Heat Wave Thunderstorm

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Antoine
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Heat Wave Thunderstorm

Post by Antoine »

It was 21:56 local time in Geneva, less than two hours ago,
I shut down the engine of my faithful Galatea and let out a huge scream of satisfaction.
The friendly marshaller waved a welcome sign.
His yellow van parked next to the open hangar doors, he waited for me to do the tidy-up and deboard.
He had plenty of time - the little Extra 400 was the only aircraft to land in the last 40 minutes or so.
But wait! This is the end of the story. A story I will remember...

It started with my usual weather briefing: METAR/TAF, Windy and Meteoblue.
I expected VMC on departure from the island and PROB30 thunderstorms in Geneva.
Except this was no usual summer day. The heat wave that was turning Europe into Arizona was in its third day and the skies were full of highly convective stuff that was waiting for an excuse to blow up. My island hideaway in the Atlantic was preserved from ungodly temperatures, so I kind of underestimated the threat.

I took off late in the afternoon for comfort, despite knowing that it would be a dark night, no moon...
I had expected to land in Geneva around 2115, early enough to not have the additional challenge of darkness.

As soon as I was cruising at FL190, I felt an urge and started playing with the weather radar.
The first hour of flight was uneventful - made a few pics of a CB that was developing and its radar signature on the G500.
In retrospect I believe there was some kind of instinctive discomfort:
I was monitoring the METAR of Geneva and it was changing at a rapid rate. Very unusual.
Weather was degrading and the Geneva ATIS robot voice was now mentioning an imminent thunderstorm.

The Honeywell RDR2000 weather radar picked up the growth of this CB line very accurately from an amazing 110 NM.
The flight plan was taking me straight into it, so I started to examine alternatives and prepare a strategy.
I had a major trump in my game: Geneva is my playground and I know the mountains very well, so situational awareness was no problem.
This knowledge helped me predict the shape of what would come next, except it came with such brutal power that I must admit it became scary.
Another trump was a lot of fuel on board.
And the third was my glass cockpit - it paid for itself and then some in the next minutes.

The IFR arrival into Geneva from the west is via the french city of Lyon, about 100 NM south so your flight path looks like a golf club.
The CBs developed right in the small branch of the golf club.

I considered finding a hole, passing to the east and then doing a funky arrival, but dismissed the idea. It was still before sunset and I could see clear skies to the north of this huge black wall. Only problem it was a 90 degree diversion in very very busy airspace!
I thought "ATC are gonna kill me" as I called: "N121AG request immediate heading north to avoid, and assistance with landing".
ATC took a 2 second "think pause" and switched to "how can I help you" mode.
The weather situation was degrading at a very unusual pace.
I now could hear several airliner crews requesting to hold here and there. So I asked ATC to paint me a picture of what they knew.
It proved very helpful as I mentally placed the information on the map that was fully zoomed on the panel mounted iPad.
The storm had now hit the airport with its full might. Pouring rain, heavy winds, no landings, no take-offs. I could hear one airliner after the other saying they were diverting. It was only once I found myself alone on final that I realized they had all diverted. ALL of them! Yikes!

I developed a plan with razor-sharp input form ATC.
The storm was moving north-eastbound, making the ILS 22 a no go for a long time.
I decided to wait it out and then get creative as soon as the storm would have freed-up enough of the final.
Airliners won't do that but a SEP can certainly intercept the ILS a couple of miles out.
As I was holding, the engine gracefully let me set it to lean of peak - the new mags and harness worked perfectly and fuel burn was down to about 12 GPH. I had four hours of fuel left and so I decided that plan B would only be developed if plan A failed.

Doing the racetracks near the CB was downright scary. It was now dark, and the core of the storm was glowing like that evil mountain in Lord of the Rings! It was a huge and extremely powerful CB. This photo was taken while holding.
Capture d’écran 2019-07-26 à 00.41.01.png
I felt uncomfortable and tweaked my holding patterns further away.
Finally, ATC called: the airliner that had been waiting it out had just departed and the rain was less intense. At least on the airport.
In reality, while sweeping away, the storm was rapidly gaining size and power and I could now see enormous lightning bolts in all directions.
If you look at the radar path you will see how my flight path around the storm was facetted - the a succession of heading changes.

I needed to beat the storm on its north-eastbound route and then turn back and land.
Waiting and flying behind this specific CB was out of the question because there was a whole lot of them behind it.
Capture d’écran 2019-07-26 à 00.30.39.png

I requested lower and it was challenging, this area is full of high mountains and the only safe place is Lake Geneva. So ATC was reluctant to let me do what I wanted. Fortunately ceilings were good - 5000 ft and as soon as I was low enough I knew that the only remaining threat was lightning. My God, the sky was full of it, in all directions.
I tried to make a video of the fireworks, but my iPhone stubbornly kept using its flash, so it failed.

