Do you have oxygen onboard? Aircraft designed for higher-altitude flight often are pressurized and/or come with a built-in oxygen system. Pilots of lower-altitude, unpressurized aircraft, on the other hand, need to put together a portable supplemental oxygen system.

The FAA requires pilots to use oxygen when flying above 14,000 feet or when spending more than thirty minutes at or above 12,500 feet. That’s not the end of the story though.

Even though it’s not required, the FAA recommends pilots use oxygen above 6,000 feet at night and above 10,000 feet during the day.

Based on those recommendations, we should all have supplemental oxygen onboard and use it for many of our flights.

If you haven’t yet outfitted your plane with oxygen or you’re due for an upgrade, stick around. In this guide we will dive into everything you need to know about your aviation supplemental oxygen options and how to choose the configuration and gear that’s best for you.

A portable Oxygen Tank and Mask

What oxygen equipment do I need to fly?

No matter what type of pilot oxygen system you pick, you need the following pieces of equipment:

    • Tank(s) of compressed oxygen
    • Regulator
    • Oxygen delivery device(s)

We also recommend:

    • An SpO2 meter, also known as a pulse oximeter, to measure your blood oxygen levels
    • A flowmeter (depending on your system)

How Portable Oxygen for Pilots Works

Portable oxygen comes in highly pressurized cylinders. Our lungs can’t handle the 2000 PSI pressure of personal oxygen tanks. Before we can use the oxygen, the pressure must be reduced to a breathable level using a regulator.

After the oxygen pressure is decreased by the regulator, the oxygen flows through tubing, and into our oxygen delivery device.

When we breathe in supplemental oxygen, the increased oxygen concentration helps compensate for the decreased atmospheric pressure, so the cells of our bodies keep getting the oxygen they need even as we climb to higher altitudes.

Oxygen System Types

There are several types of on-board oxygen for pilots. Each is designed for use within a specific altitude range. Some systems are built in while others are portable.

The three main types of oxygen system designs and their use altitude ranges are:

    • Continuous flow: up to 25,000 feet
    • Diluter demand: up to 40,000 feet
    • Pressure demand: above 40,000 feet

Continuous Flow Oxygen Systems

Continuous flow designs are the simplest, least expensive type of supplemental oxygen system for pilots. Most general aviation pilots will use a continuous flow system since it is portable and works at pressure altitudes of up to 25,000 feet.

You have three flow rate options with a continuous flow system.

Set Flow Rate

The most basic continuous flow configuration uses a constant flow oxygen regulator. With a constant flow regulator, once the tank is turned on, oxygen flows freely and is continuously released whether you are breathing it or not.

The oxygen is always flowing at the same rate through the canula or mask regardless of altitude and your body’s needs. A potential downside of this setup is that the constant flow can mean wasted oxygen at lower altitudes and not enough oxygen at higher altitudes.

Adjustable Flow Rate

An altitude adjustable continuous flow regulator uses an inline flowmeter to let you change your oxygen flow rate depending on altitude. The oxygen is still always flowing, but you can decrease the rate at lower altitudes and increase it at higher altitudes to conserve oxygen.

Altitude Compensating Flow Rate

Altitude compensating continuous flow systems are usually only an option for built-in systems, not portable. With a compensating system, instead of you needing to manually adjust the flow rate based on altitude, the system automatically does it for you.

Diluter Demand Flow Systems

A diluter demand system is more attuned to the respiration pattern of the person using it. When the system senses you breathing in, a conserving regulator supplies oxygen. The oxygen flow stops during exhalation and in between breaths. This eliminates wasted oxygen being pumped out of the tank and can reduce oxygen use by 50-85%.

Another oxygen conservation trait of the diluter demand system is that the oxygen from the tank is combined with cabin air before you breathe it in. An auto-mix level uses barometric pressure data to deliver the optimal oxygen percentage with each respiration.

Rather than breathing 100% oxygen, you get the standard 21% oxygen level your body is used to, and you keep more oxygen in your tank in the process. Diluter demand systems are typically used from pressure altitudes of 25,000 to 40,000 feet.

There is no waste with a conserving regulator, but the user must remember to breathe deeply enough to trigger the regulator to release oxygen.

Quick Tip

Pro Tip: Since the system must be able to sense inhalation, diluter demand masks are tightly fitted to the nose and face. Pilots and passengers with claustrophobia may need time to get used to wearing the mask.

Pressure Demand Flow Systems

A pressure demand oxygen system is used at high altitudes (think Top Gun fighter pilots) not only to provide oxygen flow, but also to create forced pressure behind that flow.

The pressure is needed to push the oxygen into the pilot’s lungs at altitudes where the ambient pressure is very low. This pressurization technique allows pilots to fly at altitudes over FL400 where the air is so “thin” that pilots would become hypoxic even breathing 100% oxygen without pressurization.

