high altitude single engine

[glexdriver]

Hi all,
me and my wife are thinking to buy a single engine airplane. We are looking to the SR-22 or the cessna 400. I was looking at their websites and both claim altitudes well above 10.000 ft. I would like to know? Are these airplane presurized in some way? or they really just on oxygen bottles? I will ask this question to them but I would like to hear from you the real story.

[vanHorck]

to my knowledge neither are pressurised.

Up to 18000 ft you can use canulla's for oxygen, a good system being Mountain High O2 which feeds oxygen ondemand (pulse). It is a fully automatic setting which requires only a small bottle. The downsize is it runs on 2 AA batteries, so you must make sure you alwys have spare ones.
Above 18.000 you ll formally need oxygen masks which are less comfortable.

Many unpressurised planes fly in the 12.000 to 25.000 band, because the air is generally more smooth, it is more fuel efficient, faster and generally above the weather.

To practically fly there however, life is a lot easier with an IR rating

[S-Works]

I fly my Cessna well above 10,000ft frequently. Book ceiling is 18,000 but it will go to FL200 on a good day.

I just use a MH Oxygen kit and canulla.

There is a gain to be had by increase in TAS and lower fuel consumption as well as getting clear of weather that would normally deny a non de-iced single from flight.

However for a non turbo engine the loss of ambient pressure means a lower performance even allowing for the increase in air density and the lowering of back pressure on the exhaust so you need to find the perfect cruise level for each type. My Cessna the perfect balance of altitude and performance is FL120. Getting into the Turbo types like the 400 or SR22 that level moves higher. I am not sure what the full throttle height for them is but would imagine it is around FL120-140.

[SNS3Guppy]

Above 10,000 isn't exactly high altitude.

I spent much of my 1,000 hours in 172's above 10,000...and that's not really what you'd call a high altitude airplane. When flying from fields with density altitudes that were often close to 10,000' in the summer, and actual elevations starting at 5,000 on up. A light airplane, even a normally aspirated airplane, shouldn't have any problem flying above 10,000'.

Are you looking for altitude or speed as your primary concern? Ten grand won't get you over much weather, and certainly not convective weather...it will generally get you closer to icing conditions and put you in weather. TAS increase isn't that significant above ten to make it much of a big increase.

The SR22 choice would have to be more one of comfort or speed, than choosing for it's altitude capability. Just about anything can go above ten thousand. I've taken a little Cessna 150 to nearly 18,000 before...so certainly you can expect ten grand all day long in a Colombia or Cirrus. The real question then is what are your goals once you get there?

[scooter boy]

IMHO for high altitude performance in a single there is only one manufacturer that is worth considering and that is Mooney.

The factory installed TKS deicing system is FIKI certified (unlike any other single) and is extremely effective. This is a single engined piston aircraft that you can cross frontal systems with.

In the Ovation 2 (non-turbocharged) you can make FL200 at MTOW.
This will get you over most of the weather except the really convective stuff.

The Acclaim will give you FL250 which will get you over slightly more weather but with a far higher fuel burn.

These airframes are not only sleek and very aerodynamically evolved but also very rugged, time proven and superbly efficient, more so than anything else out there.

I've had a TKS equiped ovation 2 for almost 5 years and have no regrets.

The only thing I wish for is weather radar, IMHO the stormscope on its own is inadequate for flying through lumpy bumpy weather with.

I have no financial interest in the Mooney Airplane Company and this is based on my opinions of having flown (been flown in and trained in) lots of other stuff over the previous 10 years.

SB

[IO540]

Of course there is also the TB20 or the turbocharged TB21 :)

Not made anymore but there are a number of potentially very fine 2002 specimens on the market, and Socata remains very much in business making the TBM850.

The TB2x, with full TKS, is certified for flight into icing, but only on a G-reg, not on an N-reg (because the FAA requires two alternators, etc).

Do bear in mind that full TKS costs about 50-70kg and a turbo costs another ~50kg. While the basic TB20 (20k ceiling) has a 500kg payload, the TB21 with full TKS is really only a 2-seater albeit a highly capable one. These payload tradeoffs will apply to every other type, too, so one needs to define one's mission profile carefully. For a start, most of this mission capability is not usable without the full IR unless one just wants to takeoff from Norwich and zoom up in circles over Anglia :)

glexdriver - check your PMs.

