Andy Sanderson reports on his memorable glider flight around the London TMA
Ever since I did my first 500km flight in my old Vega 890, I have been looking for new and interesting challenges. One of the things that had never been achieved from Essex & Suffolk GC, which is situated at Wormingford, near the Essex coast just northwest of Colchester, was a circumnavigation of the London TMA. Some time ago in 2000, I became determined to achieve this flight, and really began to make concrete plans to do the flight in 2001.
In 2001, I made two failed attempts. The first flight taught me a lot of things I had not anticipated about the necessary wind conditions, and I only made it as far as Parham. Having set off on this first attempt, my main concern was crossing the Thames, which I had never done before, and I reached it near Canvey Island. Looking across from 3500 feet I could see that the crossing was nowhere near as daunting as some people had led me to believe. One of our club members had previously made an out and return to Challock, so I had a good idea that it was possible, and when I got there I found that in fact the river at that point is not much wider than a few kilometres and the worst problem, rather than the actual width of the river, is that on the both sides some of the potential landing areas are not very suitable, such as the marshes.
Having crossed the Thames, arriving at the other side at about 2000 feet, it was fairly straightforward to find lift to get me to Challock, which I had declared as my first turning point. However, the lift seemed to be unreliable in Kent and as I went towards Challock I lost height and arrived there at barely circuit height. It took me a good 20 minutes of scratching, having dumped water ballast over the caravans, to turn a scruffy bit of zero sink into a 4-knotter that took me to cloudbase at about 4000 feet.
At this point, I thought everything would now be easy, as I headed off down towards Ringmer under some fantastic looking clouds, and confidently pushed southwards. But then I suddenly popped out into completely clear air, on the other side of what I soon realised was a sea breeze front that had been attempting to push me into the Gatwick airspace. Once out on the seaward side of the front, and unable to get back under the front which was now marching across Gatwick, things took a whole turn for the worse, as, under an inversion caused by the cold sea air, I was hedge hopping over some very small fields towards Ringmer, and after a titanic struggle, mostly below 2000 feet, only just made it to Parham. I had hoped that if I could squeak back inland again towards Lasham, things might improve, but arriving with only about 400 feet to spare, I did what little I could of a circuit and landed at the far end of the runway. The natives were very friendly and I had plenty of time while waiting for my retrieve to visit the local hostelry, which the club has thoughtfully organised to be only a short walk from the club gate.
For my second attempt, I decided to leave out Challock as a turning point and declared Wormingford – Ringmer – Lasham – Bedford Bridge – Wormingford. If travelled in a straight line, the task would go within airspace even at 3000 feet, so the although the declared task distance is 411.38km, in practice it is probably nearer 420km, not allowing for further diversions for better weather or higher airspace. Having learnt of the potential for sea breeze problems, requiring a stronger northerly component to the wind, and not wanting to cross the Thames late in the day into such a wind, I resolved again to go clockwise – indeed, going anti-clockwise may seldom be realistic from Wormingford. This time the strategy worked perfectly – almost. I got round as far as Alton with no trouble at all. However, towards the west the sky had gone totally blue, and it was one of those days when blue really did mean blue, without a single hint of a haze cap visible anywhere in the sky. This, of course, slowed me to a crawl and it looked as though I was going to land out at Lasham. However, every time I thought was going to land out, I seemed to find another blue thermal and I managed to get up as far as Reading, where I had a very low point of less than 600 feet over the recently finished Reading Rock Festival, managed to get away again, then looked as though I was going to land out successively at Booker, Dunstable, and Gransden Lodge. Unfortunately, due to the slowness of my progress after Alton, the day was fast running out and although I now had a tailwind helping me back towards Wormingford, I got low southeast of Cambridge and eventually landed out at Hildersham at about half past seven in the evening, after 200km in the blue, about 40km short. Nevertheless, the attempt was far more successful than the first one, and it made me realise that such a task was definitely possible, given the right conditions.
Needless to say, from that point on I waited and waited for the right conditions: a north or northwesterly breeze of about 12 to 15 knots, a nice ridge of high pressure building from the west, and a weekend or a day when I could get away from work. Typically, very few days like this came along, but finally things started looking good towards the end of June 2002 with the Azores High building nicely across the country, and staying in the right place for long enough for me to choose a suitable day.
On the day of Friday the 28th of June 2002, having previously prepared everything down to the last minor detail the night before, I went out very early to the airfield. The sky was blue and the air had the right feel about it, fresh and cool. I rigged and watered the glider, made sure that everything was ready for the flight, then took the first launch of the day.
I stayed locally for about 20 minutes before deciding to start. There was some fantastic streeting from the north, and the clouds were already quite large. Comments had been made earlier that perhaps the day had started too early, but as the forecast was for higher pressure to the west I hoped that, as I went around the task and the pressure built from the west towards me, perhaps I would not have too much trouble with spreadout. Heading south with a significant tailwind it took me no time at all to reach Southend, and I arrived at approximately 3200 feet over the coast. Ideally, I would have liked to have been exactly at the top of the available airspace, 3500 feet above sea level. But there appeared to be no suitable lift nearby, so I took the plunge and darted across the Thames in the direction of Maidstone.
