Overwhelmed by Oxygen Choices

Basic option is to use Aerox oxysaver cannula. These are the mustache reservoir that helps conserve oxygen between breaths; pendant is same idea in a different package. It allows you to keep flow rate lower while the mustache reservoir is filling for "bigger" inhale of oxygen. I'd recommend the one where the needle flow valve is incorporated into the flow meter. You keep it in your lap and it's easier to see and adjust from in front of you rather than needle valve on the scott connector.

If you fly in the levels and on oxygen regularly or fly with multiple pax on oxygen (or don't have somewhere locally to fill oxygen easily), then it makes sense to move to a pulse demand system. Either the Mountain High O2D2 or the Precise Flight X3 Demand conservator. Both have their pros and cons. Some Mooney pilots have difficultly with the onboard altitude compensating regulator "powering" the O2D2. I have the MH EDS O2D2-G2 and like it. But there's more cost in start up, batteries and more tubes, and different set of failure modes you have to consider.

If you buy a system, I'd get at least a 2 place system. I'd rather get the O2D2 than the O2D1. You don't have to use #2, but when I have a pax/copilot I'd rather have it. I like the pulse demand as it dries my sinuses out less, lasts longer between fills, and I find the puff of oxygen reassuring. But I fly with others with the Precise Flight X3 and they like it as well and like that it doesn't need batteries.

I think that the pulse demand systems really shine for those who fly frequently in the high teens/flight levels with a turbo. If you're using a face mask in the flight levels you'll go through a tank more quickly. But before you buy a $400-500 face mask with mic, make sure you have decided which system you're going with. The masks aren't interchangeable and Mountain High mask will not work with Precise flight.

My personal advise...if you aren't sure what you want/need, get the oxysaver cannulas and get a better feel for your oxygen needs, how long your tanks last, etc. THEN find other pilots with the pulse demand systems and see what you think. A great idea is go to Oshkosh EAA Airventure and demo both and enjoy a 15-20% on site discount for whichever one you choose!

**Marc_B** · June 7, 2024

@Max Clark This is what I started out with. SKU: 4110-704-3 https://www.aerox.com/4110-704-oxysaver-cannula-retrofit-kit-w-flow-meter-needle-valve/


I'd get at least 2 (pilot/co-pilot); or if you routinely fly with others needing oxygen, I'd get one for each oxygen connection in your aircraft.

I think the pendent may be a little more "aesthetic" without the mustache reservoir?? Not sure I've ever seen data on size difference of the reservoirs... But for those interested, here's a medical article comparing oxygen saturation and flow rate for traditional cannula and reservoir cannula. In this study same saturations achieved with 0.5 LPM with mustache vs 1.8 LPM with standard cannula. Meaning, go with reservoir cannula of some flavor!
https://pubmed.ncbi.nlm.nih.gov/3971765/

**Max Clark** · June 7, 2024

33 minutes ago, Marc_B said:

My personal advise...if you aren't sure what you want/need, get the oxysaver cannulas and get a better feel for your oxygen needs, how long your tanks last, etc. THEN find other pilots with the pulse demand systems and see what you think. A great idea is go to Oshkosh EAA Airventure and demo both and enjoy a 15-20% on site discount for whichever one you choose!

Thanks! I think I'll do just that.

**Max Clark** · June 7, 2024

28 minutes ago, Marc_B said:

@Max Clark This is what I started out with. SKU: 4110-704-3 https://www.aerox.com/4110-704-oxysaver-cannula-retrofit-kit-w-flow-meter-needle-valve/

I'd get at least 2 (pilot/co-pilot); or if you routinely fly with others needing oxygen, I'd get one for each oxygen connection in your aircraft.

I think the pendent may be a little more "aesthetic" without the mustache reservoir?? Not sure I've ever seen data on size difference of the reservoirs... But for those interested, here's a medical article comparing oxygen saturation and flow rate for traditional cannula and reservoir cannula. In this study same saturations achieved with 0.5 LPM with mustache vs 1.8 LPM with standard cannula. Meaning, go with reservoir cannula of some flavor!

https://pubmed.ncbi.nlm.nih.gov/3971765/

Thank you!

**M20F** · June 7, 2024

You will find that largely it’s not worth the hassle to fly above 12.5K in a NA plane (or in a turbo unless it’s a long haul). Yes an Ovation can do it, sure occasionally makes sense, sometimes out west you need it. For the most part though it ain’t worth the effort.

