Safety Notes October 2023

By Brian Stewart on  October 11, 2023 17:20

Incident

As many of you will know, on Sunday 8th one of our members was seriously injured on the South face of Parlick and airlifted to hospital. We wish him a full and speedy recovery from his injuries.

As we move towards winter, it’s worth analysing in some detail how the weather may have been a significant factor. As the power of the sun to heat the ground reduces, thermal production slows and so the mixing of the layers of air stops happening and a low-level inversion can often last all day. You will often see clouds above whizzing past with little or no wind on the ground early in the day. In summer, vertical mixing of the upper and lower layers usually clears this inversion, but in winter it can lurk undetected. If this layer is below the take off, you may feel this as a sudden increase in wind speed from very light to very strong, possibly with an abrupt change in direction – a clear warning sign. However if the layer is just above take off, you may launch from what feels like a perfect breeze into a nightmare as the friction between the layers of air moving at different speeds and directions creates violent vortices. This can happen at any altitude, but if it’s close to the ground, any collapses induced may be unrecoverable before impact.

Warm southerly airflows are particularly prone to causing this effect as they produce more pronounced inversions, which is significant for our south-facing sites like Parlick and Nonts. An approaching warm front can mean warm air riding over the cooler air near the ground, which exaggerates the inversion Add in the wave influence of upwind hills (Longridge, Standedge) and you get a recipe for extreme turbulence, just where you don’t want it.

Back in the day, we used to just have the TV forecasts and shipping forecasts, so just went out when the weather man (and it was always a man back then) said the magic words ‘light to moderate’ and sometimes had a horrible experience, muttering over our beers about what might have caused it. Now we have incredibly detailed atmospheric models to predict what the wind is going to be doing at every level. The question is how to access and make use of this amazing resource. The ground level wind speeds on the Met Office site, XCWeather etc are only a starting point – if they say too strong, then it’s too strong, but if the numbers are low, it’s vital to look at the upper layers to get an idea of what is going on above our heads. This isn’t the place for an in-depth lesson on weather forecasting, and I’m not the person to do it, but here’s a few take-aways from the conditions on Sunday.

This is the RASP tephigram custom sounding for 1100 BST on Sunday 8th October for Chipping (CHP) Note the low level inversion where the air temperature increases with height and how the wind changes direction .

 

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Here’s another view of the 1100 data, provided by NOAA and analysed by Neil Charles:

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Here we can see that the wind was forecast light SE at ground level, fresh S at take off and veering to strong SW just above.

Other sources of data include Windy.com and the Windy.app, Ventusky, which have free versions that provide this data. There are many others. My advice is to find one that you can learn how to use, and visit it regularly before flying. Look at them on the days before too, see how the forecasts change. Where possible examine the different data sources (ECMWF, Met Office, NOAA, GFS etc.) – the more they agree, the more confidence you can place in the prediction.

So how do we use these data in order to make out flying safer?

We are the pilots, and we are responsible for our own decisions; there is no launch marshal or air traffic controller to make us see sense. Here are some tips:

ALWAYS check winds at higher altitudes – all year round. Don't just look at ground level winds before flying. We don't fly at ground level, so it is silly to only look at ground level winds. Even on days when there is no inversion there can often be surprisingly stronger winds at take off height or higher.

In summer you will mostly get away with only looking at ground level winds, as in summer the difference between ground and upper winds is generally not great for the reasons given above. But why not spend five minutes looking, it may save you a wasted trip to a blown out hill.

In winter you won't get away with only checking ground level winds for long. Even on days when there is little or no inversion, the difference in winter between ground level and higher level winds can be dangerously high. Add an inversion around hill hight and danger is multiplied. 

The wind speed and directions on soundings can be a little awkward and imprecise to read; however using websites like www.ventusky.com you can check the wind speed and direction of all northern England at 10m, 100m, 250m, 500m, 750m, 1000m, 1500m etc. You don't have to check every altitude, but you should check 100m, 500m (take off altitude) and 750m at say 10am, 1pm and 16pm. When you get familiar with a website or app like Ventusky you will be able to check the winds in five minutes. It is a lot quicker than recovering in a hospital bed for four months.

Using the free version of an app like Windy.app you can get a spot forecast for Parlick landing field showing the wind at all altitudes in about 60 seconds, as below:

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Neil Charles is currently developing a tool to show graphically the wind speed and direction at our sites and elsewhere. Watch this space for news

Don't use RASP for wind speed in winter. In summer time the RASP parameters “BL Avg. Wind” and “Wind at BL Top” are excellent forecasts. But in winter these parameters are often useless as the Boundary Layer is so low. If there is an inversion at 900ft then BL top will be 900ft, so “BL Avg. wind” will be an average of the wind from the ground level to 900ft – not much use when you are taking off at 1300ft.The decision to take off is every pilots personal responsibility, every pilot should be checking the weather before they fly. Don't rely on others, don't fly like sheep!

