One my latest flying tour returning from the Swiss and French Alpine valleys dappled with summer sunshine and strange accents on air traffic control radio, I was very lucky to be faster than a rapidly expanding Cumulo-Nimbus storm cell just north of Paris…..
I was flying back a couple of weeks ago in the middle of the hottest summer we have had in Europe for decades with temperatures exceeding 38C in some places… The weather conditions were just right for the damp air coming from the west, gathering moisture over the Atlantic and the English Channel to form the usual summer thunderstorms on the western plains of France.
Unusually for me, I was not talking to anyone on the radio whilst flying, just listening out on Paris Information. I was looking at the horizon slowly disappearing into haze with light drizzle and virga in places, which could be seen clearly defined from clouds. I wondered whether I would be able to continue the 100 miles further to my destination of Le Touquet before 8 pm local time when they closed for the evening.
Suddenly my ears tingled on hearing an English helicopter pilot call out to say he was diverting due to heavy rain and lightening strikes nearby. The tingling was not due to the language but due to the lightening strikes. The embedded CB was moving at 20 knots from west to east directly into my flight path. I was flying at a leisurely 90 knots. The decision was quickly made to turn west, southwest so as to go behind the storm cell staying clear by about 10 to 15 miles. Calling Paris Info, introductions made, intentions clarified, potential diversion plan notified, I was given a squawk code and told that local weather conditions were perfect for a summer evening.
I heard some of the lightening crackle on the radio as it swamped the electro-magnetic spectrum with immense power and light. Fortunately I was well away from danger, going further away from it. In less than 10 minutes of deciding to divert from my flight path to avoid the haze and drizzle, I realised I was being overtaken by the rapidly expanding CB, engorging itself on the heat over the huge agricultural plains in France. My plan to divert to Beauvais airport, about 30 miles north of Le Bourget, Paris was quickly cancelled as I received the weather update from Paris Info. Beauvais was under another storm cell with hailstones and lightening strikes.
I tracked further south towards Paris and could see the city spread out under the early evening sunshine with the Eiffel Tower glinting cheekily. The joystick was snatched out of my hand and only being strapped very tightly in the seat prevented my head and shoulders being dashed into the overhead section of the wing spars. The turbulence was totally unexpected so far away from the edge of the storm. My instant reaction was to close the throttle and allow the aircraft to be thrown about. The Pipistrel Alpha rode the rough air very well and impressed me with its stability in the turbulence.
At the same time, Paris Info asked me to change frequency…. The conversation went something like this:-
I said “Paris, I am unable to control my height”
“confirm you are unable to control your flight?”
“don’t talk to me I am busy flying”
“do you need assistance”
“there is an airfield two miles away for you to land”
“I am not landing anywhere in this turbulence; I have never crashed with the sky, I am safer up here than trying to land in the turbulence”
“Le Bourget is available for you to land… weather is calm and CAVOK”
“I can see that; but the storm on my right is expanding rapidly so I am going to bust your space”
“you already have; please squawk 7706”
“unable due to turbulence; when able, Wilco”
“okay no problem”
After what seemed like 20 minutes (but was actually less than 10 min) of very rough air throwing me about, I came out of the boundary turbulence of the storm cell. I did a visual check of the cockpit to see if anything had broken loose and finding that everything worked and the engine was running smoothly, I continued westwards to Pontoise airport. They had been told by Paris Info about my encounter with turbulence and were awaiting my diversion.
“ah yes, Whiskey Oscar; welcome, we are waiting for you and are proud of you to handle the flight”
That voice provided much relief with such a welcoming attitude…. Helped me land smoothly on their tarmac.
Aircraft tied down, taxi out, cheap hotel, small beer, phone call home, lights out. The next morning at the airfield, quick fuel up, coffee, thank yous to all involved and happy smooth journey over the Channel back to Blighty…
Lessons learned:- summer flying is great, expect thunderstorms. Keep SkyDemon handy and updated with all databases and plates. Talk to ATC for info and to listen out and build a picture of what is happening to other aircraft. Call for diversion sooner than later. Ask for help sooner than later. Storms move at 10 to 20 knots and you can fly away faster than them. But the storm can expand very rapidly and envelope you from above and around.
I remember the view from the cockpit of a Boeing 737, many moons ago from Delhi to Mumbai when we were asked to divert more than 200 miles to avoid a summer CB which extended from 1500’ to 45000’ over the hot Indian plains… fortunately the CB in Europe are not that large.. but large enough to kill us if we venture near them.
See my flight path and that of the storm cell in the pictures… The screen shots were taken after I landed so it shows the CB over my flight path, but rest assured I was not so close to it when I was flying or I would be telling this tale…