[Cobalt]

Back to the original question - Colucessna 400, SR22 Turbo and Turbo-Mooneys all come with built-in oxygen systems as standard equipment.

If you have the sort of money to buy a $600k+ aircraft new and want to fly long legs with more than one passenger I recommend you also look at six-seaters (Saratoga, Bonanza) as they will actually give you decent range with four people on board.

Any aircraft that can take full fuel and fill all seats has tanks that are too small :).

In Europe I agree with IO540 that having a Turbo is only worth the expense and the payload penalty if you are a regular high-above-the-weather flyer, which in practice means instrument rated.

[Cobalt]

and zoom up in circles over Anglia

No idea why anyone would do THAT ;)

C.

[B2N2]

Wasn't on your list but the DA-50 will be pressurized:
Diamond Aircraft (http://www.diamondaircraft.com/aircraft/da50/specs.php)

[IO540]

Indeed, but the DA-50 is what in the software business is called "vapourware", and currently anything from Diamond, including their current products, is in more or less that category because it is pretty obvious that the future of the company itself is not exactly assured.

Just seen yet another DA40 taxi in, followed closely by a couple of fire engines. Very sad for the businesses, and the private owners, who trusted this bunch of double glazing salesmen.

Diamond knew exactly what they were doing when they sold the DA40-180 avgas version only in the USA.

To paraphrase Clint Eastwood, do you feel lucky enough to be a beta tester for yet another product, especially one coming out of a company whose cash flow must by now be clutching at every straw they can find.

[glexdriver]

thanks for all the replays.
What we are looking for is an airplane with good altitude capacity (up to 180) able to fly in icing condition, and IFR rated.
Up to now the SR22 meet all these need. About the cessna 400 is not clear if the oxygen is built in like on the SR22, and if it has some sort of anti-icing.

[englishal]

Is the SR22 cleared for known icing? - I didn't know that.

Diamond knew exactly what they were doing when they sold the DA40-180 avgas version only in the USA.
And this is a fine aeroplane...flies very well and the XL version cruises at 150 kts at 9 USG per hour. Coupled with WAAS enabled synthetic vision and you have a really great IFR machine.

Maybe it is a EU/US thing bit all the Diamonds I have flown in the USA are amazing pieces of kit, extremely well made and people are still buying them.

[172driver]

The Cessna 400 was until recently the Comumbia 400 and I think you'll probably get more info about this bird on the US part of Pprune or on any US GA forum (Avweb, etc). I don't think there are loads of them around Europe.

If pressurization is something you'd like to have, then you could also be looking at a C210P. While nowhere near as fast as a Mooney or Cessna 400 (and of course second hand) these are very capable machines.

[FullyFlapped]

thanks for all the replays.
What we are looking for is an airplane with good altitude capacity (up to 180) able to fly in icing condition, and IFR rated.
Up to now the SR22 meet all these need. About the cessna 400 is not clear if the oxygen is built in like on the SR22, and if it has some sort of anti-icing.
5th November 2008 15:53

Hmmm .. tricky one : single engine, turbo-charged for high ceiling, fully de-iced, fast, carries huge load (6 seats) - where are you going to find one of those ?

Pssst - wanna buy my 210 ? ;)

[glexdriver]

actually I never told that I need 6 seats. Most of the flights will be 2 person and a bag each.

[PlasticPilot]

The remarks about FIKI certification makes me feel the need to ask if it's sensible to fly in any icing with a single engine, given their performance...

IMHO, FIKI and piston does not go well together.

[Thud105]

I flew a Columbia 400 in 2005. If you do buy one may sure it has the (optional) speed brakes.

[n5296s]

the DA-50 is what in the software business is called "vapourware",
The prototype looked pretty solid at San Jose today. It's a gorgeous aircraft, the rightful successor to the TR182 and the 210 (and the P210, given that it will now apparently be pressurised). But it's also true that you can't have one yet - the salesman was talking about 2010.

