RogerBW's Blog

I've now done a Flightgear-simulated tour at "every" airport in the United Kingdom.

Of course, "every" is a slippery term. The UK AIP lists all airports open to the public, but all sorts of small farm and private strips aren't in there. Meanwhile, the scenery file I'm using is a few years old; it includes some airfields which have since closed (such as EGSE Ipswich, now the Ravenswood housing estate in the real world), while it's missing quite a few small strips that do still exist. In the end I decided just to go with what was in the scenery file.

The airports and navaids and so on are stored in a format that is… well, not exactly easily-parsed, but I've had years of practice from when I was using X-Plane. The first step in getting back into this thing was to write a program to do that parsing and dump the results into an SQLite database, so I can easily run a query to find each airfield within a given lat/long box. (Then, since the box includes the Channel Islands, crop out the ones in France.)

So that gave me a list of 333 airfields. The next question was the order in which to visit them. Well, that's a standard sort of problem, isn't it? Travelling Salesman, in fact. And it turns out that there are standard services for solving such problems (including NEOS), and standard formats for submitting them in. So, since I already had a bunch of lats and longs, I built a matrix of distances in the right style (good old Geo::Ellipsoid makes this stuff trivial), submitted them to NEOS, and in a few seconds got back an ordered list. Done! Which gave me a circuit:

At that point, all I needed to do was choose a starting airfield (naturally EGTB Wycombe Air Park, the one nearest to me) and direction. And start flying… What this meant, of course, was that I mostly did short hops, so much more of my time was spent in takeoffs and landings than in cruises. (Except around the Scottish islands.)

My aircraft for this trip was a Cessna 337 – decent short-field capability, but light and responsive, with a usefully high cruising speed for the longer legs. (The shortest runway I had to use was, as it turned out, at the end of the second leg; EGLT Ascot Heliport, 230 metres long. Very slow approach to minimise the energy that needs to be shed through the brakes, and full flaps for takeoff…) Piston engines, not turbines, but I wasn't going high enough for that to be a problem.

Most of this was done under visual flight rules, which ended up giving me a hierarchy of ways to find an airfield:

• Is there a radio beacon actually on the field, or very near it? OK, I simply aim for that, making allowance for high ground, excluded areas, and so on.

• Failing that, is there a major obvious terrain feature nearby? A junction of rivers, a steep hill, a large lake, or a distinctive shape of forest or built-up area? I'll follow the terrain, perhaps flying along a road or a valley. For example, here's my leg from EGAL Langford Lodge to EGAB Enniskillen: red is the straight line from airfield to airfield, while black is the route I actually flew. Terrain height overlay is from SRTM data.

• Failing that, is there a VOR reasonably nearby, preferably a VOR-DME? Then I'll fly along the radial until I get to about the right distance. (But I don't have good data on magnetic variation and this led me slightly astray a few times.)

• Worst case, I put my moving map into aircraft-tracking mode, so that I have an arrow showing just where I virtually am, and use that for navigation. Yeah, in the real world I'd have a GPS receiver and I could do exactly this for every hop. But it feels too easy.

Once the field is in sight, of course, one enters the traffic pattern, circles and lands.

Mostly I flew during the day, but there were occasional legs where I tried to beat the sunset. On approach to Lasham, near Basingstoke:

And later I was thinking about getting out of Lamb Holm, off Orkney, but it was just too murky.

Shipping traffic is generated automatically. Once in a while it clumps together. (Off the Cornish coast.)

And sometimes it gets a little confused. (Near Aithsetter on Shetland.)

Welsh coast near RAF Valley, Llanfihangel yn Nhowyn in the foreground.

Most of the scenery is generic, but once in a while someone's put in a distinctive object or two. Here, of course, I'm over Belfast.

I don't know how accurate the wind farm placements are, but they're handy for working out which way the wind is actually blowing… (North of Campbeltown on the Kintyre Peninsula.)

Weather closing in over the Western Isles. (Little Minch.)

Um. I don't think so? In the real world there is a lighthouse there ("Taigh-solais Eilean Glas"), so perhaps that tripped some automated "tall structure" test…

Foula emerges from the mist.

Climbing out of some pleasingly bumpy terrain near Loch Insh.

On the way south: Eigg, and Rùm behind it.

Following the valleys: Lock Eck, towards the Firth of Clyde. (Gareloch is two valleys to the left.)

Following a different valley: Windermere, about to cross Ambleside and Waterhead.

On approach to Glasgow Airport (as distinct from the superfluous Prestwick).

On the way in to Edinburgh, with the Queensferry Crossing, Forth Road Bridge and Forth Bridge all visible.

A lumpy bit near Loch Leven.

Landed at Leuchars.

Over Morecambe Bay, picking Barrow-in-Furness out of the haze.

Blackpool Tower and a generic Ferris wheel.

One of the few lumpy bits in England. (Actually, that's cheating: I'm in Shropshire here, but the lumps are all across the border in Powys.)

An unexpected rainbow while passing Huddersfield.

So much of southern English terrain is like this. Varied, sure, and you can find your way by the roads and the shapes of the woodland, but it's so flat. (Near Market Weighton, outside Hull.) I knew this from maps, but looking at it makes it much more obvious.

In an upgrade since I last had much to do with this software, runways are not necessarily modelled as dead smooth. (Former RAF Sandtoft.)

Sunset can be very sudden in Lincolnshire. But ILS can get you home. (RAF Scampton.)

Nearly home again: the M40 running up the Chiltern escarpment.

The Wilstone reservoir, a useful landmark for lining up on runway 25 at Halton.

Nearly back to base! Wycombe in the Wye Valley, about to turn right to line up for the Air Park.

Total flying time was about 45 hours, with 5,861 nautical miles covered (roughly; sometimes I didn't have the logger running at takeoff, and sometimes I started it before I taxied out to the runway); the optimal solution was 4,407 miles, but that would be straight lines from airfield to airfield, and at the very least I had to line up with runways.

I've now got quite familiar with this simulated Cessna. Time to do the same thing again with a different aircraft somewhere else…