I would get a cheap cannula and mask to mess around with. After that you can go from there.

IvanP · June 7, 2024

When I bought my Bravo last year, I started using the Aerox Oxysaver cannula with the built-in O2 system (Scott connectors). Worked well as far as O2 sat levels are concerned, but O2 consumption was pretty high when flying above 15k. Added Mountain High O2D2 (usual mission is me and the wife) with in-line reducing regulator few months after getting the plane and have been very happy with it. We can maintain good sat levels and consumption dropped significantly. We usually start O2 at 8k and cruise between 12k and 22k, depending on winds and terrain. I have not been keeping a detailed chart of O2 consumption, but since the last time the tank was filled to about 1,300 PSI, I used O2 for about 30 hours (1 or 2 users) and the tank is now at about 300 PSI.

It is my understanding that the in-line reducing regulator is needed for the factory systems on Mooneys to avoid damage to the O2D2 unit. I do not know what setup Ovations have, but I have the factory installed altitude compensating regulator that came with 1990 Bravo. I recall reading posts on the forum that at least one MSer had issues with MH O2D2 and the factory regulator in a Bravo, but mine seems to be working fine. I also have a back-up SkyOx portable that I used in my E-model before getting Bravo.

wombat · June 7, 2024

Be sure you get the right connector for your plane. I think all of the permanent installs use the Scott connector.

This is what I bought: https://www.aircraftspruce.com/catalog/pnpages/13-18992.php

**Boilermonkey** · June 8, 2024

You might consider buying your own O2 refilling system. I bought a refilling system for $415 and rent two large aviation O2 tanks from Airgas. I spend about $300 a year on oxygen including the two tank rental rental. I use standard cannulas and masks for passengers who prefer them and don’t mess around with the oxygen saving cannulas, masks, or demand systems.

It’s simpler and in the end maybe even less expensive.

**Z W** · June 8, 2024

Started with the OxySaver Cannulas. They were fine. Went to the O2D2. Like it much better. Mostly because the oxygen tank now lasts so long, I use the oxygen more (any time over 8,000 feet or so) and arrive feeling much more refreshed and sharp. Don't have to hassle with filling the tank or getting it filled nearly as often - couple of times per year.

Also the headset-mounted boom cannulas are much more comfortable and convenient. All of the OxySaver style ones are always tangled up around your headset and uncomfortable to wear.

**Pinecone** · June 8, 2024

I am a huge fan of the O2D2. With the current version, you can run off a power cable to a USB outlet. And if it loses power, it auto switches to batteries. I have had mine for 2 years and have not changed the batteries.

As for O2 consumption, I have had the tank filled at the last two annuals. This is a 115 cf built in bottle and most trips are solo, with a few with 2 people.

**dkkim73** · June 8, 2024

My experience and understanding are similar to @IvanP's in terms of O2D2 specifics.

Went through this evaluation last year, though with a turbo so the eventual need was more definite. One thing I will endorse: Oxygen is useful at lower-than-required altitudes, maybe more so that you would think, and subjectively noticable, at least for me. So, while you might want to get a feel first with a passive conserver cannula, I think you'd find eventual utility in the conservers (unless you're always tooling around low across the flatland; I didn't see a homeport in your profile). So I think it's good you're looking at this for a high-performance NA aircraft as well.

I found that using the mustache OxySaver cannulas worked for me, but required a lot more oxygen flow/use to maintain similar sats than I later saw with the O2D2. Tank fills last a lot longer since I purchased a demand conserver. When I started looking into all the specific choices (# of setups, +/- mask, etc) I found the O2D2 less expensive for a 2-person setup than the Precise Flight X3 would have been. Pros and cons have been articulated before, but there seem to be enough PIREPs for each to conclude both are solid choices.

I was *very* hesitant to choose an electrical system over a mechanical, on general principles. One more thing with a USB cord (a dinky standard) or AA batteries, right? However, I've been very impressed with the practical simplicity of the system, and I've had zero issues. For me with the Scott/Avox onboard system, it works fine with the inline reducer. The company is very good to communicate with, they will walk you through the nitty-gritty details.

FWIW the Boomula option adds comfort and convenience in the cockpit. The flow sensing is very reliable with the prongs kind of just floating there in your nostrils. Easily maintains sats for me up to 17k so far. I don't have a detailed PIREP on the mask performance yet, just basic ops checking so far.

