The autumnal high pressure system gave us clear skies with a temperature inversion with smooth air. It gave us an irresistible urge to fly through the Alps on the cold, clear day over the lightly misted valleys.
We took off from Haguenau airfield north of Strasbourg on the French German border and headed south over the wide Rhine valley. I had filed a flight plan from the eastern VRP to the southern VRP in the Strasbourg CTR; but on first contact, Strasbourg Radar controller gave us instructions to route to the west of their control area. Fortunately I had the alternate route planned as well. A 3 mile wide circular turn set us on course as instructed. Thanks again to the Skydemon software, we were able to stay accurately on course, flying very close to the very tall telephone mast to the west of the Strasbourg airport.
Crossing over from the French border into Switzerland, we left the Vosges mountain range on our right flank as we headed towards the Jura Mountains, skimming over the sharp but civilised and cultivated ridges towards Grenchen airport, where I had attended a symposium on electric aircraft recently. We were instructed by Bern ATC to take a different route than the one we had planned. Not a problem as we were in super smooth air and enjoying the easy flying whilst taking photos of the approaching high Alps in the mist. Lake Neuchatel was still enjoying summer like clear air, but the inversion displayed the polluted air sitting still on the lake valley.
Flying past Fribourg, I recalled meeting my Swiss friend who has 3 Electric Alpha aircraft sitting in his hangar at Ecuvillens airport. The set up has a large solar panel array on the hangar roof, with accumulator batteries which can send electrical power into the main national grid when not required for charging aircraft and cars at the airport. The future is here !
ATC instructed us to call at Montreau on the northern bank of Lake Geneva, it was covered in low fog. We turned southeast towards Martigny and started a shallow cruise climb to 6000 to fly over the mountains, turning from dark green to rocky grey and dirty snow white. The valley started getting quite narrow with ragged rock peaks rising over our heads dwarfing us. I was very anxious about being hit by turbulent air at the confluence of the three valleys at Martigny. Fortunately there was no wind. The air temperature dropped to 1 C as we climbed to 8000 feet. This was the inversion layer of warm air sitting on top of the cold air in the valley since the previous night had been clear dark blue, giving off all the heat to the stars. The low sun had not yet reached the valley floors as we continued to fly on the sunny side of the mountains making use of the updrafts taking us up at 200 feet per minute, mile after mile as we watched with some awe and wonder at the lack of snow on the high moutains.
We made a gentle sweeping turn on the eastern side of Mont Blanc, keeping the engine warm but not over revving it. I was mindful of the true airspeed in the thin air at 12,000 feet, so as not to exceed our VNE of 130 knots. Our indicated airspeed was about 90 knots but the TAS worked out be closer to 120 knots. The air temperature was a steady 1 C due to the inversion. Normally it would have been -5 C or thereabouts.
We had lost all radio contact with ATC but that was to be expected flying below the high mountains out of radio sight from any large town. We had been asked by ATC to make contact after we turned around Mont Blanc. Some awestruck sightseeing was committed at the cost of not paying attention to accurate flying but the Pipistrel Alpha performed superbly as it was well trimmed and never felt it strain due to the altitude.
We flew around the east and south of Mont Blanc and my friend Geoff felt very proud for having climbed the mountain on foot just 4 days previously to our flight. We landed at Annemasse airport for a quick refuelling stop on our way back north.