I think it is a law requirement to use oxygen masks above 18000ft.
Only in the FAA FARs which do not apply to EASA. I have used O2D2 with cannulas up to FL250 and it's reliable and comfortable. I would never use a mask but I do carry one which I can connect directly to the builtin system in case the O2D2 fails.
Peter/achimha , When you use the O2D2 with cannulas at FL250 do you have to change the setting in the O2D2 to a different setting. (The Setting for masks)
I am using the O2D2 regulator with cannulas up to FL250. I put the regulator on F5 (face mask mode) and it delivers more oxygen. I have a facemask standby and I don't do this with passengers in the back which I cannot monitor.
Thanks for the information, I am going to try and find a system to rent for a week or so before buying, just to make sure that I and the a/c are happy at those levels, since owning the Seneca I have flown mainly at FL100.
I use the O2D2 on the standard cannula setting, to FL190, but on a FL200 flight I did as Aeroplus and went to the Mask setting.
FL250 - wish! I would need 15:1 pistons to do that
If your Seneca is turbo it should do FL200 easily, otherwise maybe... what model is it? Maybe others here can input on likely performance.
Oxygen is the best "small money" spent in aviation
Even at FL100, I use it 100% of the time and I arrive awake, instead of shagged...
It's a 1981 Seneca 3, it did have built in oxygen bet the bottle and regulator were missing when I bought her. So my thought are for the O2D2 and the CFC 048 which should give good bourses for 2 people.
Even if the Seneca had builtin O2, I'd get the O2D2. It is so much better without the constant fly of dry and cold oxygen. I have builtin oxygen and only use it with O2D2.
I don't fly anymore without the O2D2 regulator. It "feeds" 2 people per O2D2 regulator, so I use it in the front and with passengers in the back I have a mixed environment with constant flow regulators in the back. See here my article on using oxygen with some pictures of the setup.
Don't forget to buy something to measure your oxygen saturation level while in flight.
I see you mention the Oxyarm cannulas, Aeroplus.
Are they any good?
I can't see how they can work well, given they don't go up into your nose properly and must waste most of the gas. They may be OK for a wasteful constant flow scenario...
I like the Oxyarms. It is a close you can get to flying a pressurized aircraft. But, it is true that the Oxygarm is not as accurate at "aiming" the oxygen in the nose as is a regular "cannula".