Mooney_Driver wrote:
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.
Precisely what I assume as well.
Ibra wrote:
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
What is your assumption what happened?
I am not making assumptions more sharing my experience, my partner did put 8kft ceiling on “baby flying”: very cold, less oxygen…while ago, she got her solo Diamond gliding badge on cannula and we did plenty of gliding in Alps, that was long time ago it’s “the family model” now and things have changed slightly
Same I don’t do “long water crossing” to UK at FL120 with the babies, I cross via Dover
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.
We are talking piston GA here? did you fly with 1 month baby daughter in M20C as well? yes B737 like cabin is at 8kft in pressure with decent spO2 (I gather convincing family to cross Alps at FL100 in piston with young baby is very different matter, no need to convince other pilots)
Just my vague guess why that flight portion was done at 7kft rather than safely climb and cruise at FL120, especially, given aircraft & weather but it could be other reasons (e.g. ipad glitch, reference vs safe altitudes…)
Peter wrote:
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.
Why would that be? All you need are three things:
- aviation chart
- topo map (optional, but very helpful in this case)
- pencil
That route can be planned in about 10 minutes, no fancy stuff like SD or FF required.
The charts show only spot elevations, generally.
Almost nobody flight plans with (or flies with) a topo map.
Jonathan was fairly new to this game.
Working out safe altitudes for passes is not that easy. Look at this thread. It goes a bit all over the place but you get the idea. @antonio ’s posts there are great; he did it the right way. You would need to fly it with FSX or whatever the current product is – something with the hi res terrain data. The risk scenario in that thread is very similar to the accident flight.
Of course I would fly straight over the top, even VFR, but that definitely needs oxygen, and in some places (e.g. Zurich CAS) you cannot go above FL129 (Class C, some private ATC policy) so you are quite close to the terrain, so you need a cloud-free day. And I wasn’t the pilot here so this is irrelevant.
@ibra so you’re saying he selected a “random” low altitude due to the baby? He must have gotten that altitude number from somewhere? My bet is, that somewhere is SkyDemons GAFOR route depiction, showing a reference altitude that was misinterpreted as a “safe” altitude. He even posted this on here.
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.
Surely, he must have checked to be above any terrain enroute However, for some reason, he came to the pass at its elevation, and not above. It looks very much like he was convinced the GAFOR ref provides a safe altitude, and maybe the fact that a lower altitude was preferred due to the baby helped create this misunderstanding. We see what we want to see.
Peter wrote:
Working out safe altitudes for passes is not that easy.
Is it really? It just took me less than 30 seconds via Googling “mountain flying” and “safe altitude for crossing ridges/passes” to find this:
Ridge and Pass Crossing
On most mountain flights, you will need to cross at least one ridge
or pass. Experienced pilots recommend crossing a ridge or pass at
the ridge elevation plus at least 1,000 feet. If the winds at moun- tain top level are above 20 knots, increase that to 2,000 feet. Plan to be at that altitude at least three miles before reaching the ridge and stay at that altitude until at least three miles past it. This clearance zone will give you a reasonable safety zone to avoid the most severe turbulence and down drafts in windy conditions
It took me another 30 seconds to google “Simplon Pass Elevation” to come up with 6581ft. I’d not be comfortable there below 8500ft.
Why do you plan to fly at “safe altitude”? you can cross Alps at FL120 in that Arrow
Ibra wrote:
Why do you plan to fly at “safe altitude”? you can cross Alps at FL120 in that Arrow
The general fear of ATC/airspaces keeps VFR only pilots lower. And in this case, a baby… no way to go FL120.
As far as is known they had no oxygen.
And oxygen is extra tricky with children; it can be done but they need close supervision.
I have never flown with my family after my child was born, partly as I have not had the time to stay proficient. Altitude would never have been a concern however.
I have to admit that Jonathan’s accident put a massive damper on my ambition to go back to flying. Reading the report however has aliviated that largely.
Ibra wrote:
yes B737 like cabin is at 8kft in pressure with decent spO2
I have never actually measured my spO2 in either but I reckon 8000 ft is 8000 ft, whether it is in an unpressurized cabin or a pressurized one
Apart, us mountain folks take their kids up high regularly on terra firma. I definitly crossed alpine passes with my daughter when she still was a baby in my car. Some were well over 7500 ft (Flüela 7800, Albula 7600, Julier 7450) . Some of the roads are quite steep and you can feel your ears pop as well. Never had a problem. Certainly not oxygen wise at that altitude. Tons of kids go up with cable cars to heights well beyond 10’000 ft and nobody thinks anything. For me, going up the Titlis in a cable car was noticable at 11000 ft AMSL and higher DA but I’ve never experienced a similar sensation in an airplane, even well beyond 10’000 ft for short times.
Frankly I think this is an irrational fear by people for whom mountains are something exotic. Clearly, with a baby you’d try to descend shallow. I’ve encountered many airliners though where pressurisation is quite unstable and descent rates are way beyond anything I’ve ever experienced going down in my own airplane.