HTH

David

ETA: An issue with O2 fills is often that of logistics, more than cost. E.g. not available, late in the day, they don't have the right fitting for Mooney (happened 2x to me so far).

jlunseth · June 8, 2024

I have the Precise Flight simple system, tubing with a ball valve and the mustache cannula. I also have one miked mask. I have had several passengers on cannulas above 18k and none have complained. I used to use an oximeter routinely and so did the passengers, but eventually I found that looking at the ball valve once in awhile and correctly adjusting it kept O2 levels where needed, so I have not used the oximeter for awhile. I did not find that the mustache cannula was helpful. The ball valve has one scale for an ordinary cannula and another for the mustache (generally lower flow levels). The oximeter did not show that the lower flow levels were working. Others on this site have had a different experience.

I would contact Precise Flight and ask some questions before jumping in to the demand conserver. If you read the 231 manual you will see that it has a regulating valve in the built-in system that is more than just an on/off switch. It says that O2 will flow "appropriate to the altitude." This indicates to me that the valve in the aircraft increases or decreases the flow depending on altitude. The conserver also increases and decreases flow. So if it were me, I would want to know if the conserver expects a set flow once the O2 is turned on, and if the valve in the aircraft and the valving in the conserver might not cooperate with each other. I didn't get the conserver so I never asked the question.

My system is old enough now and has been used enough that one of the plastic hoses has cracked and needs to be replaced.

It is easy to disinfect the system after use. Isopropyl and Q-tips, I do it regularly since I often fly with compromised medical patients in the aircraft.

**AndreiC** · June 8, 2024

If I were you I would buy the simplest possible system first, and see how many times you use it in the first year. Then if the use warrants it, buy one of the more expensive systems. I live in the flatlands of WI, and for the first 20+ years of flying never used oxygen. Then earlier this year I wanted to go to the West Coast and do some flying over high mountains, bought a used Aerox tank with 4 OxyMiser cannulas. One filling of the tank was enough to take me to the West Coast + all the flying I did there (a couple of flights were with a passenger as well). Another filling was needed for the flight back. Total cost was $500 for the Aerox system, $30 + $50 for the two fillings. I still have a half tank left over, and I don't envision doing much high altitude flying soon. So there you have it.

**Max Clark** · June 8, 2024

23 hours ago, M20F said:

You will find that largely it’s not worth the hassle to fly above 12.5K in a NA plane (or in a turbo unless it’s a long haul). Yes an Ovation can do it, sure occasionally makes sense, sometimes out west you need it. For the most part though it ain’t worth the effort.

I would get a cheap cannula and mask to mess around with. After that you can go from there.

There’s a couple specific routes I’m looking at that will require me to fly 12k+

NA 550 - I understand the performance impact, just a requirement for where I want to go

**Max Clark** · June 8, 2024

9 hours ago, Boilermonkey said:

You might consider buying your own O2 refilling system. I bought a refilling system for $415 and rent two large aviation O2 tanks from Airgas. I spend about $300 a year on oxygen including the two tank rental rental. I use standard cannulas and masks for passengers who prefer them and don’t mess around with the oxygen saving cannulas, masks, or demand systems.

It’s simpler and in the end maybe even less expensive.

I’ve been wondering about this exact thing. Spending $2k on the demand reducers just feels like extra things to fail and a good chunk of money to spend

**N201MKTurbo** · June 8, 2024

I have a Precise Flight demand regulator that I bought on EBay for $25 from somebody that didn’t know what they had. It was listed under medical equipment. That was 20 years ago. It is still working fine. The passengers get conserver cannulas.

**Boilermonkey** · June 8, 2024

1 hour ago, Max Clark said:

I’ve been wondering about this exact thing. Spending $2k on the demand reducers just feels like extra things to fail and a good chunk of money to spend

Exactly. Buy yourself a system to refill yourself and you will spend less and not. Be so concerned about consumption or failures of the system.

**N201MKTurbo** · June 9, 2024

Check this out

https://www.ebay.com/itm/185700412359

**M20F** · June 9, 2024

16 hours ago, Max Clark said:

There’s a couple specific routes I’m looking at that will require me to fly 12k+

NA 550 - I understand the performance impact, just a requirement for where I want to go

Logically then do the math on how many times you do it and that determines if a $1000 conserver is worth it. You can fill up a lot for $1000. You won’t use very much O2 on a cannula flying 12-16K.

