The Standardised European Rules of the Air (SERA) say that you cannot fly lower than 500’ Above Ground Level or closer than 500’ to any person, vessel, vehicle or structure unless you are taking off or landing. The CAA permits an exception to this in the UK to allow gliders to fly closer and lower than this if they are hill soaring. We have enjoyed this privilege for years and take it for granted that it will continue. Unfortunately there are rumblings that it could be reviewed and revoked.

The AAIB recently interviewed the BGA while investigating a glider crash. The investigation is still under way and the BGA won’t mention any of the details until the report is published, so the rest of what I say is basically conjecture. The accident being investigated might have been the seriously injured 15 year old visiting Eden Soaring in August. This may have involved hill soaring, cloud, and overspeeding. Ridge sites like ours often attract expeditions, or increasingly, pilots visiting on their own, so another issue to add to the list is the supervision of visiting pilots, especially young ones.

The conversation between the AAIB and the BGA included some discussion of the 500’ exemption and how close gliders come to the ground and people while ridge soaring. Videos posted on social media indicate that the clearances are often quite small. The AAIB may have concluded that accidents could be prevented if the exemption to the 500’ rule was revoked and may ask the CAA to review it. This would be a serious blow to our club.

The main reasons for getting low on the hill are-

Crossing a gap.

Pushing forward to a new ridge line.

Weakening wind and lift.

Using the stronger lift near the surface to go faster.

We have limited control over the first 3, but the fourth is definitely a choice. When we are low and fast the risk of collision with people doing the same in the opposite direction is greatly increased, as is the risk of simply hitting an obstacle on the ground.

I expect many spectators on the hill enjoy seeing a glider fly past, but occasionally there are complaints of ‘being buzzed’ by dive bombing gliders. Very occasionally, pilots appear to be show-boating, passing people on the ridge then turning and diving on them again. Complaints, or even worse, videos on-line showing this will not do our cause any good. But in reality, how close are we actually getting to people on the hill?

It’s probably something to do with human perception, but ‘500 feet’ has always seemed to me to have an elastic quality to it. It seems to be quite a lot when measured vertically, but not very much at all horizontally. Being 500’ above the airfield is loads of height, but 150 metres away from the field is hardly anything. I suspect that members of the public on a hill are not very good at judging distances, and they might feel that a glider whizzing past 150 metres away is flipping close. An enthusiastic glider pilot might think 2 standard class wingspans, ie 30 metres / 100 feet  horizontally or vertically is plenty, and for safety they ought to pile on some extra speed. If you have the option to do so, giving a bit of extra clearance to people on the hill would be good airmanship.

Words from our CFI Duncan Stewart
Hill Soaring, Minimum Solo Ages and Supervision