As for the stability of Diamond... have you seen what's going on with Mooney? Sadly, the only companies you can count on right now are Cessna and Cirrus. Everything else is a gamble - it even looks as though Eclipse will go under.

Also at San Jose was the DA42-L360, with two IO360s. I didn't get a chance to sit in it but I guess they must have made the console a bit wider to accomodate six levrs instead of two. They were saying it will ship in Q1/09, with the DA42-NG (with the Austro engine) later in the year. That would be the plane I would buy if I was in the market for one (which unfortunately isn't very likely at the moment, although my TR182 is more than fine for anything I plan to do anyway).

You really can't blame Diamond for the problems at Thielert. Curiously, there was also a stand at the Expo showing the Thielert engines, under another name (I forget what) with "manufactured by Thielert" underneath.

n5296s (or maybe oe-v50)

[IO540]

As for the stability of Diamond... have you seen what's going on with Mooney? Sadly, the only companies you can count on right now are Cessna and Cirrus. Everything else is a gamble - it even looks as though Eclipse will go under.

Indeed but there is a difference between buying a new design plane and buying an older / established one.

The former would be a major problem if the manufacturer goes bust - lack of warranties for a start, and if it is a slightly unusual type with unusual parts (like Thielert engines) then the plane might actually have to be scrapped.

The latter is a lot less bad because what matters then is whether the spares operation has value as a business, and most spares operations have such a huge value that their future is assured.

I fly a 2002 TB20 which has been dead since 2002, but the spares operation will always go on, and the whole plane is easy to work on, and all the bits of relevance (engine and accessories, avionics, electrics) are standard American parts anyway. Importantly, there is a large base (c.2000) going back to 1979 so there is a sufficient demand for airframe parts (which aluminium planes past c. 15yrs start to need) and this keeps the spares operation in money. Nobody buys Lyco engine parts from Socata!

I guess Mooney would be in the same category - a huge and well aged base generating a constant demand for parts. And it is a bog standard piece of aluminium with American avionics and an American engine; all off the shelf items.

But if Thielert goes bust (very likely) and if Diamond were to also hit the rocks, the existing diesel fleet would be doomed because it is not likely that the TC owner would get a new engine certified. But obviously it does depend on when (if) anything happens. Diamond must be getting close to having the new engine sorted, certification wise if not field tested....

You really can't blame Diamond for the problems at Thielert. Curiously, there was also a stand at the Expo showing the Thielert engines, under another name (I forget what) with "manufactured by Thielert" underneath.

The interesting thing, having read some summary of the events at Thielert as reported in the European press, is that the Thielert issues (the fraud, etc) were well publicised in Europe years before they appeared in the UK press. Obviously Diamond were aware of them from day 1. But Diamond's business is selling planes! They obviously made an early decision to cover their options and quietly develop another engine ASAP.

[421C]

thanks for all the replays.
What we are looking for is an airplane with good altitude capacity (up to 180) able to fly in icing condition, and IFR rated.
Up to now the SR22 meet all these need. About the cessna 400 is not clear if the oxygen is built in like on the SR22, and if it has some sort of anti-icing.


The Cirrus is available with TKS deicing - but it is not certified for flight in known icing (FIKI).

The distinction is that a non-FIKI aircraft has to exit icing conditions immediately upon encountering them, and should not enter "known" icing conditions. This latter definition is subject to some interpretation - it certainly means conditions where other aircraft have reported icing, and may mean conditions where the forecast has a high degree of likelihood that icing will occur.

My impression is that the lack of FIKI in the Cirrus is not just a technicality. Anecdotally, I believe the Cirrus wing design, whilst very efficient, is particularly poor at handling icing conditions. I am sure the TKS helps overcome this disadvantage, but I have no idea how closely it brings the airplanes capability to true FIKI levels.


The remarks about FIKI certification makes me feel the need to ask if it's sensible to fly in any icing with a single engine, given their performance...

IMHO, FIKI and piston does not go well together.


Icing is not a binary condition of not-present/safe vs present/danger. It is a continuum from the many times you are in visible moisture below 0C with no trace of icing, to severe conditions that must be exited in any aircraft.