Illogically I have an X3 demand conserver but I like to buy stupid things for airplanes.

**LANCECASPER** · June 9, 2024

I have had the Mountain High O2D2 units with the inline reducing regulator and had a couple of these for a number of years.

I would recommend regularly changing the battery with new fresh batteries, and have new backup batteries, for two good reasons: 1) Obviously you don't want it to stop unexpectedly. 2) batteries leak after awhile. One of mine did and the small circuit board failed. It powered up and initially I felt the pulse O2 coming through the mask. I had just leveled off at FL023 and something didn't feel right plus the pulses weren't very often. I asked for lower and discovered that my o2d2 was operating intermittently. That flight turned out ok at a lower altitude. When I called Mountain High they said that the most common failure is battery leakage - that the batteries being made now don't hold up as well as batteries made a few years ago. I sent it in and had it refurbished and a new board installed. The documentation says not to use lithium batteries, which I never have, and to take the batteries out if you aren't using it for 30 days. Also MH says it needs to be sent back every few years to be recalibrated, collars and o-rings changed, etc.

Repair invoice on the battery leak damage: https://www.dropbox.com/scl/fi/i3f8wccg3pkgxyjrek021/O2D2-repair.pdf?rlkey=2smq77y2fhqymc1jfmb5lpuxt&dl=0

Regular service invoice on both units: https://www.dropbox.com/scl/fi/32p1mq4jrei78jgvh5tp1/O2D2-regular-service.pdf?rlkey=bffsd7zwinn3e3y2z2i5m15e5&dl=0

I still own one of these, but since 2017 though, if I'm flying lower than FL180 I use an Inogen G3 oxygen generator with a cannula.

**Marc_B** · June 9, 2024

16 hours ago, Boilermonkey said:

Buy yourself a system to refill yourself

It sounds like the OP may not even need to do this. With the oxysaver cannulas, he may be able to go to having refills at annual each year or maybe once in between annual. To me that doesn't justify the cost of a refilling cascade and one more thing to keep up with. @Max Clark Fly a year with the oxysaver and see what your use is first before loading up on gear.

edit: (for comparison, I can get a fill locally for $60; at annual they charge $80). POH says don't go below 100PSI. To give a little leeway, and to make sure I don't have a trip where I need O2 but don't have it, I start thinking about it by 500PSI and refill before 300PSI or if I have a big trip(s) coming up. This will keep you with a pilot only 3 hr oxygen flow at 18,000 ft. AFMS for oxygen system attached if you don't have it.

Oxygen_AFMS.pdf

**Marc_B** · June 9, 2024

41 minutes ago, LANCECASPER said:

I would recommend regularly changing the battery with new fresh batteries,

I've stopped using Duracell for this reason. I've had more leaks with Duracell then other main brands. Also I always replace batteries at annual regardless of their condition...figured it I do this for smoke alarms, why would I do less for my safety equipment that I use all the time.

52 minutes ago, LANCECASPER said:

The documentation says not to use lithium batteries, which I never have, and to take the batteries out if you aren't using it for 30 days.

I think that the recommendation for alkaline vs lithium has to do with the voltage sense of the O2D2. Lithium batteries maintain their voltage almost to the end of charge life, whereas the alkaline batteries reduce their voltage output throughout their performance. The O2D2 has a battery alert/monitor that I'm presuming is based on voltage sense which is likely calibrated to typical voltage drop curve of alkaline AA batteries. Surprisingly, my Bose A20 headset also says not to use lithium batteries...but the only thing on this end that I could find is that Bose mentions that a "fully charged lithium battery may overload headset."

image.png.e471bea04784f6ecfd62b90e77fa1220.png

**LANCECASPER** · June 9, 2024

5 minutes ago, Marc_B said:

I've stopped using Duracell for this reason. I've had more leaks with Duracell then other main brands. Also I always replace batteries at annual regardless of their condition...figured it I do this for smoke alarms, why would I do less for my safety equipment that I use all the time.

Excellent point! The Duracells that I had in there that leaked still had 8 years before the expiration date on the battery.

**exM20K** · June 9, 2024

1 hour ago, Marc_B said:

Also I always replace batteries at annual regardless of their condition...figured it I do this for smoke alarms, why would I do less for my safety equipment that I use all the time.

Same. Batteries are cheap, and a forced/scheduled change is almost foolproof.

Likewise, I run the TKS first flight of every month.

-dan

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