Free Our Data: the blog

A Guardian Technology campaign for free public access to data about the UK and its citizens


In today’s Guardian: the problem with route data for glider pilots

Today in the Guardian, with Access to data needs to take off, we look at the slightly unusual (in the context of this campaign) case of glider pilots, in particular, and the hassles that they have in trying to load flight data, in particular about where they may and may not fly.

The wrinkle being that the data is available – but not in a convenient machine-readable format that they could load into their GPS-based systems. And responsibility for deciding whether to do that is split between the Civil Aviation Authority – which is a government-appointed regulator – and National Air Traffic Services, a privatised organisation in which the government is the largest minority shareholder, along with commercial airlines and staff.

The point being, if you want someone to do something that would streamline things, where do you press?

Britain must love flying. How else to explain the fact that the space over the north of London is, as Andrew Watson puts it, “one of the most complicated bits of three-dimensional airspace on the planet”? And as the spokesman for National Air Traffic Services (Nats), which looks after air traffic control for commercial services, notes, there’s also the south of England, home to commercial airports such as Heathrow, “executive” airports such as Biggin Hill and Farnborough, and 60-odd other airports used by pilots of light aircraft, parachutists, hang-gliders and gliders. It’s very, very busy.

But as Watson, a glider pilot, points out, that busy-ness leads to a peculiar conflict over data. Specifically, useful access to data about where you may and may not fly in the UK. And with about 10,000 glider pilots and 3,000 gliders in the UK making some 500,000 flights a year and able to range across the country during a single flight – that access to data matters.

The Civil Aviation Authority (CAA) sets the rules about who can fly where. As Watson explains: “The UK is covered by a three-dimensional pattern of airspace into which various kinds of aircraft may or may not be allowed to enter.” All pilots must carry a chart showing that 3D space if they fly more than five miles from their airfield. (In practice, they all carry the authoritative CAA chart, published annually.)

That might seem straightforward – except that the boundaries can change from week to week or even day to day. That means pilots must check the CAA and Nats websites for the “Notices to Airmen” (or Notams, which presumably apply to female pilots too) about temporary airspace restrictions.

What Watson finds perplexing is that though you need to know those airspace “boundaries” – which are unrelated to commercial mapping data – the CAA does not publish machine-readable versions.

It’s a fiendishly complex situation, though what’s really puzzling is why NATS and the CAA, which would benefit from glider (and other private) pilots being able to get this data easily into their machines (without the possibility of transcription errors), preventing dozens of intrusions into controlled airspace every year, don’t do it.

Then again, it’s a funny world, flying. As I learnt while researching it, Nats and the CAA don’t accept GPS as a navigation device. Why? “Because it’s intentionally degraded,” I was told (by Nats). That is, your position isn’t perfectly accurate. But only to 10m, surely? Or even 100m? Is that really going to make all the difference when you’re thousands of feet (or metres) up?

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