As luck would have it, when I arrived at the southern coast of the Thames, I found a 4-knot thermal that took me straight back to 3500 feet, which was reassuring, and proceeded with no difficulty over Maidstone and Staplehurst towards Hawkhurst, where I emerged into the FL55 part of the Worthing Control Area, and could then increase altitude to cloudbase which was approximately 4000 feet. From there, I tracked almost exactly down the edge of the TMA towards Ringmer. I rounded Ringmer and headed west setting my GPS destination to Parham, as I knew that it was a good place to land. Flying between 2000 and 4000 feet, I skirted the northern tip of Brighton. There was a sea breeze front lying exactly along the coast at Brighton and although I was about a mile north of it I was very tempted to go over to investigate the lift on it. However, common sense dictated that I should not go downwind unless necessary so I continued west towards Goodwood racecourse as I passed to the south of Parham. I reset my GPS destination to Lasham, and headed northwest over Midhurst and Alton.
By this time the sky was still reasonably good, although there was much more cloud and spreadout than I had forecast, but still with some good four to six knot thermals. At Lasham I found a thermal directly over the airfield. I was not 100% convinced that I had rounded the turning point, so just to make sure I went round the clubhouse again and headed north towards Basingstoke. As I headed almost due north for the first half of the third leg, conditions became much more difficult, with six to eight-eighths cover. The strength of the thermals had also decreased to an average of two knots and flying into wind it took me a very long time to make progress northwards towards Thame and Aylesbury. By this point I was convinced that I was not going to complete the task, so I dumped my water and successively selected Booker and Dunstable as possible landing sites should I get low. I took every scrap of lift that was available, and if I needed to divert even more than 90 degrees off track I did so, simply to stay near cloudbase. There were a number of crop-free fields that could possibly have been used to land in, but none of them looked particularly tempting and I resolved to stay as high as possible. There were some very tricky times where I simply did not know what to do, and occasionally I had to park under a very scruffy bit of lift just to wait and see what was developing ahead.
Eventually, I managed to get round Bedford Bridge and headed east towards Gransden Lodge, where I knew it was possible to land and receive a friendly reception, but in trying to get within range of Gransden I had to cross an enormous grey hole within which there was no lift whatsoever. Late in the day, down to 2000 feet and already feeling low, in both senses of the word, I found another scruffy bit of zero sink which I parked in for at least 20 minutes while I watched the sky painfully slowly develop far ahead and also slightly behind me. I then needed to backtrack about a mile towards St. Neots to find the only real lift that was available nearby, and that gave me the extra 1000 feet I needed to cross the next big gap towards Cambridge South.
Once there, I easily got back to 4000 feet again in some very good lift, and headed east, skirting the Stansted airspace to the south. Once I was convinced that I was on final glide, and down to 3500 feet I was able to turn under the airspace and head straight for home. As I passed near Sudbury to the east at approximately 2000 feet, I realised that I could get home, but bearing in mind the recent strong lift that I had experienced, I resolved not to overdo the speed on the final glide until I was 100% sure that I could make it home. As luck would have it, there was no sink on the final glide – if anything, there was further lift. I crossed the runway at 120 knots at about 100 feet, pulling up and round to the left for a landing on runway 27, completing the task in 6 hours 54 minutes, at a very slow average speed of just less than 60kph. The time was approximately 5:45, and at the club everybody except one person had already gone home! Luckily two others had just turned up to pitch camp for the weekend, and between the four of us we derigged the glider and retired to the clubhouse.
Thus, I finally proved the task was possible. I believe that without big wings the task would be quite difficult from anywhere other than Wormingford (or possibly Ridgewell, Rattlesden, Wattisham or Gransden Lodge), as the necessity for a northerly component to the wind means that unless the day is very long (or the wings are even longer!), the Thames should ideally be crossed fairly early in the day, and the south coast should be negotiated before any sea breeze makes it inland. The remainder of the flight, however, should be easy on any good soaring day. Also, given better conditions inland, I am sure the task could be done much more quickly than 60kph. As well as the exhilaration of having completed the task, one of my first thoughts was “well, what next?”. I’m now considering that perhaps it would be nice to combine another circumnavigation of the TMA with a 500km declaration, but as I already consider that the 411km was already more difficult than the average 500km flight I suspect that the combination may stretch my (and my glider’s) abilities. However, that will probably not stop me trying.
If anybody else has recently completed a circumnavigation of the London TMA I would be interested hear from them so that we can swap notes. Above all, despite (or perhaps because of) the weather not turning out as good as forecast, it was a very enjoyable and satisfying flight.
Andy Sanderson, Vega “AS” (was “890”)