Brian Stewart and Phil Wallbank, with contributions from Gordon Rigg (DSC).

Safety Notes September 2023

By Brian Stewart on  September 19, 2023 11:30

It’s been a fairly quiet year as far as incidents go so far . . . Probably tempting fate by writing that, but I don’t believe in that nonsense, so there.

Equipment Checks

We all do these, don’t we? Daily inspection, pre-flight checks etc. One of our members received a harness with his reserve re-packed back from a well-known PG service centre. During a pre-flight check the bridle zipper was seen to be starting to open and was re-closed. This happened again at the next flight. Further checking showed a mistake in re-packing the reserve and closing the container. AFAIK this is still unresolved between the pilot and the service centre. This shows the importance of doing your own inspections and checks every time you launch. You know it makes sense.

Another recent incident involved a near-miss for a member when one set of risers became trapped inside the carabiner of the opposite riser. Fortunately, he was sufficiently aware to abort the launch before getting lifted too far, but still got dragged. The carabiners in this case were the screwgate type, not the more common twist-lock gate, which require two separate actions to unlock the gate (slide and twist). The screwgates on both carabiners had not been tightened up to lock, so were both free to open. Again, this shows how important it is to include such a check in your list if you have these carabiners. Also remember the advice about replacing carabiners every 5 years or 500 flight hours. As they are subject to repeated load cycles the alloys used in them will work-harden over time and become brittle.

Calder Valley Search and Rescue Team

Earlier this year the CVSRT got in touch to find out more about our sport and the equipment we use. It’s the eastern sites like Blackstone Edge, Nont Sarah’s and Pule that are more likely to be within their region, and it’s the recent increase in use of these sites that has brought us to their attention. They had a couple of calls from concerned members of the public reporting PGs in distress. Despite searching, including with helicopter, they found nothing but wanted to know more.

Mark Shaw, BHPA Technical Officer came up to their Mytholmroyd HQ las week and gave them a presentation about our sport which I attended, covering all aspects from speed flying to powered hang gliding. It was interesting to find how little they knew of what we do – the outsider’s view that we’re a bunch of reckless thrill-seekers wasn’t so prevalent (much more respect for us as fellow users of the outdoors) – but the realisation that we actually fly distances was quite an eye-opener for some. A useful lesson learned that our activities are not confined to specific locations. Their HQ is very impressive, and the team all turned out in their mountain rescue kit – they are a very professional organisation with 45-50 registered responders with a wealth of medical knowledge and expertise between them. One subject that we discussed at length was the issue of alerting soaring pilots to the arrival of a helimed. The MRT members all carry smoke flares – these are deployed to guide the heli to the spot and indicate wind conditions. The suggestion that one could be set off as soon as the heli was requested will be carried forward by Mark to the BHPA with a view to establishing a code of practice.

This was a very useful evening, and was great for making contact with the people who do such great work on the ground saving lives.

Tight lines, everyone

Safety Notes March 2023

By Brian Stewart on  March 6, 2023 16:43

It’s a new season, so here’s some wise words gratefully borrowed from Wayne Smith, DSC Safety Officer.

As the weather is giving opportunities to fly again, you're probably thinking it's time to end that Winter lay-off (if you haven't already). Some safety musings before you head out to try and find somewhere remotely near Parlick to park…

Equipment

· You’ve repacked your reserve, yes? Your reserve should be checked \ re-packed at regular intervals as outlined in manufacturer’s manual. In absence of this, BHPA recommends every 6 months.

· Servicing – your glider should be checked \ serviced at regular intervals as outlined in manufacturer’s manual. In absence of this, BHPA recommends every 12 months. Your harness, too – make sure the mice haven’t taken up residence in it.

· Remember your pre-flight checks

Weather

· Spring time can produce strong thermals due to cool nights and warm days.

· Be aware that turbulent air can also be caused by wind shear and marked boundary layers.

· When you arrive at the site, you’re not simply checking if the conditions are flyable – are they flyable for you? Better to be on the ground wishing you were in the air, than in the air wishing you were on the ground...

Take-off

· Try to get some ground handling in after the Winter layoff. This will help re-awaken your muscle memory and get your “feel” for your glider back.

