Flight test of a pressurization system used to measure minor atmospheric constituents from an aircraft

A flight evaluation of an ambient air sample pressurization system was conducted at altitudes between 6 and 12 km. The system regulated the sample pressure to 10.15 + or - 0.1 N/sq n and provided sample flow to three gas analysis instruments included in the system. Ozone concentrations measured by two instruments employing different techniques varied from about 30 parts per billion by volume (ppbv) to over 350 ppbv, and the two ozone monitors agreed to within 20 ppbv. A carbon dioxide analyzer indicated modifications required for future installations.