A FIKI certified piston aircraft is safe in a wide range of conditions that a non-FIKI certified one isn't. It makes planning easier, actual flight easier and staying legal easier. The cost and complexity of certified deice equipment is not just a cosmetic...it adds a lot to the capabilities of a piston aircraft. Of course, the value of such a capability is very personal and every lack of capability has a "work-around" some pilots will swear by and therefore say the capability is not that important. If you don't mind being uncertain about a winter trip outcome in advance, planning all sorts of contingencies and becoming an amateur meteorologist wrt cloud tops, perhaps pushing the legal boundary a bit in flight, and being prepared for the (albeit remote) chance of requiring an ATC deviation that needs some explaining afterwards then you don't need FIKI certification in a single.

But it is a myth that "icing and piston aircraft don't go together". In practice, there are a lot of prolonged icing conditions that a FIKI aircraft will handle perfectly safely, and relatively few it can't - most often convective weather you would need to avoid icing or no icing.

Glexdriver, it sounds as if you want an aircraft to do longish IFR trips with 2 people and bags. What you will find is that pilots use everything from a 172 to a Citation to do such trips, and often people swear that their plane is the ideal solution.

I think the Cirrus and Cessna 400 are brilliant modern designs, and the development that goes into these aircraft is fantastic - the Cirrus Perspective is just fab. They are rightly best sellers because the price point and "new" aircraft status attracts a lot of buyers. They are not all weather transport aircraft, but great for leisure trips. To give you an example - if you had a holiday home in southern Europe and wanted to commute to it from northern Europe, a Cirrus is fine if the certainty of getting there is not critical, because in practice you will get there almost all of the time. However, if you wanted to use it for business travel in the winter, or to get to a ski resort at weekends, it won't do.

The other factor is cabin comfort. For regular long trips, the noise/vibration and oxygen requirement is not ideal in a typical single. A cabin-class, pressurised aircraft like the Piper Malibu is a very big improvement in this respect. In comparison, the Cessna P210 is a bit cramped and dated.

With a $500k budget, if my main requirement was fun/leisure with occasisonal touring, I think a Cirrus or C400 would be great. The more I needed long range trips, the more compelling a used Malibu would be.

brgds
421C

[IO540]

I don't fly a de-iced plane but I don't think there is a connection between single-engine and icing conditions capability. A SE can be just as capable as a ME.

The difference is in systems redundancy, but even there the situation is clouded. For example a G-reg TB20 with full TKS is OK for icing but an N-reg TB20 with full TKS isn't, largely because the FAA require two alternators. But the backup alternator is nothing to do with icing capability. I am reliably advised that a TB20 with full TKS is exceedingly capable in icing conditions.

But nobody wants to spend a 4hr enroute sector in IMC collecting ice, which is where an additional operating ceiling comes in, and a turbocharged plane with a 25k ceiling will have a greater mission capability against icing conditions than a non-turbo one with say a 18k-20k ceiling. This is because typical stratus cloud tops are rarely above 16k so one needs to climb above it and then you (usually) have sunshine. If the tops are a lot higher than this, it is due to foul weather (e.g. frontal stuff) or lift up a mountain, and a decisively higher ceiling is required.

With a 20k ceiling, I estimate a 75% random-date despatch rate if not de-iced, and perhaps a 95% despatch rate if de-iced. To get beyond that, you need the capability to handle frontal weather not just enroute but also in the end bits, which needs more kit: radar and a higher ceiling, or (for the brave) just radar :) And the cost starts to rocket up.

Personally I am happy with my 75% rate, achieved with a TB20 with a TKS prop. If I wanted a decisive increment it would have to be a Jetprop - a Malibu Mirage with a proper motor up front. The piston Mirage has had (according to one report I've come across) a 10% in-flight engine failure rate which is a complete joke.

[scooter boy]

I am reliably informed that the inability for FIKI certification of the Columbia and Cirrus rests with their (ugly) fixed gear.
It accumulates ice fast and gets heavy and draggy.
You often hear of pilots describing loss of antennae and aerials after an icing encounter. Any protruberances freeze up fast.

