high altitude single engine
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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.
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.
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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!
I use it and I am very happy with it!
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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.
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.
Last edited by IO540; 24th Dec 2008 at 19:55.
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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.
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.
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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.
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.
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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 thought the FAA mandated FFM above 18,000ft?
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.
Last edited by S-Works; 30th Dec 2008 at 16:15.
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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?
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.
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.
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.
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Originally Posted by bose-x
I thought the FAA mandated FFM above 18,000ft?
Of course it is hard to argue that you are prudent when flying significantly higher than 18,000ft with a cannula.