· Be prepared to help out fellow pilots – e.g. if they’ve fluffed launch and are being dragged, grab a wing-tip to get the glider under control

· We’re all fallible - give yourself and others extra space for errors on take-off.

In the air

· Pilots in contention both turn right, unless hampered by geography, in which case…

· Give way to the pilot with the ridge on their right

· Join a thermal in the direction of rotation of pilots already established in it

· Don’t turn aggressively in thermals close to the ridge

· Monitor your position over the ridge – if drifting back, be ready to use speed-bar while you still have plenty of height to get back into ridge lift

Landing

· You checked whether your landing site is affected by lambing closures before you launched, right?

· Give yourself more height than usual over the landing site – height = time & options

· When planning a top-landing, fly the ridge first to evaluate the air you will be landing in

· You’re down! It’s been an epic first flight of the season. You’re stoked. Amazing. Now clear the landing field as quickly as possible – pack up at the side to give others room to land

Usually, there will be Club Coaches on the hill – speak to them, for they’re a lonely \ lovely bunch and will be happy to offer advice and assistance

Have a great start to the season and fly safe

Tight lines, everyone

Safety Notes August 2022

By Brian Stewart on  August 31, 2022 09:11

Base of Support.

If you’re a subscriber to Cross Country Mag, you may already have viewed their two recent Masterclass presentations by SIV and Glider Control guru Malin Lobb. They may appear on YouTube sometime, but don’t seem to be up yet, except for this excellent snippet: https://youtu.be/YofbzTJzy04

In the full masterclasses presentations, he goes into a great deal of detail about glider control in adverse situations – these alone are worth the magazine subscription I think. In this excerpt he describes the importance of your ‘base of support’ and how to use your harness to keep your body under control when your glider is trying to throw you around. Basically, maintaining your back support by carefully adjusting your harness, tucking your legs, and spreading your thighs to give you a firm base while reducing your moment of inertia (less risk of a twist).

Elsewhere in the talks he constantly refers to this, keeping your body firmly place in the harness, reducing the temptation to use your arms as levers or balancing aids. There are two main problems here:

  • ·Waving your arms around to try to maintain balance. It’s a natural thing to do when you’re trying to walk a tight rope, but your brakes are in your hands, so you are putting random brake inputs into the glider, which is a very bad idea when you are trying to rescue any departure from normal flight
  • ·Using the risers to hold on to. Again, very natural if you are on a swing, but it delays your ability to react quickly and make the accurate control inputs needed. I found this out in an earlier SIV course when I was getting collapses doing wingovers. It was Johann that spotted I was grabbing the risers, which affected my timing. It took some practice to stop doing this, as I wasn’t aware I did it at all.

Sailplanes

We sometimes share some very crowded bits of space with our neighbours from the Bowland Forest Gliding Club. Their sleek fibreglass aircraft can appear very quickly and be almost invisible head on. It shouldn’t need saying that keeping a very sharp lookout is essential whenever they are operating (and when they’re not). A recent incident was reported that one of their single-seaters came very close to a paraglider, and took avoiding action. Clearly close enough to cause a lot of concern to those who saw it.

What is really good about this incident is that rather than start up a social media debate about rights and wrongs, the pilot affected contacted me as Safety Officer. After a discussion with my BFGC counterpart (who is also a PSC member and very experienced HG and PG pilot) a meeting was arranged between the two pilots. Both were able to put their concerns to each other in a very measured and constructive way. From the sailplane pilot’s point of view, he was able to see how being so close would cause concern, while the PG pilot got an insight into just how manoeuvrable sailplanes are and how quickly they can change height and direction. As a bonus he got a flight in a sailplane and was able to see the view from the cockpit, sharing thermals with some PGs and doing the Totridge run. Sailplanes, hang gliders and paragliders have been mixing it in the Parlick bowls for decades now – it’s worth remembering that only the more experienced BFGC pilots are allowed to enter these places when there are foot-launched aircraft flying, unless they are under instruction.

They can change height and direction much more rapidly than we can, but it is always the responsibility of both pilots to avoid getting into a situation where a collision is possible, so both need to keep a sharp lookout and think further ahead when flying together due to their much higher speeds.

Safety concerns every one of us, and it’s good to know that we can have these discussions without pointing fingers, laying blame or shouting at each other. Next time you get cut up in a thermal, or think another pilot has endangered you in some way, please take time to think about it before launching into aggression or uploading your video. Every day should be a school day for all of us, we can all learn something from every event.

We’re planning a joint ‘Sharing the Sky’ event with BFGC in which we can all get together (PG, HG and sailplanes) to learn about the similarities with and differences between each other’s sports. Coming soon . . .