For what it's worth, I would take a Mooney with TKS (same system as in the Hawker jet) over anything else out there. It wins in terms of systems redundancy, speed, (massively in terms of) efficiency, range and general ruggedness. Radar would be nice in addition to a stormscope for crossing fronts, but even my non-turbocharged Ovation 2 can get up to FL200 at max gross without too many problems. On one occasion in the last 12 months having a ceiling of FL250 (turbonormalised Acclaim) would have allowed me to slide over the top of a nasty front (dodging around the CBs
that were going up much higher) but only one occasion. I landed and spent the night in a hotel completing the journey the next morning.

Mooney have slowed production as have most other manufacturers, in anticipation of a tough year or two.
Unlike Cirrus and Diamond, Mooney have been through tough times before and survived - they will no doubt do the same again. The workforce will go back to their homes in Kerville and wait for things to get better. It has happen many times in the past.

Cirrus have massive advertising and marketing investments which they need to rationalise fast, I am certain that capacity will reduce to match market demand. As there will always be people out there who want a plastic parachute equiped car for the sky rather than a plane they will no doubt be fine.

Not sure about Diamond though - their problems are far more fundamental with the powerplant as well as the downturn. I hope they make it.

Eclipse is such a breakthrough product that someone will buy it and take it on even if is fails under the current ownership - it will not go away - the technology is just too good.

SB

[Cobalt]

I am reliably informed that the inability for FIKI certification of the Columbia and Cirrus rests with their (ugly) fixed gear.

If that is the case, why not just de-ice the struts and spats? Can't be too hard to put some TKS fluid there if that is the issue... or fit some fancy thermal-electric tape if that is your preference. Also, unlike antennae, the main gear struts are designed to take the forces of the entire airplane being slowed down by the wheel brakes.

Also can't see why, say, two metres of strut and 50-100 square inches of non-deiced front cross-section for the spats and wheels should be so much worse than the several metres of wing / fin leading edges and square METRES of fuselages, nacelles etc. that are not de-iced even on de-iced twins.

Look at a Seneca, for example - only slightly more than half of the fin leading edge has a boot, the wing inboard from the engine nacelles is not de-iced either, nor are the engine nacelles who have a cross section much larger than any fixed gear...

The primary reason Icing increases drag is not that the Ice is hugely draggy - yes it is, but it also ruins the L/D coefficient of these carefully designed wings, so you have to increase the AOA to maintain sufficient lift. In other words, drag increases, but lift decreases as well and even more so - hence the much higher stall speed of an iced-up wing compared to a clean one.

A good illustration of this is what happens with your tailplane - you will not fall out of the sky because of the drag the ice on it creates, but because you cannot create the aerodynamic forces (=lift) required to control your pitch. The available downforce reduces, while the need for downforce increases because you have to pitch up to maintain the lift of the main wings. This ends with you either running out of elevator authority or the tailplane stalling - both with very dire consequences.

The additional drag is not a major factor, compared to that...

[IO540]

I was advised by a Cessna rep recently that Cessna will not be backing the old Lancair 400 electric de-ice system. They don't think it is proven enough to be associated with the "Cessna" name, and there are anecdotal reports of weird problems with it, melting bits of wings or elevators. The reports are countered by more anecdotal reports of the problems having been caused by dealers mis-wiring the heating elements...

I think a major factor for performance degradation through icing is loss of prop efficiency. I have a TKS de-iced prop which works brilliantly; with some 10mm of rough ice on the wings I lose 5-10kt but the prop is spotless clean.

The prop-only TKS system is quite cheap (1/10 of the full system and hardly any weight penalty) but is not certified for anything whatever, and when the plane was delivered new, the CAA inspector insisted on an INOP sticker being stuck over the ON/OFF switch :ugh: :yuk: . That was after he required EXIT stickers on the doors :) which in turn was after he demanded that the IFR GPS has the IFR features disabled, even though the DGAC type certificate covers BRNAV and the plane was delivered with "approved for enroute IFR" factory stickers :)

But having seen how well is keeps the prop and the front window clean, I think a lot of people blame wings etc for loss of perf when actually they are getting some prop icing which is robbing them of thrust.

