Honeywell

Honeywell Aerospace is a leading global provider of integrated avionics, wheels and brakes, engines, systems and service solutions for aircraft manufacturers, airlines, business and general aviation, military, space and airport operations.

Honeywell Aerospace in the UK produce and supply Air Management and Life Support Systems for civil and military aircraft. It has vast experience and capability in Life Support, from a background of traditional, high pressure, stored gaseous and liquid oxygen to today’s On Board Oxygen Generation Systems (OBOGS). The consolidation of experience on the B-1B, B-2, F-22 and Eurofighter aircraft, and other state-of-the-art systems made it capable of being readily tailored to many different single/twin seat and multicrew aircraft and, ultimately, selection for the F-35.

Developed in the 1980’s at it’s facility in Yeovil, Somerset, Honeywell’s OBOGS technology allows an aircraft to generate its own oxygen from a conditioned air supply during flight, giving significant advantages in reliability, safety and performance over older gaseous and liquid oxygen systems. OBOGS takes advantage of a molecular sieve material, Zeolite, which traps nitrogen molecules when air is passed through it, allowing it to act as a molecular sieve.

At ground level humans breathe air with a 21% oxygen concentration in order to oxygenate the bloodstream and, hence, sustain life. The pressure exerted by the oxygen component of air is termed the Partial Pressure of Oxygen (PPO2). It becomes progressively more difficult for humans to take in oxygen as PPO2 decreases in direct proportion to air pressure with increasing altitude. At higher altitudes this will lead to insufficient oxygen being present in the bloodstream, a condition known as hypoxia, and eventually death. The OBOGS is controlled by a solid state monitor/controller that monitors the PPO2 level of the OBOGS product gas, and adjusts the cycling of the beds to produce the desired level of oxygen concentration. To prevent hypoxia in military aircrew it is necessary, as a rule of thumb, to maintain the minimum of PPO2 to the equivalent of altitudes in the range 8,000 feet to 10,000 feet in order to perform normal levels of work.