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OBIGGS for helicopter

A reliable and autonomous inerting system to protect the helicopter fuel tanks against fire or explosion

The On-Board Inert Gas Generating System (OBIGGS) produces the flow of Nitrogen Enriched Air (NEA), keeping the ullage non-flammable. Due to its compact design and well-proven equipment, the OBIGGS for helicopters is a reliable solution in a small form factor. By reducing the proportion of oxygen, it fully prevents the fuel tanks against any risk of fire or explosion.


  • Air Liquide proprietary technology for hollow fibers in the ASM (Air Separation Module)
  • Compact lightweight system, tailored for helicopter design - Flexible and simple integration
  • Fast and accurate regulation of the gas
  • No calibration nor logistic
  • Reduced schedule maintenance
  • Full Air Liquide support for OBIGGS integration and gas distribution design

How does it works

Based on a hollow fiber separation process, the OBIGGS allows to produce during the mission the flow of Nitrogen Enriched Air (NEA) requested to protect the helicopter. Part of the oxygen contained in the fuel tank is replaced by Nitrogen, thus reducing the proportion of oxygen and therefore keeping the vapors non-flammable.

The OBIGGS includes a Temperature Control System, a filter, a pressure controller, an oxygen sensor and an Air Separation Module (ASM). Hence, compressed air is directly tapped on Helicopter engine air and transformed into NEA that can be directly distributed in the fuel tanks. Air Liquide designs and manufactures its own hollow fiber used inside the ASM. Its performance allows a particularly compact design. Consequently, the Air Liquide OBIGGS can be easily installed on the Helicopter. 

Besides, Air Liquide supports the customer to design the distribution system, from the fiber to the system: Inerting modeling, piping sizing, supply of distribution components. The use of the OBIGGS does not need any calibration or logistic operation before the flight. By means of the control of a selected set of signals generated by the OBIGGS, the crew is permanently aware of the status of the equipment.

Performance and technical specifications

  • Separation by Air Liquide hollow fibers membrane
  • Temperature Management System (TMS) allowing to use bleed air with temperatures up to 400°C
  • Integrated controller including a pressure regulator, a shut-off valve, a flow regulator and an oxygen analyser
  • Control signals to be aware permanently of the operational status of the equipment

Light helicopter

Large helicopter


< 4.5 kg

< 12 kg


0.15 lb/min

0.4 lb/min

NEA quality

up to 4 % O2

up to 7 % O2

Power supply

28 Vdc - 115 Vac  / 400 Hz

28 Vdc - 115 Vac / 400 Hz

Example of typical performance. Solution is tailored to each helicopter model.


  • Qualified according to MIL-STD standards

Discover also

Oxygen analyzer

As part of an OBIGGS, the oxygen analyzer ensures that the system is in good working order. It analyzes the oxygen-depleted gas and sends an electrical signal reflecting the quantity of oxygen as a percentage or in partial pressure. The O2 analyzer is fitted with a zirconium oxide sensor to ensure its precision and reliability. It can operate at a wide range of pressures, from a few millibars to several bars and temperatures of up to 300°C.

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Air Liquide designs, manufactures and services gas-related equipment on board aircraft and on the ground, for civil and military markets.

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