Regarding SkyDemon: in my way of using it, the high terrain coloring setting self deactivates quite regularly, maybe even after every flight, didn’t pay much attention… I wonder if this is a bug or there is some kind of rationale behind it.
I wrote this early on in the thread, I think: most likely he was trying to fly low, due to the baby not having oxygen.
The conditions were VMC so all the satnav stuff would not have been applicable. You don’t need SD to tell you where the mountains are.
Yes, but he must have researched „how low“ to fly. Why pick an altitude so low over the pass?
This is why I think he was flying the ref alt of the GAFOR route, thinking this is like a VFR route altitude that is recommended? Then, realizing he is too low for the pass coming up on the right, panic set in and a left turn was initiated into even higher terrain?
The GAFOR altitudes should be changed to ref alt +1000ft, that would be more fail safe.
On the photograph taken in the cockpit you can see that terrain coloring was not active on sky demon.
This one really gives me the chills. Especially thinking of the wife and baby in the backseats :( :( :(
Peter wrote:
I think: most likely he was trying to fly low, due to the baby not having oxygen.
The minimum crossing altitude is 8500 ft. That is in the region of what pressurized airliner cabins get to as well. Noboy gives a damn about taking babies up in airliners.
Looking back at the thread @boscomantico pointed to I think he might have a point:
jgmusic wrote on the 21st of June 2018:
The published ‘reference’ altitude should therefore be generally treated as the minimum altitude for any given route. Makes sense.
The GAFOR reference altitude is 6800 ft. The crash site is at 7400 ft and he was higher before crashing.
This may well have been the fatal misunderstanding. That hight refers to the highest obstacle on the route and is NOT the MSA, by no way.
I think if the SUST had seen this statement it would be in the report.
Yes that’s the statement I meant.
The GAFOR reference altitude is 6800 ft. The crash site is at 7400 ft and he was higher before crashing.
You mean lower during the 50 nm leading up to the accident? Or you mean he started a climb very shortly before the crash?
Mooney_Driver wrote:
This may well have been the fatal misunderstanding. That hight refers to the highest obstacle on the route and is NOT the MSA, by no way
This is tricky. There have been several suggestions here that the reference altitude should really be the MSA and not the highest obstacle within a corridor. That makes sense in a way, but on the other hand the cloud bases in the GAFOR are relative to the reference altitude. If the MSA is used instead, if could give the pilot the impression that the cloud base will be higher than it actually is. I don’t see an easy way out of this dilemma. What would probably be best is to keep the reference altitude as it is, point out everywhere that the reference altitude is not an MSA and chart a route MSA.
Airborne_Again wrote:
This is tricky. There have been several suggestions here that the reference altitude should really be the MSA and not the highest obstacle within a corridor.
The important bit is that they are DIFFERENT and made for different purposes.
The MSA defined on the maps is intended for a safe passage of a pass or route. If I reckon right it is 1500 ft above the highest obstacle on that route segment.
The reference altitude in the GAFOR is intended to calculate a CEILING over ground, in this case over the highest obstacle rounded up to the next 100 ft.
So the reference altitude for route 44 is 6800 ft which is slightly above the pass which is 6578. This means, with Marginal you have a ceiling of at least 1500 ft on top of 6800 ft. That is 8300 ft, which in turn is the MSA indicated on the chart.
In practice this means that if the GAFOR gives X or M, you will be below MSA. D and O means ceilings above MSA.
Marginal conditions should only be used for pilots who are intimately familiar with the terrain and who have a darn good reason to fly there: Practically that means SAR pilots. Not many others will try to negotiate a pass in M conditions.
Snoopy wrote:
You mean lower during the 50 nm leading up to the accident? Or you mean he started a climb very shortly before the crash?
He started a climb when going into the valley. The crash site is located at 7400 ft. He did not fly into that crash site horizontally, but was above that altitude when he stalled and crashed into the terrain. So he must have been at least at 7500 ft or so when the stall occurred.
the pass itself is at 6600 ft, there are some obstacles hence reference altitude of the GAFOR is at 6800 ft. So he was at least at 600 ft above that when he stalled. Had he flown in the center of the valley, he would have been still below the MSA but he would not have been in the terrain he ended up at. Also if he had flown on the right hand side of the valley, he would have had a much better visual environment to fly in. Where he flew, he probably not even saw the lower area of the pass, which he could have crossed clear of terrain with 600 or 700 ft above it. Instead he flew towards a much higher mountain.
Looking back at that thread I fear that he misunderstood the meaning of the reference altitude and thought he could actually cross the pass at it. On the other hand, he did cross the Simplon once before and should have known better. At the same time, there is no reason to fly that low anyway. The height of the terrain is clearly visible on all the maps and it is also clear that you need to fly at least 1500 ft above the pass. And that is 8300 ft.
Whatever the lessons learnt are, flying that low over a pass (even at MSA) is something I definitly try to avoid unless forced by weather, which would usually mean I won’t fly at all. Weather was no issue here, so flying higher would have been possible and the best way of doing it. 9500 ft or so would have made this flight a non event.
I don’t think this accident has anything to do with the ability to read chart, select altitude or reading gafor? the pilot flew that pass previously and had a very capable aircraft…
I know Jonathan very well, I flew that Arrow few times while renting from North Weald, we also met his wife once when we both flew to LeTouquet in club fly-out, the only reason I can think of why he was flying low was mentioned above: he was flying with his baby
If you are limited to 7kft you will have to fly to Venise via Corsica and add 300nm of fuel & time to the trip
I fly with babies, if you go near terrain it’s easy to get into similar altitude optimisations: max 7kft-8kft cruise and +/-500fpm profile, from there all it takes one single moment of inattention
Ibra wrote:
If you are limited to 7kft you will have to fly to Venise via Corsica and add 300nm of fuel & time to the trip
Or via the Brenner pass in Austria.
Ibra wrote:
the only reason I can think of why he was flying low was mentioned above: he was flying with his baby
It’s the first time I hear this. Babies fly on airliners all the time and while it’s a pressurized cabin, they also reach 7-8 k ft regularly. The actual pressure and O2 level is not a problem normally, what has to be done carefully is change in altitude. We had my daughter in an airliner 1 month after her birth and she coped just fine. She was given the bottle during descent which did the job.
Jonathan had all the time to climb to 8300 ft and stay there and then descend slowly back to whatever he felt safe. If you are limited to altitudes below that, it is no go.
Does anyone know that the first time Jonathan crossed the Alps whether he had the baby along as well? Because at that time, he overflew the pass without any problem.
I think it would be difficult to plan this “mountain flying” route for altitude, and be certain to keep it below say 8000ft. There isn’t good or easy to use data out there. You would need a 3D profile, fly it with a suitable clearance, and note how high you had to go.
SD is mostly not well understood; it has tons of features and most pilots use it only in a basic way.
It could have been done more easily on a flight sim. You can get a great terrain database on those.