[Dimbleby]

Glex, the SR22 is most defenitely NOT certified to fly into icing, as the TKS it possesses is inadvertent icing only. As far as I am aware the Mooney Acclaim or Ovation are the only aircraft (new) with FIKI in this class.

[AC-DC]

Any aircraft that can take full fuel and fill all seats has tanks that are too small .

Not true.
Mine will fly full tanks, 4 av. adults and about 50lbs. in the back and it is only a 4 seater.

[Cobalt]

Should have added a ;)... but this is a half-serious point. What is your endurance and range on full tanks?

Especially IFR with reserves (holding, alternate, final reserve fuel, additional fuel for adverse winds/dodging CBs) you very quickly find your radius quite constrained - even 4 hours endurance can mean an effective 2 hours radius of action at cruise speed - won't get you that far...

However, if your tanks give you, say, 5 endurance / 1000NM + range full up at 200kt (and I mean without exceeting MTOW and/or MLW), please let me know what you fly...

[scooter boy]

But how many journeys are made with all seats full?
I have never had 4 in my aircraft, rarely 3, occasionally 2 but usually 1.

The best option is the Mooney ovation 2 with long range tanks.
I has a greater range than most executive jets and cruises faster than most twins burning far less fuel.

If there are 2 of us then we can top the tanks. If there are 3 than we can fill to three quarters, If there are 4 then I would fill to half tanks.

Half tanks in the Mooney means I have the range of a Cirrus.
SB

[Ovation]

Put the Mooney Ovation at the top of your list if high altitude flight is a priority. Once I took my Ovation to FL200 (22,000 ft density altitude) to get over weather.

Being normally aspirated, it doesn't have the (potential) operational and maintenance issues associated with turbocharged engines.

Try this link to goflying.org to see how high, fast and far you can go.

Track Log | GPS Track Log Viewer | goFLYING (http://www.goflying.org/nav/tracklog/tracklog.htm?trackLogId=1362675720)

[glexdriver]

Hi all,
thanks for alle the infos. Me to I'm considering the mooney, but my wife is still looking at the cessna 400 or the SR22, as these 2 have side stick and she is a scare-bus driver.

[scooter boy]

Ovation,
welcome to the thread,
Great to have somebody else beating the Mooney drum.
That is quite a journey that you linked to.
If you have the Monroy tanks (as you probably do if the aircraft was ferried across the Pacific to Oz) and started with them full to the brim, running LOP then you probably landed still carrying plenty of fuel after 1200 miles!

Glexdriver,
your wife wanting a Cirrus is definite grounds for divorce ;-)
It would be a fairly straightforward case of intolerable cruelty.

SB

[IO540]

Nice trip, Ovation :ok:

6hrs19. My longest is 6hrs50 (TB20).

Judging from the GS reaching 225kt, you must have had quite some tailwind - otherwise that is an impressive TAS!

[glexdriver]

I was doing some planning simulation, and it look like really difficult to fly in these time of the year without a FIKI certified aircraft. So I think that the option is reduced to Mooney or the TB-20.

[IO540]

really difficult to fly in these time of the year without a FIKI certified aircraft

It depends on whether you need the ability to depart/arrive in thick cloud conditions, say 5000+ ft of icing conditions.

[dirkdj]

Have you looked at the Beech G36? It can be ordered from the factory with FIKI TKS, can be turbonormalized (with gross weight increase to 4000lbs), tiptanks can be added. Its handling is one of the nicest, it's well built, can go to major airports maintaining 150 kts on the glide or it can slip into small grass strips.
It has a large cargo door, excellent visibility.
You could also pick up an older A36 and fit all these goodies.

[IO540]

I recall looking at an A36 back in 2002 when I was in the market. Don't remember the details now, but think that fuel flow might have been a factor. What does an A36 draw, LOP, for 140kt IAS, say 5000ft, ISA?

