Zirconia Oxygen Sensors for Aircraft Fuel Tank Safety and OBIGGS

Reducing Explosion Risk in Aircraft Fuel Tanks 

Aircraft fuel tank safety depends on preventing the conditions that allow fuel vapours to ignite. One effective approach is to reduce the oxygen concentration within the fuel tank vapour space below the level required to sustain a flammable atmosphere. 

By reducing the oxygen component of the fire triangle, an aircraft nitrogen generation system can significantly lower the risk of fuel vapour ignition. 

Fuel tank explosions in civil aviation are extremely rare, but aircraft manufacturers such as Boeing and Airbus continue to invest in advanced fire prevention technologies. Fuel system protection remains an important consideration throughout the design, testing, and certification of modern aircraft. 

Established Methods for Fuel Tank Inerting 

Fuel tank inerting has been used in military aviation for many years. Methods such as liquid nitrogen injection, halon systems, and reticulated foams have helped reduce fire risks in demanding operating environments. 

These approaches introduce an inert gas or otherwise reduce the oxygen available for combustion. The resulting atmosphere makes it more difficult for fuel vapours to ignite. 

Civil aircraft apply the same fundamental principle through On-Board Inert Gas Generation Systems, commonly known as OBIGGS. These systems generate nitrogen-enriched air and deliver it to the fuel tank to maintain safer atmospheric conditions. 

SST Zirconia Oxygen Sensors for OBIGGS 

Accurate and responsive oxygen measurement is essential to the reliable operation of an OBIGGS oxygen monitoring system. 

SST zirconium dioxide oxygen sensors are designed for demanding aerospace applications where measurement stability, durability, and fast response are critical. Each zirconia oxygen sensor provides the control system with the information required to verify oxygen concentration within the nitrogen-enriched air stream. 

SST oxygen sensors are integrated into OBIGGS control systems across a range of aircraft, including platforms manufactured by Boeing and Airbus. Their consistent measurement performance helps the inerting system maintain oxygen concentrations below the limits required for fuel vapours to remain flammable. 

How an On-Board Inert Gas Generation System Works 

The OBIGGS process begins with air supplied by the aircraft engine or bleed-air system. This air is conditioned to the required pressure and temperature before entering one or more Air Separation Modules. 

Inside each Air Separation Module, a porous membrane separates oxygen from the airflow. This process produces a nitrogen-enriched air stream, commonly referred to as NEA. 

The NEA is delivered into the aircraft fuel tank, where it forms a protective layer above the fuel surface. By displacing oxygen in the vapour space, the nitrogen-enriched air helps maintain conditions below the flammability threshold. 

SST oxygen sensors continuously monitor this process. Accurate NEA oxygen monitoring allows the OBIGGS control system to verify stable operation throughout the different phases of flight. 

Designed for Reliable Aerospace Oxygen Monitoring 

SST zirconium dioxide oxygen sensors are engineered for continuous operation in demanding aerospace environments. 

Their solid-state construction contains no consumable sensing elements and supports: 

• Fast response to changing oxygen concentrations 

• Stable long-term measurement 

• Operation across changing temperatures 

• Resistance to vibration 

• Reliable performance during pressure variations 

• Integration into modern aircraft fuel tank inerting systems 

These characteristics make SST oxygen sensors suitable for aircraft nitrogen generation systems where dependable measurements are essential to fuel system safety. 

Speak with an SST Sensing Expert 

Need technical guidance or an oxygen sensor recommendation for an OBIGGS or aircraft fuel system safety application? 

Call our team on +44 (0)1236 459020 or speak with an expert.