Hydrostatic Test Frequencies for Aviation Gas Cylinders

05 Jan Hydrostatic Test Frequencies for Aviation Gas Cylinders

CASA Regulations

The Civil Aviation Safety Authority (CASA), in accordance with AD/GAS/1/ & AS 2030, requires that all aircraft compressed gas cylinders undergo periodic hydrostatic testing to verify their structural integrity under high-pressure conditions and to ensure they remain free of stress fractures, corrosion, or pitting.

Under Australian standards, different cylinder specifications dictate specific retest intervals and total service life limits:

• Steel Cylinders (e.g., 3AA Equivalent): These must be hydrostatically tested every five years and generally have an indefinite service life, provided they continue to pass inspection.
• High-Strength Steel Cylinders (e.g., 3HT Equivalent): These require testing every three years and are subject to a maximum service life of 24 years from the date of manufacture.
• Composite Cylinders: These lightweight cylinders must be tested every five years and normally carry a maximum service life of 15 years; after which they must be retired from service. The end-of-life date can vary upon the gas cylinder OEM.
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CASA requires that all aircraft oxygen cylinders be hydrostatically tested regularly to verify that they can operate under high-pressure circumstances and are free of stress fractures and rust. Different types of oxygen cylinders require varying testing durations and service life criteria:

Australian Standards

AS2030.5 Cylinders forming part of an Aircraft equipment and used solely in aircraft, other than a reference made in a direction pursuant to the Civil Aviation Regulations. 

Gas Cylinders, which are part of aircraft fixed systems, or Gas Cylinders holding a water capacity under 0.1kg or greater than 3000kg, do not fall under Australian Standards AS2030; reference needs to be made back to the Aircraft “CMM” Component Maintenance Manual specified by the Aircraft’s OEM. 

AS2030.6 Initial test station inspection and testing 

Gas Cylinders, which are required to be filled for the first time within the Commonwealth of Australia, are required to go through an approved gas cylinder test station, be inspected, tested, and certified then have a test station mark stamped onto the gas cylinder.         

Gas Refills

All Aviation Gas Cylinders should not undergo gas refills if the test dates have expired, or portable gas cylinders do not bear an Australian Gas Cylinder test mark.
Please note that this only applies to aircraft solely used in the Commonwealth of Australia.

Before initial filling, all new carry-on use cylinders must be tested and display a valid Australian Gas Cylinder Test Stamp.

Before refilling, older cylinders must be checked to ensure they remain within their approved test period by verifying the Gas Cylinder Test Stamp and its associated dates.

Example of an Australian Gas Cylinder Test Stamp and dates (depicting the bottle as having been tested in February 2026).

Before initial filling, all new carry-on use cylinders must be tested and display a valid Australian Gas Cylinder Test Stamp.

Neglecting this procedure can pose risks to both the operator and the refiller, exposing them to potential injury and legal consequences in the event of an incident.

It is important to note that gas bottles integrated into the fixed systems of an aircraft are exempt from the regulations specified in AS2030 and AS2337.

Consequently, no Australian test stamp or initial hydrotest is required prior to the first filling according to these standards.

If you have any questions, please do not hesitate to reach out to us today.

Portable Carry-On Bottles

Portable (Carry-On) Oxygen Bottles – Pilot Use

New portable gas bottles intended for carry-on use, and not connected to the aircraft’s fixed systems, must comply with AS2030 and AS2337 standards under the Gas Cylinder Test Scheme.

New bottles released into service must undergo a hydrostatic test and be stamped with the gas cylinder test stamp and the month and year of the test before the first fill.

They must then be retested according to their designated test cycles.

These are typically classified as:

    •    Portable safety/survival equipment

    •    Loose equipment or carry-on operational equipment

    •    Not part of the aircraft’s certified oxygen system

Aircraft Fixed Systems Gas Cylinders

Gas bottles designed for integration into the aircraft’s fixed system are not subject to AS2030 and AS2337; however, they must be retested when their scheduled retest date is due.

New gas bottles released into service must undergo a hydrostatic test and be stamped with the gas cylinder test stamp, along with the month and year of the test, before the first fill.

They must then be retested according to their designated test cycles.

Aluminium, Composite, Steel Gas Cylinders

Composite, Steel, Aluminium Aircraft Gas Cylinders
Require retesting in accordance with AS2030 & AS2337, DOT Requirements. 

For Composite Gas Cylinders, Attention to detail is required to verify the end-of-life dates on the cylinder.

For Aviation Cylinder Retesting, Inspections, And End-Of-Life Support

Need to know more about Aviation Bottle Testing, Click Here.

If your aviation composite gas cylinder is due for retest, inspection, or you need help determining its end-of-life status, contact Fire System Services. 1300 88 3473
 info@firesys.com.au

Fire System Services are aviation-certified and ready to assist.