Close up of an oxygen mask with tubingOxygen delivery devices

The altitude you are flying at will determine not only what type of oxygen system you use, but also the delivery device you pair with it.

Here’s the breakdown of what to wear at each altitude:

    • Nasal cannula: Under 18,000 feet (FL180)
    • Re-breather mask: Up to 25,000 feet (FL250)
    • Diluter demand mask: Up to 40,000 feet (FL400)
    • Pressure demand mask: Over 40,000 feet

Nasal cannula vs rebreather mask for pilots

We already talked about the diluter demand and pressure demand masks, but let’s compare cannulas and rebreathers. Both can be paired with a continuous flow system and worn below 18,000 feet where most general aviation pilots will be flying.

Pros and cons of a nasal cannula

Below 18,000 feet, most pilots use nasal cannulas since they are less cumbersome and can easily be worn while eating, talking to passengers, and using the radio.

When wearing a cannula, it is important to remember to breathe through your nose not your mouth, or you won’t take in as much oxygen. Cannulas can also waste more oxygen compared to rebreather masks.

Pros and cons of a rebreather oxygen mask

Masks are more effective than cannulas for pilots who often breathe through their mouths. The mask fits over the nose and mouth so you are receiving oxygen no matter how you breathe. With a re-breather mask and constant flow regulator, oxygen flows into a reservoir bag and you simply breathe normally.

Basic constant flow masks can get in the way during radio communication, but more advanced masks have built-in radio and intercom microphones to fix this problem.

Quick Tip

Pro Tip: Beards and mustaches can get in the way of rebreather oxygen masks. Do a fit test on the ground and confirm you’re getting a good seal. You may need a quick pre-flight trim.

How to Choose a Portable Oxygen System

The best portable oxygen systems are the ones you will use. Don’t choose a system that is so bulky, hard to use, or uncomfortable that you dread and avoid using it. Pick what will work for you by walking through the steps below.

1.      Select a system type

Your system type is dictated by the maximum altitude you will be flying at. Since most GA pilots stay below 25,000 feet, a continuous flow system is the correct choice.

2.      Select an oxygen delivery device type

When flying below 25,000 feet, you can choose either a cannula or a rebreather mask.

If you like the idea of a cannula but are concerned about wasted oxygen, hold that thought and keep reading. We have a solution for you in the next section.

Quick Tip

Pro Tip: When ordering your cannulas or masks, remember to plan not only for you but also for anyone who may fly with you. It’s also a good idea to keep extra delivery devices onboard as spares in case of a malfunction.

3.      Select a regulator type

To choose the best regulator for your needs consider the following variables:

  • Type of oxygen delivery device(s) you’re using it with (cannula or mask)
  • Number of simultaneous users (single person or multiple)

4.      Calculate your tank size

We will get into oxygen tank size calculation details a little later. For now, just know that you need to do a little bit of (easy) pilot math to pick the right tank for your altitude, flight duration, and the number of people using the oxygen.

5.      Add a flowmeter (optional)

Remember, your continuous flow system can use an inline flowmeter that gives you the ability to manually adjust the flow rate as you please. Add this to your shopping cart if it doesn’t come with your system.

6.      Add a pulse oximeter (strongly encouraged)

The FAA doesn’t require it, but remember that a pulse oximeter, or SP02 meter is one of the very best and easiest ways to stay on top of how much oxygen your body is absorbing throughout your flight.

Oxygen Tank

Aerox: The Best Aviation Oxygen System for General Aviation Pilots

Now that you know what to look for, there are a few different portable pilot oxygen systems to choose from. If you ask for our favorite, we’d pick Aerox, and here’s why:

Complete system packages and individual components

With Aerox, you can opt for a pre-packaged full system kit or piece one together yourself. You can also add individual components like extra cannulas or masks to an existing kit.

In May 2022, Aerox acquired Sky-Ox, another large aviation oxygen system supplier. This added to the already impressive range of products offered by the company.

Proprietary oxygen conserving nasal cannula design

One of the biggest beefs pilots have with traditional continuous flow nasal cannulas is how they waste oxygen by allowing the excess to escape.

Aerox has fixed that problem by designing an ultra-efficient Oxysaver cannula that works much like a rebreather mask. A small reservoir captures exhaled air and mixes it with the correct amount of oxygen to meet your needs.

Paired with a low-flow meter, the upgraded Aerox cannula can increase your oxygen tank life by up to 8 times that of a basic continuous flow system.

It has also been designed with headset use in mind. The Oxysaver can be worn comfortably with your favorite headset and it won’t get in the way of your boom mic.

Flowmeter and flow valve that work with both cannulas and masks

Aerox doesn’t make you choose between using a cannula or mask. Their flowmeter indicator has dual oxygen flow and altitude scales for use with either cannulas or masks.

The metal adjustable flow valve also lets you adjust oxygen flow for your delivery equipment type, with settings for standard cannulas, Oxysaver cannulas, and masks.