ATC asked me if I could see the airport and I said I think so. Seconds later they switched the runway lights to max intensity and it popped out like a Christmas tree.

I loaded the visual 22 approach in the GTN750 (thanks Garmin!) and that was all the help I needed to intercept the perfect glide.

For once, Tower did not ask me to keep my speed up so I indulged in a 140 KIAS approach and enjoyed the stunning view...
There was a quartering tailwind but Galatea (that's my Extra's name) had decided to be a good plane all the way, and this flight ended in a beautiful kiss landing...
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ememic99
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Re: Heat Wave Thunderstorm

Post by ememic99 »

Thanks for sharing experience. In similar conditions last Sunday, I decided to postpone my flight to Monday morning because it was just short 45 min hop from Adriatic Sea inland and it didn't make sense to depart and them immediately hold for storm to pass.
Antoine
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Re: Heat Wave Thunderstorm

Post by Antoine »

Thank you guys.

Emir, you certainly made a wise decision.
In my case it was a much longer flight (400 NM) and believe it or not, based purely on the weather forecast, I had decided to pull it ahead flight to last night because the forecast was for a CB line sweeping France today (actually right now) topping out much higher than my AC's FL250 ceiling. The forecast did not show any major convective activity for last night and CB PROB30 sounded reasonable.
After a night's rest I must admit I should have known better. The heat wave, high mountains and large Lake Geneva make a very convective cocktail... Typically all hell breaks loose after sunset and forecast or not, I should have expected it... Call it the island syndrome...

I'd like to add to the story above that one reason the airliners had to divert is that they were low on fuel and could simply not afford to wait it out. First time I realized how tight their fuel is calculated. They were mostly EasyJets btw.
Another is probably that their airline procedures do not allow them the dodging, so they would have had a very long wait (over an hour) with uncertain outcome.

I had the opposite problem: Geneva is closed to private traffic after 2200 local. I landed only a few minutes before but just as I decided to give it a shot, ATC warned me that I would have to divert if I could not make it before the deadline.
I dismissed the discussion, but my intention was to declare an emergency if they would really deny me landing to safety on a fully operational airport for purely administrative reasons.
Heck at one point, after flying so much to the north I even considered asking them to re-open the Swiss Air Force Payerne air base for me in case things did not develop as planned and I could not turn back!
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Re: Heat Wave Thunderstorm

Post by ememic99 »

Similar chain of events here but much easier decision. TS was forecasted to pass about 1700Z but it lasted (in departure area) until 1800Z which was closure time of departure airport LDLO. I should've known that it couldn't be so precise under these conditions but I chose to trust it, to spend more time on the beach, rather than to depart at 1200Z. So I waited until 1700Z to make my final decision. If I departed at 1800Z flying slowly along northwest bound of TS I would land at my alternate LDZA at 1845Z - 15 minutes before closing GA terminal while my destination LDVA would've been already closed at 1830Z. LDZA is H24 so I could've hold and land later if there was need but then it would be connected to hassle of transporting to main terminal. Anyway, it would be quite tight schedule of much hassle, so I decided it was not worth of it.

Actual weather 30 min after the cancelation and closing departure airport:
actual.png
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ememic99
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Re: Heat Wave Thunderstorm

Post by ememic99 »

And this is how it looked like an hour and half earlier:
actual_dep.png
Antoine
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Re: Heat Wave Thunderstorm

Post by Antoine »

Well done.
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Colin
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Re: Heat Wave Thunderstorm

Post by Colin »

Antoine, does the cost of changing your plans ever figure into your decision? (My understanding is that in Europe if you change your destination under IFR you pay a hundred Euro fee.)
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ememic99
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Re: Heat Wave Thunderstorm

Post by ememic99 »

Colin wrote: Sat Jul 27, 2019 2:41 am My understanding is that in Europe if you change your destination under IFR you pay a hundred Euro fee.
No, I’m not aware of such provision. However, over 2 tons aircrafts pay airways fee to Eurocontrol and diverting causes some additional costs.
Antoine
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Re: Heat Wave Thunderstorm

Post by Antoine »

Colin sorry for late reply. This is definitely not the case. I do it every time it makes sense. Especially french ATC are very friendly - unless they confronted with a thick accent, in which case they tend to scale down service to a very formalistic level.
I have a new Thunderstorm story to tell. See next post :)
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