medical oxygen question

[slowto250]

Hope someone with current knowledge of 121 regs can help with this one. My mother who is on medical oxygen at her MD's insistence, was refused boarding with her small carry on size bottle. She was subsequently informed that if required, the airline would have to supply it, and she would be charged 100 dollars per flight segment, for it's use. Does anyone know if carrying portable oxygen on board is governed by 121 regs, or is it governed by individual company policy ? I am familiar with 135 regs regarding this, but evidently these rules do not apply to scheduled 121 ops. Thanks for any input.

 

[Dangerkitty]

Hope someone with current knowledge of 121 regs can help with this one. My mother who is on medical oxygen at her MD's insistence, was refused boarding with her small carry on size bottle. She was subsequently informed that if required, the airline would have to supply it, and she would be charged 100 dollars per flight segment, for it's use. Does anyone know if carrying portable oxygen on board is governed by 121 regs, or is it governed by individual company policy ? I am familiar with 135 regs regarding this, but evidently these rules do not apply to scheduled 121 ops. Thanks for any input.

From what I remember it is governed under part 121 regs. After the Valujet crash airlines really got very strict in regards to flying with O2. I have had to deny boarding passengers many times in the past because they didn't follow company procedure and have the airline supply the O2.

 

[Cardinal]

The short version? No you can't provide your own oxygen. FWIW, my carrier will not provide it either, so you'll just have to walk. I s'pose that'll build lung capacity, anyway.

121.574 Oxygen for medical use by passengers
A certificate holder may allow a passenger to carry and operate equipment for the storage, generation, or dspensing of oxygen when the following requirements are met:
(1) The equipment is-
(i) Furnished by the certificate holder
(ii) Of an approved type......
(iii)Maintained by the certificate holder in accordance with an approved maintenance program......

(4)...medical need to use it evidenced by...a written statement....signed by a licensed physician...

 

[mike1mc]

Dangerkitty is correct. The 135 reg refers you to Part 121. Technically speaking, you can bring your own oxygen, but the regulator needs to be DOT/FAA approved and maintained before it can be used on a commercial flight. The other half of this discussion should include the HazMat Regs (HMR175?). We have denied a few passengers boarding on 135 flights because of the oxygen requirement. We now carry a portable bottle with 4+ hours duration for pax use just in case.

 

[Whiskey Tango]

The thing with the O2 bottle is if there was a decompression or even just the normal change in pressure during a flight the regs require that the bottle is test for such and will not blow up.

 

[qmaster3]

The short version? No you can't provide your own oxygen. FWIW, my carrier will not provide it either, so you'll just have to walk. I s'pose that'll build lung capacity, anyway.

And she'll get there faster

 

[avbug]

During a cabin decompression, an O2 cylinder is not going to explode or burst. The aircraft is holding only a few pounds of differential pressure per square inch (psid); let that go, and the eighteen hundred pounds of pressure in the cylinder isn't any less secure. The notion that an oxygen cylinder will burst at altitude during a cabin decompression is laughable.

 

[TonyC]

During a cabin decompression, an O2 cylinder is not going to explode or burst. The aircraft is holding only a few pounds of differential pressure per square inch (psid); let that go, and the eighteen hundred pounds of pressure in the cylinder isn't any less secure. The notion that an oxygen cylinder will burst at altitude during a cabin decompression is laughable.

I agree that the notion of an oxygen cylinder bursting during a rapid decompression is laughable. However, the suggestion that there is only a "few pounds of differential pressure per square inch" is misleading. An aircraft operating at FL370 with a cabin at, say, 8,000 feet will have a differential pressure of roughly 7.6 psid.

Apart from the explosion (non-)issue, I would think there are more delicate components in the portable oxygen system that might be susceptible to damage during a rapid decompression. Additionally, it would need to be capable of delivering adequate oxygen at much higher altitudes than we normally walk. If I were the FAA, I would be concerned that the pressure regulator was capable of continued operation after such an event. Joe's Hospital Supply doesn't have to worry about such environmental stresses on his rental equipment, so it's not likely it has been so certified. His regulator and mask might be quite adequate at normal altitudes, yet be unsatisfactory in delivering oxygen when the altitude suddenly climbs to FL370.


Someday when you get bored at altitude, you should try calculating the force working outward on that piece of glass next to you.

 

[avbug]

Reduced external pressure has no effect on a pressure regulator; it's dealing with pressure on the pressure side of the diaphram in the regulator assembly. Usually this opposes a manual valve against spring pressure, with what's in the cylinder. A drop in external pressure to zero, or even a vacum with neither affect the operation of the regulator, nor have any tendency toward causing the cylinder or the regulator assembly to burst or fail.

The capability of the system to deliver oxygen at altitude is only restricted by the oxygen delivery vehicle; the mask. The tank and regulator merely deliver, and altitude doesn't change that fact. Most medical oxygen is delivered in portable units via a nasal cannula at the maximum rate of 6 litres per minute. This is insufficient in flow rate, and the delivery vehicle, for use at altitude, but it's better than nothing.

However, that's all irrelevant. The purpose of a portable oxygen system for medical use is supplementary in nature, and is not intended as a sole life-sustaining source at high altitudes.

