What was found
MAY 19. CKPT OXY F/O SIDE POSSIBLE AIR LEAK, IN FLIGHT IT DROPPED FROM 640 PSI TO 540 PSI ,IT DROPS 10 PSI EVERY 15 MINUTES APROX // CORRECTIVE ACTIONS: MAY 20. IN ACCORDANCE WITH AMM 35-11-41 PB 401 CONF 01, COCKPIT OXYGEN CYLINDER F/O SIDE WAS REMOVED AND REPLACED. LEAK TEST WAS SATISFACTORY.