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OBIGGS for aircraft

A reliable and autonomous inerting system to protect the aircraft 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 simple design and well-proven equipment, the OBIGGS is a reliable solution to fully prevent the aircraft tanks against any risk of fire or explosion by reducing the proportion of oxygen.


  • Air Liquide proprietary technology for hollow fibers in the ASM (Air Separation Module)
  • Compact lightweight system - Flexible and simple integration
  • Temperature Management System allowing to use bleed air with temperatures up to 400°C
  • 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 molecular separation process, the OBIGGS allows to produce during the mission the flow of Nitrogen Enriched Air (NEA) requested to protect the aircraft. Part of the oxygen contained in the fuel tank is replaced by Nitrogen, keeping the vapors non-flammable.

The OBIGGS includes a filtration chain, a pressure & temperature controller, an oxygen sensor and air separation modules. Depending on the applications, it can integrate a Temperature Management System to condition the bleed air. Compressed air is directly tapped into an aircraft air circuit and transformed into NEA that is directly distributed in the fuel tanks.  

20-years experience in fuel tanks explosion reduction enables Air Liquide to support the customer also for the design the distribution system: Inerting modeling, piping sizing, NEA injection location, 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 “MEDAL” hollow fibers membrane
  • 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

Cargo aircraft

Trainer or Fighter aircraft


< 35 kg

< 10 kg

débit NEA Flow

Up to 2 lb/min

Up to 0,2 lb/min

NEA Quality

Up to 1 % O2

Up to 4 % O2

Power Supply

28 Vdc

28 Vdc

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


  • Qualified according to MIL-STD standards 
  • RTCA DO-160

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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