[dirkdj]

IO,

I usually run about 46lph, LOP at 2200 RPM, WOT. Mine is normally aspirated, Saturday flew to EDNY and return on standard fuel, One hour plus remaining on landing. FL090 going and FL100 return. Dropped off my friend's A36TN to be fitted with TKS at Air-Plus (official TKS installer for this area). He flew at FL190, burning 15 US GPH and over 200 KTAS (go-far mode at 2200RPM). He burned more fuel than I did.

When retrofitting TKS to the BE36 you have a choice of FIKI or non-FIKI, the difference is in the paperwork, price and second fluid pump.

[IO540]

Dirk,

46LPH in which conditions and what IAS?

[mm_flynn]

In my TNA36, I would typically see 175 knots TAS on 14 gph @ 10k and say 3-5C. The TB20 has got to have better economy given you aren't dragging around a true 6 place aircraft.

[IO540]

175kt TAS at 10k on 14GPH is not bad for a substantially bigger plane. My best economy cruise at 10k (wide open throttle, 25LOP) is 9.0GPH which gives 140kt TAS which is 1.24 times better MPG. But at 140kt TAS you would be doing better MPG anyway.

Back in 2002 I was comparing data sheet figures and thought the A36 was about 1.5x worse than the TB20. But clearly that was wrong.

[cvlux]

Hi,
me too I had these type of question.
If you want FIKI you have just an answer: Mooney. Which one is your choice. But you have to remember that above 180 you need masks and they are oxygen hungry.
If FIKI is not important than cirrus and the cessna 350/400 are quite interesting.
Here too, you have to choose between turbo or not.
I have choosen the 400, but nevertheless I didn't spent so much above 180.
Good thing of the cirrus is that you have a big oxygen bottle (77 cu.ft), bad is the garmin 430,have you even tried to insert a a flight plan in it??
Good of the cessna is the garmin 1000 with the ready pad. Bad the 42 cu.ft. oxygen, this means that you need some kind of oxygen saving device.
last but not least handling. The cessna is utility certfied. Both have the side stick, but cessna behave more straight forward.

[vanHorck]

if you want to limit the oxygen with masks go for the Mountain High 02 system. It is pulse, not continuous, and so a small bottle lasts very long!

I use it and I am very happy with it!

[IO540]

I don't think Mooneys are the only SE planes certified for flight into icing conditions.

Also there are no apparent regs on masks above FL180 if one is using portable oxygen systems. In fitted oxygen systems you are legally required to follow the flight manual supplement on the system, but there is no such reg covering portable systems. There may be one but when a year or so ago a colleague and I did a detailed comparative airborne test (FL180) of oxygen demand delivery systems (basically, Mountain High and Precise Oxygen) versus constant flow options, we could not find such a "must use a mask above FL180" reg for portable systems. I have the writeup if anybody wants it.

I've been to FL200 using a cannula and it was perfectly fine. Blood o2 at 95% or so. One just needs to be careful with one's breathing (do not stop, obviously) and it raises issues with close supervision of passengers especially children. If you are at FL250 with cannulas and somebody starts to breathe through their mouth rather than nose, they will soon (within tens of seconds) be pretty unwell.

The value in an unpressurised plane which can go to say FL250 is that during the 1-5% of flights when you need to go that high to remain above the muck, you can do it. (The actual % will vary on your attitude to stuff like flying through frontal weather.) But you won't go that high (unpressurised) for any other reason; oxygen refills are a major hassle in Europe and even on a turbo engine the MPG won't get much better above FL200. Non-turbo, best MPG is c. FL080-100. I fly a TB20 and if IFR will always cruise at FL100 and climb only if needed to remain VMC on top. In Europe, tops rarely exceed FL160.

[cvlux]

the TB20 can be fiki but I don't think on N- register.
About the masks, the flight manual of the columbia 400 say that canulas are allowed up to 18.000. I don't know about other airplanes.
Me too I try stay around FL10, but sometimes it is no enough (alps or RAD restrictions). I agree with IO540 to refill oxygen in really a pain.

[172driver]

About the masks, the flight manual of the columbia 400 say that canulas are allowed up to 18.000

Could that have to do with the US airspace being Class A above 18000ft ?

[IO540]

I did wonder about that, but I think probably not. I think somebody decided that 18k is the figure above which if your nose breathing gets a bit lazy then you might "run away down hill" mentally before you realise something is wrong.

