Maoraigh wrote:
Could a katabatic wind occur there?
Nope. We have Föhn (high pressure south of the alps with rain and clear but turbulent conditions north of the the alps ) and Bise with a NE blowing wind which obscures the mountains north of the alps. At this time when G-BVFH was en route none of those conditions applied.
Maoraigh wrote:
Question for locals: Could a katabatic wind occur there? Pics show snowcapped peaks. Cold air directed down a side valley.
In my opinion the wind was almost nil.
No wind at Sion and QNH equal between Geneva – Lugano and Zurich (a QNH different from + 4hPa between these points will create wind, Bise or foehn)
can be 7-10kts at the pass of the Croix de Coeur, which is slightly higher
Antonio wrote:
Fly close to one side, and as far as possible, on the right side
This is the most important thing in mountain flying as to 1.) flying in the right part of the valley which hopefully prevents opposite traffic which hopefully flies close to the opposite ridge and 2.) due to the turning technique explained by Antonio in his post to get a safe distance to do a 180° turn. And 3.) and maybe most importantly stay in contact with FIS all the time.
And obey the way of overflying a pass at a 45° angle to be able to turn around with the least amount of turning radius.
Which side of a canyon to fly down (a valley is wide enough for light GA to make this less critical), has more factors to consider than just traffic.
On the assumption you are not flying in a high wind with mountain rotors situation which will swat down even a PC-6, flying on the shady side counterintuitively may be more logical.
There is better visibility outside the glare and if you need to turn around you are turning towards rising air on the sunny side, which is safer. Turning from sunny side to shade means you are potentially turning towards downsrafts, and in the glare of the sunny side you may not be seeing what you are turning towards.
I believe the AIPM in Italy briefs this aspect quite thoroughly and also this is what would be practiced in North America.
As for the turn no semi aerobatic wingover etc is correct. A 30 to 40 degree bank turn at a reasonable slow speed with a good margin over Vs (a 40 degree level turn is increasing Vs by around 20%), is sensible. The radius of the turn is a function of bank and speed, limited by ensuring a safe margin over the stall speed. If turning towards lower terrain-which you would be-allows lower G in the turn so the bank could be steeper if the escape turn allows descent.
Not sure this post is good form (especially as a newbie here) but one thing I’ve always disliked about ‘pilot folk’ is the way they pick apart the pilot in accidents such as this.
We’ll probably never know exactly what happened, and I’m sure the authorities involved will do their best to find out what can be understood. But a pilot and family were killed in an aircraft, of similar type lots of us have probably been in. Does it really require making online assumptions about his skills/judgement etc?
I guess for understanding and future safety it’s a useful process, but just seems so harsh. After all even looking at another fatal crash, it seems the internet assumptions (or even official ones) were probably wrong. A lot of it just comes across as ‘I’m a much better pilot’.
I often contemplate taking my young son up, and this story makes me think much harder about it. In fact, flying at all!
(Not aimed at anyone in particular btw just a feeling about these discussions that happen on all forums)
I would agree and perhaps the mods can move part of the thread to discussing VFR in mountainous terrain.
My posts were purely in the interests of promoting safe technique-I have no view on what in fact may have happened.
The Italians, French and Swiss mountain pilot community all have an excellent body of knowledge and training in mountain flying is recommended.
the way they pick apart the pilot
Is there a particular post where this has happened?
the authorities involved will do their best to find out what can be understood.
In some countries in Europe (not all, unfortunately) they do that, but usually it takes a year or two for the report to come out, by which time the learning value is minimal. This is partly because almost nobody reads accident reports; basically almost nobody reads PDFs. If there is a thread which is read by 100 people, and someone posts a PDF, maybe a few of them will even click on the PDF. That is generally the case on the internet. Whereas here you get a “live” discussion which is a lot easier to take in. Another factor is that accident reports tend to avoid discussing factors inherent in the investigating country’s airspace or mapping organisation…
I am sure many here wish they had the opportunity to draw the pilot’s attention to some things discussed here, before his flight.
I tend to move off topic posts to a new thread if they have specific value and don’t contain significant material relevant to the original thread, and if there is a number of them, OR the individual post raises a really valuable point.
VFR-UK wrote:
Not sure this post is good form (especially as a newbie here) but one thing I’ve always disliked about ‘pilot folk’ is the way they pick apart the pilot in accidents such as this.
This site in my view is actually pretty fair and intelligent about the way posters behave in relation to pilot blame. Other forums are far less forgiving. Look, if we take the facts known, plane crashed, appeared to be level at 6k, when the MSA should have been around 8300. People lost their lives.
Not known, was there an aeroplane issue that prevented further climb? Was there an internal issue with the people on board that possibly distracted pilot? Was it a simple error that then gave rise to a greater issue for the pilot A myriad of issues (swiss cheese) that caused the incident, some of which can be discussed openly, some of which will require a report by AAIB which even then may not tell us what actually happened?
In the interim be safe in the knowledge that the Mods understand and are alert when posts go off beam…my experience.
Apart the fact that they could have been poisoned by CO, the PA set to their course, but as stated by previous folks, unlikely to happen because this is very unpractical to do with Garmin 430.
BeechBaby wrote:
Not known, was there an aeroplane issue that prevented further climb?
The wreckage is located in or close to a dry gully lying along the gradient of steepest ascent and orientated in the direction of approach. By comparing site photographs (link) with a model based on the Swiss digital terrain model swissAlti3D the position can be estimated to within about an arc-second as N461434 E0080229 (see comparison at link) whose elevation is 2 247 m (7 373 ft). See position on national Swiss map (link).
The altitude at the last logged FR24 position, 6.6 km away, was 6 500 ft based on the known facts. See my post # 350. The slope between these known positions is 2.3 degrees. The handbook best rate figure is 460 ft/min at MCTOM equivalent to a 2.6 degree slope in still air with ISA +9 K.
Edit: s/per cent/degree