Multi-place system configurations

The Aerox oxygen system comes in one, two, and four-place configurations so you can choose the setup you need for just you or your entire family.

 Aerox Oxygen Systems

Aerox Oxygen Systems

Go longer between oxygen refills with the lightweight, durable, all-metal Aerox oxygen system that allows you to fly at higher, more fuel-efficient altitudes and summit hazardous weather for smoother, safer ops. The rugged units will easily work with any aircraft and come with all the components you need for one-handed, maintenance-free operation.

View Product

How long does a portable oxygen tank last?

When explaining how to choose your portable oxygen system, we mentioned tank size calculation. Here are some more details on how to pick your tank.

The amount of time your oxygen tank lasts depends on these factors:

    • Size of tank
    • Number of users
    • Altitude
    • Type of regulator
    • Type of delivery system (cannula vs mask)

Aerox Oxygen Systems provides aviator’s breathing oxygen in A, C, D, M, and E sized cylinders. The A-sized cylinders are the smallest tank, holding 6 CF (cubic feet) of compressed oxygen. The C-cylinders hold 9 CF, the D-cylinders hold 15 CF, the M-cylinders hold 22 CF, and the largest E-sized oxygen cylinders hold 24 CF of oxygen.

An oxygen cylinder size chart shows how many hours each size oxygen bottle can be expected to last at varying altitudes and with different numbers of users. 

Here is a breakdown of roughly how long you can expect each cylinder of Aerox portable oxygen to last (depending on your regulator and delivery system type):

  • A 1A oxygen cylinder with one user lasts an average of:
    • 12 hours at 10,000 feet
    • 7 hours at 15,000 feet
    • 6 hours at 18,000 feet
  • A 1C oxygen cylinder with one user lasts an average of:
    • 16 hours at 10,000 feet
    • 9 hours at 15,000 feet
    • 2 hours at 18,000 feet
  • A 1D oxygen cylinder with one user lasts an average of:
    • 7 hours at 10,000 feet
    • 8 hours at 15,000 feet
    • 3 hours at 18,000 feet
  • A 2A oxygen cylinder with two users lasts an average of:
    • 6 hours at 10,000 feet
    • 3 hours at 15,000 feet
    • 3 hours at 18,000 feet
  • A 2C oxygen cylinder with two users lasts an average of:
    • 8 hours at 10,000 feet
    • 4 hours at 15,000 feet
    • 1 hours at 18,000 feet
  • A 2D oxygen cylinder with two users lasts an average of:
    • 3 hours at 10,000 feet
    • 4 hours at 15,000 feet
    • 1 hours at 18,000 feet
  • A 2E oxygen cylinder or 2M oxygen cylinder with two users lasts an average of:
    • 3 hours at 10,000 feet
    • 0 hours at 15,000 feet
    • 0 hours at 18,000 feet
  • A 4D oxygen cylinder with four users lasts an average of:
    • 7 hours at 10,000 feet
    • 7 hours at 15,000 feet
    • 6 hours at 18,000 feet
  • A 4E oxygen cylinder or 4M oxygen cylinder with four users lasts an average of:
    • 7 hours at 10,000 feet
    • 5 hours at 15,000 feet
    • 5 hours at 18,000 feet

How to Use Oxygen in the Cockpit

Once you purchase your system, flying on supplemental oxygen is relatively simple. First, at a very minimum, follow the FAA regulations for supplemental oxygen use. Next, learn your own personal thresholds by monitoring your blood oxygenation with an SP02 meter. Apply oxygen at or slightly below the pressure altitude where you first start to experience mild hypoxia symptoms (if that altitude is lower than FAA minimums, which it most likely will be).

Include your oxygen system in your pre-flight checklist, and store the tank and delivery devices in such a way that you can reach them easily mid-flight.

Pre-flight checklist for oxygen equipment

In their oxygen equipment GA safety brochure, the FAA uses the acronym PRICE to remind pilots of the five parts of the oxygen equipment pre-flight check.

    • Make sure your tank has enough pressure to last the duration of the flight.
    • Inspect the regulator for proper function.
    • Check the flow indicator on the regulator or oxygen delivery tube. Put on a mask or cannula and confirm the flow indicator is showing a steady flow of oxygen.
    • Confirm all oxygen lines, plug-in coupling, and other system connections are secure.
    • Have emergency oxygen supplies on board. Ensure passengers know where to find them and how to use them. Review planned oxygen use with passengers.

More Pilot Oxygen Related Reads:

It’s Your Turn

We’re curious to hear from you. What does your oxygen system set up look like? Do you prefer a cannula or mask? Have you tried out the Oxysaver cannulas from Aerox? How did your oxygen tank life with the Oxysaver compare to regular cannulas?

Did you find this article helpful?

Do you think we missed anything important? Let us know in the comments below!


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