Single engine public transport forbidden? Canada was built on the back of single engine public transport. To this day, if you are going anywhere on the west coast it is going to be in a single engine Beaver or Otter. A single engine aircraft probably arrives in or leaves Vancouver harbour every couple minutes. 60,000 to 70,000 movements per year. Some of those will be twin otter, but you get the idea
I think it is only the UK that forbids this….
Eurocontrol is ready for FL600 
I am googling on how Concorde ever got certified. Yes the pilot has to wear a mask, but that’s the easy bit. If pressurisation fails, a descent is obviously the immediate action – to FL160 I think (@antonio and @snoopy will know) and ETOPS limits take into account the much shorter range which you then have. But you will have time – depending on how bad the leak is, versus how much the pressurisation system can replenish it. If a door or a window blows out then you have a problem, but for FL600 the pilots need sealed masks because even 100% O2 is not enough to achieve the required O2 partial pressure in the lungs (say 2psi; 3psi is MSL) at FL600.
Some history on SE public transport ops in Europe is here. I believe there have been some recent changes because the PC12 AOC ops were limited to glide range of land.
A jet engine is not “turbocharged”; it is normally aspirated.
Why not? The turbine itself is more or less a large turbocharger. Only you have a combustion chamber in between the compressor and the turbine instead of a piston engine. But that’s probably not what you meant: You can of course turbo charge a turbine engine by adding more compressor stages but then it’s a totally different engine. Might this in the end be the real reason for the engine choice? There are almost no planes flying at that altitude especially no turboprop planes and hence no engine working at that altitude or at least not certified for that altitude. A piston engine however can be cheaply adapted to that altitude by duct taping a bunch of hairdryers to the air intake like they did on that already mentioned Grob plane. Or to make that short: High altitude means big turbine means €€€.
Clipperstorch wrote:
You can of course turbo charge a turbine engine by adding more compressor stages but then it’s a totally different engine.
I don’t think that would work or is actually required, the turbine is sized appropriately to meet the power needs of the compressor and to propel the aircraft (if the turbine also drives a fan or propeller). If you increase the power needs of the compressor you will have to increase the power output of the turbine, which you can do with fuel until you are temperature limited because the turbine is similarly effected by the reduced density. Which is what often happens with many turboprops at altitude.
So in fact I think the solution is simply a bigger engine
Peter wrote:
If pressurisation fails, a descent is obviously the immediate action – to FL160 I think
It depends on the route and the O2 you are carrying. In the EU for CAT, CAT.IDE.235 refers to O2 supply and this and terrain dictates your descent profile. Basically from the pilot’s perspective you are OK as long as you a have reliable O2 supply, but you need to be at FL100 or below by the time you have 110 mins of pilots O2 remaining. From the pax perspective you need to descend to FL150 or below by the time you ran out of O2 for some pax, and FL100 by the time you cannot supply O2 to at least 10% of pax. The time required for that descent depends on your O2 supply and the type of aircraft, but in all cases demands that you plan to be at FL100 down from the certified ceiling within 10 mins, unless you can supply O2 as above.
Actual procedure depends on the type, the O2 being carried for pax and crew, the route (MSA) and the airline.
In practice, for most routes, you will immediately descend to FL150 and, once MSA allows, on to FL100.
There is more than just oxygen at FL600? what about body pressure, I think past FL500 pressure altitude blood boils at 37C deg with or without oxygen? the pax & crew are not planning on wearing Virgin Galactic suits?
Also, if you’re breathing pure oxygen at 50k ft, as you descend you will become delirious breathing pure oxygen, so there would need to be an altitude dependent mixing system to prevent that
I think past FL500 pressure altitude blood boils at 37C deg with or without oxygen
There is a lot of stuff on google about this. It doesn’t boil. A human can exist in vacuum (the skin contains the pressure), though obviously not for long
in all cases demands that you plan to be at FL100 down from the certified ceiling within 10 mins, unless you can supply O2 as above.
Presumably airliners address this with the automatic drop-down oxygen generators? But they won’t be any good (continuously, without descent) at FL300+, due to insufficient partial pressure achieved. So there must be a tradeoff, involving the timing of the descent.
From FL600, unless you provide every passenger with a pressure mask, you have to get down really fast. On an explosive decompression they will be unconscious within some 10 seconds and brain damage takes just a few mins. But this must have been addressed already with high-end bizjets which have ceilings of FL550. How was it done?
It would be fascinating how Concorde addressed this (certified ceiling FL600 and often flew at FL600).
I can’t help but think this discussion is even more ridiculous than the aircraft looks ;-)
The FL600 comes from a patent application ages ago, looking at the website they seem to be planning a more conventional FL300 (probably FL290 in practice).
The engine is currently certified to FL 250 only (see TCDS although there may be a newer one)
A good deal of marketing hype, but at least the thing flies, which is more than can be said for the ‘Raptor’ project.
Peter wrote:
There is a lot of stuff on google about this. It doesn’t boil. A human can exist in vacuum (the skin contains the pressure), though obviously not for long
Ah not talking about Sci-Fi movies where heads blow up in vacuum: ISS when someone forgot to latch the Soyuz doors
Just why AF pilots need to wear a pressurised suits even with their masks, but the limit is FL600 not FL500
https://en.wikipedia.org/wiki/Armstrong_limit
On a side note with those impressive numbers, I would say “I have seen the future of aviation innovation, and it is butt ugly”
