Refilling O2

I agree, Jesse, and yes if you use a constant flow o2 system (the oximiser cannula, typically, in GA) then the cylinder will empty completely if you forget to turn off the gas at the end of the flight.

But the context of this thread, AIUI, is whether welding o2 is the same as “aviation” o2, and we are talking about the big cylinders supplied from a welding shop or some such. These will never be returned empty. Example – the W size is common

I can fully see a Part 145 shop being prohibited from refilling a totally empty cylinder, but that is just the same as being prohibited from using a certain screw to secure an altimeter to the instrument panel if the bag which that screw came from doesn’t have a batch # which corresponds to a batch # on an 8130-3 form sitting in your filing system. It’s to do with approved process traceability. There is no actual danger in filling up a cylinder to 2000-3000psi if that cylinder has just been allowed to get empty recently.

Obviously nobody would fill a cylinder of unknown history, because it could be a 50 year old one picked up from a garbage dump. So there are limits to all this….

Maybe that is the context of the thread in which case it drifted dramatically from Stephen’s original question…ie how do you refill down route? I presume SW’s SR22 has inbuilt O2 so he can only refill at an airport…. I had exactly the same problem / question… I think the answer is that you need to get your aircraft tank filled at home and not plan on being able to refill down route…to get the most out of a refill the O2D2 system sounds like the way to go….

He didn’t ask about refilling at home, but with an inbuilt system scuba shops etc are not practical…you can make up a cascade system if you have access to the ramp/hanger with your homemade system….otherwise, if there is no on airfield service, or if it is at BJ prices, you can probably find a nearby gliding club where you can land and get a refill from their cart…

The only occassion I was ever able to refill enroute was a “very memorable” trip down to Crete where after a whole day’s running around in taxis I managed to find somebody in a scuba shop (no scuba shops on Crete did oxygen, apparently) who had a relative working in a gas factory in Hania, and they refilled my two little Aerox cylinders.

In fact that trip involved dealing with a number of difficult situations, of which being refused a landing clearance by Padova because they claimed I did not have Customs PNR, then getting shafted by Treviso who said they have avgas but “didn’t”

That trip, in 2007, taught me a number of “never do this again” things.

If I had an SR22 with the built-in system, I would get a refill hose for the bizjet oxygen refill trolley (likely cost of a refill €200+… I paid €200 in 2002 at Biggin Hill for a tiny cylinder) plus I would buy a portable system (the MH 48 cu ft cylinder, a 1st stage reg, and some oximiser cannulas, to keep it as cheap as possible) as well, and probably get the cylinder with a DIN thread to facilitate scuba shop refilling (which is likely to be a fraught process but you are unlikely to need it).

I don’t know how practical a gliding club refill would be if you can’t speak the local language. A scube shop at least has a tiny chance because they might get tourist divers.

Last resort is buying a small welding cylinder at some DIY shop. This would fit to a DIN MH regulator.

My cylinder lasts for 10 return trips to Germany. (I’m flying alone, sadly)

I don’t know how practical a gliding club refill would be if you can’t speak the local language.

Well luckily for me they speak English in Scotland where I’m based….I didn’t mean down route…I meant at home…. instead of paying bizjet prices or making your own cart…and avoid refilling when away by having an efficient system like O2D2

Really, the O2D2 is the best advice I have … I have the Cirrus semiportable system too and for two people in FL 160 it should last about 19 hours … much more than your average trip. I also don’t know about others – but when I fly south I use FL 160 to cross the Alps and then I descend below 100 … There’s really not so many days in Croatia or Greece in the summer on which you have to fly that high.

O2D2: Try to buy it in the US. I paid $ 800 instead € 1100 …

One thing to check about the O2D2:

I have recently received some disturbing emails from an O2D2 user, reporting that MH have had “software corruption” issues in this product (purchased in 2014) and it stopped working, and that this happened on two units this pilot had.

My two have been perfect but they were bought some years ago, and I am sure that whatever it is, MH will fix it. But it is worth checking before purchase that you are getting a fixed unit – another reason to buy direct from MH in the USA.

An interesting article about gas contamination:

http://www.apsf.org/newsletters/html/1996/summer/apsfmoss.html

And aviation specifications here

[above 1976 document stored locally and link fixed up – there was a strange problem with the site]

I have recently received some disturbing emails from an O2D2 user, reporting that MH have had “software corruption” issues in this product (purchased in 2014) and it stopped working, and that this happened on two units this pilot had.

That was us. We bought a O2D2 regulator directly from MH in May 2014. It was DOA.
We received another two units, which where DOA as well.

MH is checking each unit before sending it out, so in our case the units must have been damaged during shipping.
Engineering did wonder if while in shipping it was scanned with too much x-ray that may have damaged the processor,
but there is no way of knowing.

No chances were taken with the last unit we received. It was hermetically sealed.
Even the returned batteries where voltage checked. We received it in good order and we’re happy customers :)

MH gets five stars for after-care. Our bad luck must have cost them a lot of money, but they care a lot about having you as a happy customer…