As a participant in the three-nation partnership for development of the ANBCP-S for use in Helicopters, Transport Aircraft and Fast Jet, the Royal Netherlands Airforce (RNLAF) picked up the challenge to design a Filter- Blower-Unit (FBU). Major Command (MajCom) of the RNLAF set priority to develop a system for Helicopter use first. After that the same system is to be used in Transport Aircraft and Fast Jet. The FBU is supposed to provide clean air for breathing, body and head cooling and demist of the vision system. Because of special knowledge required to set specifications for this FBU, the RNLAF contracted a Dutch Research Institute, TNO. TNO has the capability to do all research and testing to set all requirements. The RNLAF asked TNO to quantify the amount of air needed for breathing, body and head cooling and demist of the vision system. Some of the basic requirements set by MajCom are: - The system must be Man mounted, - Battery powered; - Filtersytem must be based on the NATO canister system; - It has to operate continues, without major changes, for a period of eight hours. Several trails were performed to quantify the acquired amount of air in terms of oxygen consumption, ventilation and corresponding cooling rates. During those trails it became clear there is a big difference in consumption between a Pilot and a Loadmaster. Therefore our primary goal is to develop a system which is suitable for the most difficult crewmember to equip. To the opinion of TNO and RNLAF that is the Loadmaster. TNO performed trails in house and on location. On location they used the equipment of Soesterberg (SSB) Airforce Base (AFB) (The Netherlands) and flightsimulators in Marseille (France) (AS532U2) en Benson (United Kingdom) (CH47D). Simultaneous the RNLAF performed some integration test to find out the maximum volume of the configuration of the FBU with power source. As well the maximum amount of Filter canisters which can be carried by a crewmember.