The FAA is not concerned with the ability of the regulator to deliver oxygen during an emergency cabin pressure loss. The FAA's sole concern is the carriage of oxygen in the cabin as a hazardous material. The only concern is the safety of the equipment. A maintenance program for a cylinder includes assurance of a purged and dry cylinder prior to filling, and regular hydrostatic tests at intervals determined by the type of container. The FAA is also concerned with carriage and protection of the regulator assembly as the weak link that can be damaged. If damaged or broken while the valve is open, the tank becomes a missle with great potential for injury or damage.

Bursting at altitude or the ability of the regulator to deliver a medically supportive oxygen flow is entirely irrelevant to the requirements of the regulation, or the maintenance programs that the regulations require.

 

[troy]

the O2 cylinder that the airline supplies is "up to their standard" in terms of how well protected the bottle neck/regulator is. Another words, if dropped, it has a less likely tendency to break (simple liability issues) The tank/regulator/associated equipment is the same as one would buy off the street. (same issue as the Faa approved landing light vs. the automotive store light)

 

[Dr Pokenhiemer]

Now you guys are making me worried about a decompression in my air ambulance!!! We have the main takn under the stretcher and a couple of spare tanks. KA-BOOM!?

 

[avbug]

No, no kaboom. Pressure cylinders are required to undergo hydrostatic testing regularly, depending on the type of material and any specific manufacturer recommendations. Generally steel cylinders are on a five year hydrostatic test requirement, while carbon fibre and lightweight cylinders go on a three year cycle. You can check for this date on the cylinder itself; it will be stamped into the neck, and each subsequent test date will be stamped there.

Airlines do not choose their oxygen equipment because it's somehow tougher and able to be dropped. The requirement that an airline use their own equipment is because it's been under their approved maintenance program and control; it's a known quantity and quality. There is no determination made or able to be made regarding a foriegn or unknown piece of equipment brought on board. You could check the hydrostatic test date, but you have no way of knowing if the cylinder has been purged with each filling, how many fillings it's had, or it's maintenance or history life. You have no way if it's been kept dry, or if it suffers internal corrosion due to moisture from improper filling or storage.

Your King Air probably uses a standard steel E cylinder under the litter. The risk of the cylinder exploding is a non-issue. With oxygen cylinders, you should be far more concerned about the regulator attachments. Break these and the cylinder may become a missle with a mission. Your smaller portable bottles, often stored at the back of the airplane to use when onloading and offloading y our patient, are a far greater potential for damage, especially from dropping.

You're probably already familiar with the requirements to crack the valve slightly and open it slowly, to never position yourself over or adjacent to the valve, to refill it slowly, to avoid proximity to petroleum products (which can self combust in the presence of pure oxygen), etc. These are far more important to your longevity than wondering if the cylinder is going to go kaboom. It isn't.

 

[Dr Pokenhiemer]

Thanks Avbug, but I was just being a little sarcastic. We have an H-tank on the Lear. The drawback with having such a large tank back there is that when my medical crew gets in a farting contest, they have more O2 back there than I do in the acft tank up front!!

 

[Well-hung Start]

there are 3 kinds of "oxygen"

Dudes:


The aviation field has a history of being clueless about oxygen. I remember a ridiculous assertion from an "authority" that "welder's" and "medical" oxygen are different from "aviators" oxygen.

Oxygen is O2 no matter whether you're fusing steel, rapidly decompressing, farting, or having chest pain. And the physics of compressing it into a tank at 1800 psi is identical: it must be PURE and it must be DRY.

So bite me! Or breathe me! Whatever!

one last note.....The most probable mechanism-of-injury from an oxygen "bottle" (over-engineered steel vessel) is DROPPING IT ON YOUR TOE.

 

[cvsfly]

Pardon my cluelessness. We have always been told that the differance between medical and aviator O2 is the moisture content. Aviator's being drier due to freezing concerns. It makes sense to me that filling any tank you would not want moisture in it. Where is the moisture added to medical O2? For those 135 operators that do accept passenger carry-ons in accordance with 135.91(a), what documentation do you ask for to conform with 135.91 (a)(1)(i)?

 

[avbug]

Until Mr. well hung jumped in with his outfield bite-me comments and introduced the topic of mositure in 02, it wasn't part of this thread. However, now that it's been brought up, all 02 is indeed the same. In medical oxygen, moisture is introduced during the 02 flow to the patient, usually at or after the patient regulator.

There is absolutely no difference between welding oxygen, medical oxygen, or aviators breathing oxygen, except for price. There is no difference in purity or moisture content. Only price. All three products come from exactly the same source, and are exactly the same product.

 

[Well-hung Start]

Avbug is right

Well-stated, Mr. 'bug.

But your final incisively-distilled definitive authoritivity seems to have ended the thread.

I want to keep it going, since this is the only aspect of aviation I always get the right answers to!

Any other Oxygen questions out there? Comon!

 

[A Squared]

Here's a link to an article which discusses the oxygen issue in a little more depth.


http://www.avweb.com/news/columns/182079-1.html