At say 16k you just feel knackered and maybe get a headache after some minutes.

But at 20k you have to breathe quite deliberately - I've been there. I have not tried this at 25k (would need a better plane) but it would be pretty tricky, not to mention serious passenger supervision issues.

I've done an hour at 20k and a number of 4-5hr bits at 19k, with one passenger.

Then you have a large spectrum of human fitness, ranging from unable to read the altimeter at 12k (been there to see it) to superhuman types who climb mountains without o2.

I think 18k for cannulas is probably right, 20k if you know what you are doing and you have an adult passenger who does likewise.

The o2 flow rates are also a bit high at high levels and oxygen becomes a real flight planning issue on long trips away - because one cannot bank on getting any refills.

[Tester07]

Is it not that the FAA advice is that one is susceptible to decompression sickness above 18,000ft, regardless of whether or not you are breathing oxygen?

[S-Works]

Only if rapidly decompressed. Un-pressurised flight carries a very low risk that increases slightly as you ascend and usually will have had another trigger to cause it.

To put it in context, ascending from a depth of 3m to the surface while diving is the same pressure change as the surface to 18,000ft.

The reason that 18,000ft is given as the threshold for use of cannula is that your nostril area does not provide enough volume flow for inspiration of sufficient O2 for efficient gaseous exchange to occur. This is exacerbated by the fact that you will be talking etc and so end up starved off oxygen. Going onto a full face mask allows a great tidal flow of oxygen to be taken in through both the mouth and the nose. As altitude increases further the lungs no longer have enough dwell time for gas exchange to occur and forced oxygen breathing systems then kick in.

It is nothing to do with experience or knowing what you are doing as has been suggested. Neither will you begin to feel 'unwell'. Hypoxia is an insidious killer and generates feelings of Euphoria and well being not of illness. I have some interesting video of chamber trials that we have done over the years testing various bits of life support kit. The test subjects were adamant that they were in control at all times and were not feeling the effects of hyoxia. The video evidence to the contrary is quite enlightening.

I would caution those who are planning on the high altitude use of oxygen to seek training in the physics and physiology rather than accepting the word of internet posters on what works. I would also be very disinclined to trust a finger oxymeter for accurate O2 readings at those altitudes.

I've done an hour at 20k and a number of 4-5hr bits at 19k, with one passenger.

I thought the FAA mandated FFM above 18,000ft?

[IO540]

Is it not that the FAA advice is that one is susceptible to decompression sickness above 18,000ft, regardless of whether or not you are breathing oxygen?

It could well be among the volumes of "advice", though I haven't seen this one. I cannot really see the mechanism though. Also, when breathing oxygen, one is invariably flying a non-pressurised plane so a decompression is not likely.

But this stuff varies with individual physiology anyway.

There is no doubt cannulas do work just fine beyond 18k and one American mag did a test up to IIRC 25k and found them fine. The problem, which I have found myself, is as I said above: if your breathing gets lazy then you could have a problem and that problem (loss of useful consciousness and thus the ability to do something about it) rapidly gets worse as the altitude goes beyond around 18k.

[IanSeager]

I would also be very disinclined to trust a finger oxymeter for accurate O2 readings at those altitudes.

Is there something better?

Ian

[Fitter2]

Cannulas work fine at FL240 with the MH EDS system, and if you don't make a positive inhale for a few seconds the system beeps at you. Experience in a 35 h.p. single enginred aircraft, but I have to confess the engine wasn't running on that occasion above FL 35, relying on free meteorological climb for the other 21,500 ft.

I am told the finger oxymeters are temperature senstive, so if you start to get frostbite they are iffy, but wear warm gloves and they are OK. I have no first hand knowledge. Also, for some reason, US suppliers won't ship to a UK address.

[Cobalt]

I thought the FAA mandated FFM above 18,000ft?

So did I. But all I ever found were certification requirements for aircraft oxygen systems. If there is an obscure regulation applying to portable systems I haven't been able to find it.

Of course it is hard to argue that you are prudent when flying significantly higher than 18,000ft with a cannula.