Retesting and filling oxygen tank.

On Wed, 02 May 2012 08:44:16 -0500, lynn wrote:


So how about it you legal beagles out there--just
how does an aircraft owner get their oxygen system serviced legally?


Lynn, OK. I'll bite. I don't think I'm a "legal beagle", but I am a bit
of an FAR-nerd, so I'll expose myself to collective ridicule and attempt
to answer your question completely.

The first question to ask (as others have pointed out) is whether your
oxygen tank is considered (legally) to be part of your aircraft or not.
If the tank is not listed in your operating limitations section as a piece
of required equipment, and has not been included in any subsequent 337
forms as something that is installed in the aircraft, then it is not part
of your aircraft. In general, if something is not part of your aircraft,
then the FAA does not care about who inspected it or how it was inspected.

If it is not installed as a part of the aircraft but is carried aboard the
aircraft, then it is "cargo." The FAA has regulations about carrying
oxygen cylinders as cargo, but these apply to inaccessible cargo areas of
transport-category aircraft. So, on a private, Part 91 flight the FAA
does not care about what type of oxygen tank you may have aboard.

On the other hand, the Department of Transportation (DOT) does have
regulations about the transport of compressed gas cylinders. I am not an
expert on DOT regulations, but to my knowledge these regulations are not
specific to aviation oxygen (as opposed to any other type of compressed
oxygen). Therefore, any place (dive shop, welding supply shop, etc.) that
is certified to test and inspect compressed gas cylinders according to the
DOT requirements should be able to inspect and test your cylinder.

There is nothing "illegal" or shady about this. It's a DOT regulation, so
any shop that meets DOT requirements (see below for discussion of these
requirements) can legally certify your cylinder (whether or not it's used
in aviation).

If (and I highly doubt that this is the case with your Pik 20) the oxygen
cylinder is required equipment, then the manufacturer would be obliged to
publish inspection criteria and servicing instructions, and then you'd be
obliged to follow these procedures. In the absence of any specific
guidance from the manufacturer, the Aircraft Maintenance Technician (e.g.
A&P or IA) performing maintenance or inspection of the oxygen system would
follow the FAA's procedures as outlined in AC 43.13-1B "Acceptable
Methods, Techniques, and Practices - Aircraft Inspection and Repair". In
Chapter 9 this Advisory Circular describes how an AMT should inspect and
service installed oxygen cylinders, to wit:

9-51. SERVICE OXYGEN CYLINDERS.
REQUIREMENTS (Ref 49 CFR 173.34 e,
16). Standard-weight cylinders must be hydrostatic
tested at the end of each 5-year period
(10 years if it meets the requirements in 49
CFR 173.34 e, 16). This is a Department of
Transportation (DOT) requirement. Thesecylinders
carry an ICC or DOT 3AA 1800
classification and are suitable for the use intended.
Lightweight cylinders must be hydrostatic
tested every 3 years, and must be retired from
service after 24 years or 4,380 pressurizations,
whichever occurs first. These cylinders carry
an ICC or DOT 3 HT 1850 classification and
must be stamped with the approval after being
inspected. (Ref. 49 CFR 173.34 e, 15).

Note that the FAA's guidance refers to 49 CFR which is the Transportation
code. The rules in 49 CFR 173.34 are pretty long, but your question
concerned who can do this inspection, not necessarily how it is done, so
I'll dispense with quoting the "how" and focus on the "who". 49 CFR
173.34 (e) (2) (i) says:"

"No person may mark a cylinder with a test date or retester identification
number,or otherwise represent that a DOT specification or exemption
cylinder has been retested under this section, unless that person holds a
current retester identification number issued by the Associate
Administrator for Hazardous Material Safety and operates in compliance
with the terms of the retester identification number issuance letter."

So, to finally answer your question of "how does an aircraft owner get
their oxygen system serviced legally?" I can offer this explanation. If
you have an installed oxygen system, all servicing must be done according
to the manufacturers instructions and/or AC 43.13-1B. 43.13-1B says that
the testing and marking of these cylinders must be done according to 49
CFR 173.34, which in turn specifies that the hydrstatic testing and
marking can only be done by someone who holds a current retester
identification number. So, the AMT would be obliged to take the cylinder
to someone who holds this retester identification number. This could be
an aviation-specific shop, or not. As long as they hold this
identification number and are operating under the terms of the issuance
letter for this number, then they can certify the tank. Your A&P would
then note this inspection in the aircraft logs, and everyone is happy.

On the other hand, if the oxygen system isn't an installed system, then
there is no legal requirement under the Federal Aviation Regulations
(anymore than there is a requirement for you to inspect a duffel bag or
any other item of cargo). However you still need to comply with 49 CFR
173.34 since the tank will be carried aboard an aircraft as cargo. In
this case, you should seek out someone who holds a retester identification
number as prescribed in 49 CFR 173.34 (e) (2) (i) and ask them to inspect
and certify your tank. Then, you're good to go.

I hope this is "legal-beagly" enough.

--Stefan


--
Stefan Murry