Day 19

Through the snow to Bournemouth this morning. There were three accidents on the road as I drove down. One car was on its roof on the A303 just as it leaves the M3 at Basingstoke, and two more shunts further down the motorway. The weather is often a hazard on the roads, and it is even more so in the air.

Safely at Bournemouth I flight-planned for a trip to Evercreech, near Shepton Mallet in Somerset. The weather was potentially problematic, with a few thunderstorm (Cumolonimbus, or CB's, left) clouds and some rain around.

Pilots are particularly wary of CB's, since they are associated with severe turbulence and icing. The vertical air currents inside a CB cloud can be several thousand feet per minute.

Just for perspective, the Duchess climbs at around 1000ft per minute on two engines, and a comfortable descent would be a little less, at 500ft per minute (more than this and your ears can become uncomfortable as the pressure in the inner ear stabilises).

So flying into a CB could be quite an adventure, and assuming the wings are not ripped off due to the airframe stresses, they might come out the other side coated with a generous layer of ice, and so would lose most of their aerodynamic efficiency. Plus the effective aircraft weight would increase due to the weight of the ice, so all in all this is a situation better avoided.

With these happy thoughts in our minds, after lunch we set off and found that at 2500 ft we were able to remain clear of the clouds and steer around most of the rain. Once at Evercreech (15 minutes) I was then given a diversion to Charmouth near Lyme Regis, followed by another diversion to a town called Sturminster Newton, not far from Shaftesbury. The mental workload continues to increase, and I was on the radio to Compton Abbas airfield, Yeovil, Westlands, and Bournemouth Radar during the flight.