Peter wrote:
It is positively begging for someone to cross there at 6500ft.The IGN chart does not have TA indicated, but you can see that the high peaks are outside of that box to the east, 6500ft is fine inside the box where the TA is applicable. On the other hand the 1 millionth chart has the TA, but no indication of the high peaks and ridges, all the space is used up for TMA segment description. One might argue neither of the maps is complete and accurate.
to maybe work out what might have happened one needs to put oneself in the position of the other pilot, visiting from another country, not a local expert.Absolutely, and we all have our own biases. The Alps climb quite sharply, MSA west of Chambery is 5,500ft, east of it jumps to 15700ft. No medium hills transition bullsh*t. I tried different paths in SD, assuming the terrain data is even somewhat accurate you cannot cross the Bauges in too many places at 6500ft.
Peter wrote:
Can you really get sudden strong winds locally, when the MSLP shows almost nothing?
There was wind at FL100 from the south east, about 30kt, near Colmar, FWIW.
The MSLP corresponds with that, but only earlier on, not near the crash site.
However if you are only hundreds of feet above the terrain anyway, you don’t need much…
And if one was watching a decent VFR chart with spot elevations, one would not be anywhere remotely near 6500ft in that area anyway.
Does the TA=6500 have any relationship to the terrain? A transition altitude is just a figure where you change from a flight level to QNH, and is irrelevant to flying OCAS. I don’t know anybody who uses the TA value autonomously. Normally ATC clear you to climb or descend to an altitude or a flight level and you set the altimeter appropriately (with some debate on the details e.g. if at FL100 with a TA of 6000 and cleared to 2000ft with a QNH of 1029, would you set 1029 the moment you start the descent, or only as you cross 6000ft, etc).
I think the TA is a redherring, but the “6500” might have looked to the pilot as some kind of “MEA” figure.
Yes it can be so that the wind chart shows few in the low resolution and locally you can get a mountain wave or rotor.
I am not convinced of that scenario though. Looking at the frontal chart, I personally think it looks more like they descended just below the ceiling and then either got IMC and never saw the ridge they hit or they suffered from a white out or something similar, thinking there is nothing there but something snowy was. The picture shows where the parts ended up, not necessarily where they hit. I’ve seen similar accident pictures which most of them were the consequence of a C-FIT where the crew literally never knew what happened or, for that matter, that something happened.
Yes, Föhn is one of the more dangerous phenomena (like the Chinook in the US which probably did bring down a 737 once) but it was not very strong in that area. there were MTW’s reported forther east, particularly in Austria and Eastern Switzerland. And yes, Föhn does not always reach the valley floor, certainly not east-west ones. But above it can be vicious. Crossing the alps or even going near the ridges in Föhn is often very dangerous or even suicidal, even with much bigger planes.
Transition altitude has NO relevance whatsoever to terrain avoidance. None. TA in the Zurich area is 7000 ft, obviously south of us there is stuff up to 17000 ft. All the TA sais is at what altitude you change your altimeter to FL in that airspace. Printing it on a VFR map has no relevance and, as we can see, is potentially distracting.
Mooney_Driver wrote:
Printing it on a VFR map has no relevance and, as we can see, is potentially distracting.
Why? VFR pilots regularly fly on flight levels too!
Peter wrote:
A transition altitude is just a figure where you change from a flight level to QNH, and is irrelevant to flying OCAS. I don’t know anybody who uses the TA value autonomously.
In Spain you do this (or at least used to do this). In the south there are two (or three) different TAs and you set altimeter accordingly, no ATC involved.
Mooney_Driver wrote:
Printing it on a VFR map has no relevance and, as we can see, is potentially distracting.
Disagree, see above.
dublinpilot wrote:
Why? VFR pilots regularly fly on flight levels too!
Exactly. In Germany, where the accident pilot came from, you are supposed to set your altimerter to 1013 when flying above transition altitude (usually 5000ft here) so this would have been “normal procedure” for him.
Looking again at the SIA chart, it seems to drop out spot elevations fairly randomly… whenever there is some CAS etc to depict they just leave off spot elevations.
It is a really dangerous chart, notwithstanding the position that VFR pilots should never fly in IMC. The problem however is that the chart is also virtually useless for VMC on top emergencies under VFR…
In Germany, where the accident pilot came from, you are supposed to set your altimerter to 1013 when flying above transition altitude (usually 5000ft here) so this would have been “normal procedure” for him.
And FR24 shows him at 6500ft but actually since FR24 doesn’t know the QNH that “altitude” is actually a flight level, for all FR24 traffic.
That suggests too he was using the SIA chart and set 1013.
While everyone here is speculating about the cause of the tragic accident, I noticed something else. Until now I thought at the image of the gendarmerie which I published in post #30 a part of the fuselage is to see. Certainly, others thought this too. Now I studied the high-resolution picture again. It is not the fuselage, but the left wing. In Germany airplanes must have the call-sign also below the left wing. The flaps are to be seen at the bottom and the left recognition light (an option which the D-ESPJ had) in the upper right corner. Above, between the wing and the summit lie several colored things. Probably parts of the luggage. So it seems, that the plane has struck the summit, is broken there and dropped down the slope. Only the wing and some of the luggage were stuck on the rock. The rest must be lower.
A few days ago I was flying between Lausanne and Montreux over lake Geneva at 3500 ft. Abeam Lausanne, the water was calm but I could see from 15 NM away how stormy it was abeam Montreux, the white wave crests, the ripples on the water all hinted to 5+ Beaufort.
And you could see the wave pattern which looked like a gigantic delta originating from the Rhone river.
Montreux is directly at the opposite end of the entrance to the Rhone Valley. When the aircraft arrived there, winds aloft were above 30 knots and very turbulent. I had to climb to 7000 ft to somehow evade, but it was still far from calm air. The point I want to make is that local wind phenomena in the Alps can be very extreme AND very local.
I still think that the poor pilot died before even realising what was happening. With his level of experience I find it hard to imagine that he intentionally got himself into a terrain structure he was not 100% sure about in IMC. I think he got smashed down from what he thought was a safe altitude.
In 2015 a twin crashed into a mountain slope in VFR and a Saratoga was lost to a gust while doing a steep turn near terrain.
