By Mountain High Staff

In aviation, supplemental oxygen is a crucial safety require­ment for pilots and passengers flying at high altitudes, as well as a great way to avoid feeling tired and sluggish after a flight.

Getting an Oxygen Cylinder Filled Can Be Difficult and Expensive

Not all FBOs are equipped for refilling oxygen and others may not have the correct adapters to connect to your bottle or built-in system. Further, prices vary dramatically from one loca­tion to another and can cost $150 or more, as is often the case if you are billed for a full hour at an hourly shop rate.

Fill Your Own Oxygen Cylinder

For aircraft based at private hangars, it can be more efficient and cost-effective to maintain one or more large oxygen supply tanks on-site. This guide explains how to order a bulk oxygen supply tank, get it delivered to a private hangar, and use it to refill portable oxygen cylinders.

Step 1: Determine Your Oxygen Needs

Before ordering a supply tank, assess the following:

1. Type of oxygen required: Aviator’s Breathing Oxygen (ABO) is the standard for aviation.

1. Volume and usage frequency: Consider how often you use your portable cylinders and how many aircraft will draw from the supply. This helps determine the appropriate tank size (measured in cubic feet). It is also possible to cascade multiple supply tanks together for more efficient refilling.
2. Storage: Ensure your hangar has sufficient space and proper ventilation for storing a high-pressure oxygen cylinder safely, away from direct sunlight, heat sources, and flammable materials.

Step 2: Choose a Vendor

Several reputable suppliers specialize in aviation-grade oxy­gen. Here are a few options to consider:

1. Airgas: www.airgas.com
2. Praxair (now Linde): www.lindeus.com
3. A Local Oxygen Supplier: Consider a quick internet search for ABO oxygen suppliers in your area.

Safety Precautions:

• No smoking or open flames.
• Use oxygen-rated lubricants only (never use petroleum-based products).
• Always open valves slowly and monitor gauges closely.

Step 5: Refilling Portable Oxygen Cylinders

Here’s how to safely refill a portable cylinder from your supply tank:

1. Check the portable cylinder: Inspect for damage, ensure it’s clean, and confirm it’s rated for refill (some disposable ones are not).
2. Connect: Attach the transfill hose to both the main supply and the portable cylinder using compatible CGA-540 fittings.
3. Equalize slowly: Open the supply tank valve slightly to begin the flow. Watch the pressure gauge on the destination tank to ensure a slow, controlled fill—rapid fill­ing can cause heating and stress the cylin­der. Also, because a heated cylinder loses pressure as it cools, heating the cylinder during transfilling ultimately yields less available oxygen in flight.
4. Stop at target pressure: Usually 1800– 2200 PSI for portable cylinders. Do not overfill.
5. Shut off and bleed: Close all valves, then bleed the hose to depressurize before dis­connecting.

Resources: Transfilling Videos

Mountain High has produced a series of videos which cover the entire process of transfilling, including safety tips, how to identify and purchase needed supplies, and step-by-step instructions.

Website: www.mhoxygen.com > Videos > Transfilling

Start with How to Fill Your Own Oxygen Cylinder.

Final Considerations

• Maintenance and inspections: Both portable tanks and supply tanks must be hydrostatically tested periodically (typically every 5 years). Regulators and hoses should be inspected regularly for leaks or wear.
• You can also fill a built-in oxygen system: With the right adapters to connect a supply cylinder to the fill port on your plane, you can use the same process described in this article to fill your built-in oxygen system. Mountain High can help you identify the adapters you’ll need. You might also watch Using Transfill Adapters on www.mhoxygen.com.
• Cascading multiple supply tanks: You can reduce the number of supply cylinder exchanges by cascading (i.e. daisy chaining) multiple supply cylinders together. This enables you to preserve high-end pressure in some tanks while utilizing otherwise discarded low-end pressure in others. Learn more in Mountain High’s How to Cascade Oxygen Supply Tanks video.

Conclusion

Keeping an oxygen supply tank at your private hangar makes it easy and affordable to fill your own cylinders. Ordering a tank is straightforward, and with just a few simple steps, you’ll be fill­ing your cylinders quickly and confidently. Having a full oxygen supply on hand means you’re always ready to fly higher, reduce the risk of hypoxia, and arrive at your destination feeling clear-headed and refreshed — on every flight.

Mountain High has been a leading provider of aviation oxygen systems to the general aviation community since 1985. Dedicated to enhancing pilot safety, comfort, and performance at altitude, Mountain High focuses on innovative engineering, maintaining the highest quality, and providing customer service which is second to none. mhoxygen.com