I was interested in this accident due to an incident I had experienced coming out of Perpignan, with the Mistral blowing down the Narbonne valley. I had an out, but I did get a fright when it became very apparent my wonderful Bonanza was not going to clear a ridge. I had a right turn available which got me out of a lot of trouble but I still remember the windshield full of mountain and thinking this is not going to happen.
He had completed a previous sightseeing trip but had climbed out and circled up to ridge height, some 11800, then flew the ridges. On the accident flight he was at 85knots. At high altitudes the Bonanza will climb over 700 fpm but only after you get to 110 knots IAS. Best climb. That is an underlying problem with a Bonanza in the mountains, they don’t perform well at low speeds or to put it another way they don’t like to fly slow up there at altitude.
I do not think this pilot registered that on his first flight. Also he only bought it in January 2020. I think the first flight may have been lulled into thinking the airplane had more performance than it really did because he was always able to put the nose down and go faster when he needed to. On the last flight that wasn’t an option.
BeechBaby wrote:
On the accident flight he was at 85knots
85 knots TAS, his IAS would have been about 75 or lower – even worse for his rate of climb. (ADS-B says 85-90 knots, but he had a ~10kt tailwind, so his IAS was probably below 70 for the last couple of minutes, and it would take very little bank angle to stall).
I also think at that stage when really running out of options he may have been looking for somewhere to put it, hence the flap. Problem when you run out of road, you run out of road…
@Beechbaby, are you sure it was the Mistral you suffered coming out of Perpignan and not the Tramontane which is far more usual and stronger coming down the valley?
These cheesy FAA vintage films are quite entertaining and paint a golden age of general aviation. Interesting the film doesn’t talk about leaning the engine for best power at high density altitude, but it is quite a good observer of psychology. The visual cues of mountain flying require training, and it is quite easy to not assess correctly whether your flight path will, or will not cross a ridge safely. Sparky Imeson’s Mountain Flying Bible is worth investing in if you can’t get some instruction.
gallois wrote:
are you sure it was the Mistral you suffered coming out of Perpignan and not the Tramontane
Yes it may well have been. We had been stuck at Perpignan for a couple of days due dreadful UK weather. Then the wind got up which had been well predicted. From memory I think the ATO called it Mistral but you will be correct if it is known locally by another name. They did advise that I fly up the coast to Narbonne, then tarck the valley, but…..I erred.
Switching on synth vision and/or profile view in ForeFlight would have told the pilot if he could make it or not. I guess his first flight lulled him into a sense of complacency. Never a good thing in aviation, even less so in the mountains.
BeechBaby wrote:
At high altitudes the Bonanza will climb over 700 fpm but only after you get to 110 knots IAS. Best climb. That is an underlying problem with a Bonanza in the mountains, they don’t perform well at low speeds or to put it another way they don’t like to fly slow up there at altitude.
The same impression when I flew the Mooney, for climbs at 10kft she does get similar numbers: 600fpm at +110ias using proper climb technique (WOT, max RPM & Mix on target EGT) and yes anything bellow 90ias you are just stuck in the glue, not the best numbers for valley/terrain flying, you get 5% gradient and +2000ft turn diameter? for all practical purposes when flying at 500ft agl vertically/laterally near terrain, it’s better to assume that climb/turn performance is simply horizontal quasi-straight line in 2D geometry, at best 3 deg above the horizon 
That kind of mountain flying in Mooney is way less fun than in Jodels/Cubs which people generally use for mountain flying training, in the latter you get 500fpm at 50ias at oxygen levels (10% gradient and 500ft turn radius), with those numbers one can easily afford sticking them very close to terrain, there is also the +300% increase from DA in takeoff/landing rolls, non-event if your sea level ground roll is 300ft but needs lot of calcs when sea level ground roll is 1200ft…
Ibra wrote:
The same impression when I flew the Mooney
And to quote a very British actor, Not a lot of people know that. I have lifted these graphics for another forum. I think they show WTF was he doing there. Some chatter about looking to pictures of waterfalls, not understanding that the terrain was coming at him quick.
