absolutely. So when it comes to being sympathetic to our aircraft, of course, we've removed the snow and ice from it. But if it's cold outside, our batteries are really going to be struggling this time of year. If you're lucky enough to own your own aircraft and you've got power in your hangar, it might be worthwhile thinking about putting a trickle charger onto your aircraft battery. Of course, make sure you remove anything that you've fitted to it if you're going to be doing that. But we want to be sympathetic from an airworthiness point of view. Absolutely read the manual of your aircraft and understand if there's any specific instructions for operating in particularly cold climates. We do want to be sympathetic to it. The battery might be weaker in the cold weather, and there might be different instructions for your aircraft on how to start it in cold weather. And those are probably related to the priming instructions.

And what other areas of your aircraft you need to consider when preparing to fly?

One of the things that we need to do is to think about the aircraft wheels, particularly if we've got wheel fairings or indeed if we've got a retractable undercarriage wheel fairings for example, pool can very, very quickly filled with mud with water with slash with grass. Sometimes for some aircraft in the winter, it might be a good idea to remove these all being acknowledging the fact that we're probably going to get a bit more mud on the underside of the wings. But at least the wheel fairings aren't going to fill up and slowly aircraft down and prevent efficient acceleration. With retractable undercarriages, it may be necessary for us to clear out the undercarriage Bay a bit more for the same reasons as well fairings but also just to make sure that we keep the mechanism clean, it's not getting clogged up, it's not corroding. One of the other areas I think we need to look at is the pizza and static system. Particularly if we're letting ice and snow melt off. We don't want to fill these, fill the pizza and static up with any water any contaminants, because that's going to have a really detrimental impact to the way our instruments work.

Think about how you go about doing your walk around. If you're switching on your PTO heater, your landing lights and all your other lights as well. You could be draining you're already quite weakened battery from the cold weather.

One of the things I think that is most important for winter flying is to keep our aircraft as clean as possible. And the key areas for me are the canopy, the windscreen, the windows, because if we keep those absolutely spotlessly clean that is going to help stop the onset of misting. Any icing. And also a really clean windscreen or canopy is going to help us when we're landing into that low winter sun. The other areas that are really important to keep clean. There's all the bits of the airframe, but particularly the flying surfaces, because the cleaner they are, the more we're going to prevent any frost forming whilst we're flying.

In winter, it's far more likely to get water contamination in your fuel tanks. And that's probably because of condensation forming inside them. It's really, really important that you drain your fuel tanks from the sumps before every flight. And if possible, fill your fuel tanks up before you put the aircraft away for the night.

While the other thing this is important is that in the winter months, we tend to use a lot more ground equipment to help secure our aircraft. So we probably use more tie downs that we might in the in the summer months, we use chocks we might use covers all sorts of things that were attached to the aircraft to keep it safe. And you might like to consider having an additional checklists when you're doing your walk around to make sure that all of these items are removed. And we don't take anything flying with us that we need to leave on the ground.

When operating out of airfields that don't have hard surfaces where we're taxiing or taking off and landing on, it's really important to know the quality of that surface. Maybe it's worthwhile phoning the airfield that you're planning on landing at and asking a local pilot or the owner of the field. What's the surface like? It's worthwhile thinking about what the weather has been doing recently, it's quite likely if it's been raining very heavily, that the surface might be very soft. You also want to be thinking about the surfaces that you're taxiing across as well. I know from personal experience, I've taxi an aircraft out over a grass surface and the thing has decided to point itself into winter just weather cocking. That was definitely a day where I decided to go flying when the wind was not as strong and the airfield had dried out a bit.

One of the things that I think is is important when we're operating from particularly unlicensed aerodromes is if we if it's safe to do so, it's often a good idea to go on walk and check the surfaces that are we're going to taxi over and take off on before putting an aircraft anywhere near them. Because by doing that, we might start to find out where the nasty puddles are the buggy patches are all the places that we really don't want to go. Yeah,

I've definitely spent an hour and a half cleaning my aircraft after I've landed in a muddy spot on a grass airfield.

