Oxygen charging in the hanger

[allthatglitters]

We recently had a debate about charging aircraft with Oxygen in the hanger, Various people argued for and against it, in the end we went to the aircraft manual's of the types operated and found no mention.

[WJman]

Do you mean charging portable and crew O2 bottles. If so, why not. As long as you have a dedicated oil and contaminent free room, with the proper regulator's and preferably an oxygen bath or contaimnmet unit why not.If it's is done properly it is safe and quick.

[Golden Rivet]

Lots of companies, mine included, have banned all forms of oxygen charging.

[WJman]

Is this in the UK? Why have companies banned O2 charging. I understand the risks but as long as safe precautions are followed it would be no more dangerous than countless other tasks we perform that are dangerous to a certain extent.

[Blacksheep]

Back in RAF days we used Liquid Oxygen instead of gaseous - even including the military VC10s. The vapour coming out of the vent during Lox charging was just the job for fast chilling a Coca Cola can out East (or even in UK during the summer) Much ado about nothing I think. Oxygen charging is as safe as refuelling as long as you do it by the book.

[HiSpeedTape]

The rot was started by the yanks. F.A.R something or another which prohibited in-situ servicing of oxygen systems. So for some unknown reason we have decided to follow suit and now have to remove the bottle from the aircraft and send it away for replenishment.:yuk:

[Milt]

Fire is the risk.

ANY grease or oil in the presence of high pressure oxygen is a certain fire lighter.

May be there are a few other substances which will burn spontaneously in the presence of pure oxygen. What about human body oil? Anyone know?

So how about a few actuals described for our benefit.

[spannersatcx]

HSE on O2 (http://www.hse.gov.uk/pubns/hse8.pdf)

[Mr @ Spotty M]

My company allows charging in Hangar if charging is listed in AMM and if not, the bottle is removed and a replacement fitted. Cabin portable bottles are replaced and recharged in our workshop, where an area is set aside with its own equipment.

[gas path]

We charge the O2 systems in situ, but not in the hangar.
Personally I don't see a problem with charging in the hangar, the procedures we have are robust enough.
Portable O2 bottles are sent away.

[ukeng]

I think it's a company thing, some don't like it being done in the hangar for insurance reasons - if it does catch fire it's better that it happens outside.
Portable oxy cylinders get sent away in our firm.

[allthatglitters]

Thank you for your responses.
Sorry, I should have been more specific, it's the charging of fixed oxygen cylinders, were the aircraft is fitted with the pipe work for toping up.
The aircraft without this provision and the portable bottles are also sent away for topping up.
A previous company I worked for in the UK, wouldn't allow us to charge O2 in the hanger.

[Krystal n chips]

I can see the arguments for and against here--and personally I would, and have been, more than happy to replenish the system in a Hangar---if you follow the basic and well established procedures the process is safe enough after all. My concern about removing a bottle is that you are opening up a system with all the inherent risks of ingress and contamination. Likewise, the removal --transfer to a bay--replenish-- test--certify--etc all adds to the overall cost for a simple replenishment in-situ. I can see the response about one fire etc. is more expensive---but I feel the O2 incident statistics would not support this. At least from what I can recall that is. Anybody know the last major oxygen incident that caused a hull loss ?.

Milt--you raised an interesting point about body oil etc---I am sure the RAF did an investigation along these lines a few years ago--but can't recall the findings. And on a personal level, I have always thought LOX was more hazardous than gaseous oxygen anyway.

[Blacksheep]

The Vulcan B Mk2 strategic (nuclear) bomber had a Rover Gas Turbine Airborne Auxiliary Power Unit (AAPU) In flight it was started by firing a pyrotechnic starter cartridge through the compressor to spin it up, then discharging oxygen directly into the compressor while applying fuel and ignition. The oxygen charging point and the oil filler cap were co-located under the same access panel, with the two charging points being about four inches apart. The Vulcan B Mk2 remained in service for more than thirty years and despite the AAPU oil and oxygen being replenished on every pre-flight and daily check, not once did we ever have an oxygen fire or explosion due to this arrangement.

As I said earlier, 'Much ado about nothing'. Oxygen charging on the line or in the hangar is perfectly safe as long as you follow the laid down procedures.

[knightdriver]

its not allowed to charge any o2 bottles at turkish airlines we use readly charged o2 bottles.

[gaterbait]

On our USAF aircraft we service the LOX system outside but we service the portable bottles on board.