What was found
DURING CLIMB, DUCT USING RIGHT PACK ONLY, WERE UNABLE TO MAINTAIN PRESSURIZATION ABOVE FL 20,000. AIR TURN BACK TO BRUSSELS. REMOVED AND REPLACED PACK SWITCH. (M)
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
DURING CLIMB, DUCT USING RIGHT PACK ONLY, WERE UNABLE TO MAINTAIN PRESSURIZATION ABOVE FL 20,000. AIR TURN BACK TO BRUSSELS. REMOVED AND REPLACED PACK SWITCH. (M)