So there's some additional considerations when we're operating on a hard surface as well. So for example, snow and ice might have been cleared off the airfield. And when we come back, and we've taxidermy flown, still really important to clean the aircraft at the end of the day because there might be some contaminants on the aircraft that are going to cause corrosion, probably less in the way of mud or ice. But we still need to give the aircraft a really really good clean.

Although the cold weather might give your engine better performance is worthwhile getting the flight manual back out and considering how the different surfaces you're operating out of. Especially if that grass is wet or those contaminant like snow on the ground will affect your takeoff and landing performance.

Following on from different ways to prepare your aircraft. Let's talk about hazards. What are the potential hazards of flying with the air vents clothes and cabin heaters on during the winter?

Obviously in the winter, we want to fly and we want to stay nice and comfortable and nice and warm and enjoy our flight But one of the hazards of keeping the air vents closed in the cabin heater on is carbon monoxide. Now we can mitigate against this by using a carbon monoxide detector in the cockpit. And that's going to alert us to any increased levels of carbon monoxide and allow us to take appropriate action in good time to stop the effects of carbon monoxide to us or our passengers.

It's well worth though considering where we put this carbon monoxide detector. I'm aware that there's now some headsets that have a carbon monoxide detector built into them sounds like a great idea to me. But if we're just carrying a carry on carbon monoxide detector are available from your local hardware store for not very much money. We want to know when's it gonna go off? What does it sound like? And what action are we going to take if it does go off? As part of your walk around, it might be really prudent to have a good look at the cabin heater on your aircraft. If your cabin heater is a shroud wrapped around your exhaust, that's a prime candidate for getting carbon monoxide and exhaust fumes into your cabin. When you turn the cabin heater on. It's worthwhile having a really good look at this checking for any cracks in the exhaust were visible and cracks in the heater shroud itself.

Thanks both and as much of the community are aware the CAA is currently doing a lot of work on active carbon monoxide detectors. You can listen to our latest podcasts on the topic and guidance for pilots on flying with an active carbon monoxide detector on board general aviation aircraft can be found on the CAA website and in the podcast notes. And what are some of the potential difficulties that pilots would need to consider towards the end of the day?

I think for me, one of the biggest risks at the end of the day is the low sun that we can get in the winter months, and landing into that can be really quite hazardous. So one of the things that I've recommended to consider is, could you potentially land a little bit earlier before the sun gets too low? Or if we find ourselves in a situation where the sun has got too low? Could we wait for another five minutes take into account, you know the limitations of night. And coupled with that low sun, of course, is Night is coming. If you don't have a night rating, you might want to be thinking about diverting to another airfield that's close by. And I think having that plan B diver option is a really important tool to have in the toolbox. But if we are going to divert, I think it's really important to make sure that we've got enough equipment on board so that once we've landed, we ourselves can stay nice and warm. We've got a way of getting home, but also we can safely Park the aircraft, particularly if we've got any adverse weather coming in the next few days.

For more information on night flying our tutor particle has more detail on the hazards around flying at night. And if you are flying at night, make sure you have a night rating.

Those are great resources Marnie. But it's also worthwhile thinking now that winters here, why don't you go and get a knight rating, it's certainly dark enough to go and do so. I think all of this serves to not discourage you from flying in the winter. In fact, quite the opposite. But just think about the potential threats that do exist in winter.

I'd agree with that. Joe, some of the some of the best flights I've ever had have been in the winter months. There's some spectacular conditions, spectacular scenery to have a look at. And you'll have a really, really good time.

Thank you both so much for your time today. And just to say all of the safety resources mentioned in this podcast can be found in the notes. If you have any comments or questions and either this podcast or if there's a topic you'd like us to cover, and please do get in touch with us at ga podcast@caa.co.uk. Thank you so much for listening

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