Oxygen in a Mooney

Oxygen Overview

The use of oxygen is a personal preference for flights below 12,500 (a simplified view).

However, with Mooneys that can travel four hours at 10,000 feet, there is merit to review the need and use of oxygen at altitudes below 12,500.  For pilots who use supplemental oxygen, the reports are that they arrive at their destination in good health (and not feeling tired, nauseous, with headache, or achy)

One Pilot's Summary View:

I fly with o2 about 75 percent of my flight time. I am less tired, fewer headaches and fly better.  I have learned a couple of things. I started by purchasing a pulse Oximeter from rite aid for $50.  I commute to a job site and have to go over mountains with a minimum ifr altitude of 16k so I could compare my blood oxygen level each week. If I was short on sleep or tired levels would be low. I think that caffeine also had an impact but several doctors I queried said they knew of no research on caffeine and blood oxygen levels. Due to COVID there is now a lot more information on blood oxygen levels but I have used <90 as the low limit redline. Most doctors will tell you that your blood oxygen level should be the same at altitude as at sea level (or your home elevation). Bottom line every human has a different capacity to maintain their blood oxygen level. I learned that my body does not cope as well with altitude as some of my friends. 

How to carry a o2 bottle in a plane.  A compressed gas bottle is heavy and solid. In turbulence that bottle can cause real damage and or injury. Most every pilot with hours in the book can tell you about the clear air turbulence that smacked them. I know as I put a dent in my prior planes plastic headline on approach to van nuys airport. I now fly with my seat belt a lot tighter!  The o2 bottle must be secure! This is not an option but a basic safety item. Seat belt strap harness, floor clip ( I made a pair of clips that attached to the pilots seat rails behind the seat). About the most dangerous thing you can do is have the bottle loose on a seat. Ask yourself: are you willing to have that bottle hit you in the head or hit one of your thin plastic windows?  I am not. Lastly if you you are not yet convinced, look at the physics. My o2 bottle is filled to just under 2,000 psi when full. Now if the valve is damaged that bottle becomes a compressed gas rocket. Google welding gas tank accidents and learn how many miles the bottle can travel. Seems like a really bad idea to carry an unsecured bottle in a vehicle which can have unexpected turbulence. Nuff said. Do not do it

since I need less stuff to fool around with while flying I use a headset mounted boom nose cannula. I swear by this thing mountain high sells it for a hundred bucks and it is part of my engine run, pre takeoff: boom cannula in and o2 on and focus on flying not groping around the back seat to turn on o2.  While I want to simply have the o2 system active and available I learned a lot about passengers from my o2 use. Let’s say I was flying over the Sierra at 12500. In the old days I would look at altimeter, loosen my seatbelt ( bad idea in the proximity of mountains) turn on o2 and then take off my head set and wrestle the o2 hose into place while missing radio calls from Oakland center. My passenger would assume the flight just became a lot less safe. Questions would start to fly and passenger comfort goes way down. 

So it’s clear I am on o2 a lot. I’m here to tell you a portable o2 bottle hold very little o2 when supplied with a fixed (but set by altitude) regulator.  So the next thing I learned is how expensive it is to buy o2 on the road. Most FBO charge at least $50 to $75 to refill a bottle. A lot will only do it when a mechanic is available which is a huge hassle. So I bought a mountain high pulse delivery box. This gizmo delivers o2 only when you inhale. The standard regulator is busy emptying your o2 tank the second you turn it on. Not the pulse demand. I can now fly at 15k from San Francisco to Boston and return on the same bottle that used to only get me to the Mississippi River. The bad news is the pulse demand box costs $800. My hanger neighbor found a non aviation home medical version for about $300 I think it is a more primitive device and it is single port. No passenger hookup but he likes and uses his. This device means I am no longer limited on my o2 use so I turn on the o2 prior to take off and turn it off after landing   

Reference: Posted November 25, 2020

Oxygen Tanks - Aviation store

Tanks come in several standard sizes with the larger tanks lasting longer.  A search at Sportys.com will lead to a system that can be purchased with minimal research, but at a premium (link to mooneyspace).

Commercially available tanks

If one completes a search on amazon, the following can be found:

• Medical Oxygen Cylinder with... - a standard medical cylinder.

• Medline HCS8725M Mini Oxygen... - A single point regulator for a standard medical cylinder.

• HOUDELL High-Flow Soft Oxygen... - this is a standard oxygen mask

• Dealmed Non-Rebreather Oxygen Mask, Adult, 5 Count - this is the canalus type breather

Reference: Posted June 8, 2020

Other purchasable items

125 cu ft Oxygen Tank - delivered full

CGA 540 male to CGA 870 - connection refill hose

CGA 540 and CGA 870 Explained

Medical regulators use a CGA 870 connector, commonly called a post-valve (because it's a valve on a post, I guess?).  Most supply shops will require a prescription, and they won't refill them--they simply take yours and give you a new bottle of the same size.

If you use a medical bottle with a CGA 540 valve and regulator, you should not need a prescription, although you will confuse the heck out of some people.  A couple times at my local welding shop, somebody has insisted I need a prescription, then somebody comes up and points out the CGA 540 valve and says I'm good to get it refilled.  If you want to avoid questions, tell them it's for a fish tank or brewing or something.

Do note that most non-aviation flow regulators are labelled for liters per minute flow, but they are actually pressure regulators.  That means at altitude, those numbers can be completely inaccurate.  You will need a separate flow meter and pulse ox to verify you're getting enough oxygen.

Reference: Posted March 19