What was found
CLIMBING THROUGH APPX FL200, RECEIVED CABIN ALTITUDE CAUTION THEN WARNING. PACK 1 WAS ALREADY MEL'D. FLYIN ON PACK 2 ONLY. MAX CABIN ALTITUDE OBSERVED AROUND 10,700 AND CLIMBING. CREW DONNED 02 MASKS AND PERFORMED EMERGENCY DESCENT TO SAFE ALTITUDE OF 11,000MSL. AT THIS LOWER ALTITUDE, CABIN DID HAVE SOME PRESSURING CAPABILITY AND RETURNED TO GREEN NORMAL RANGE. DIVERTED AND PERFORMED NORMAL WEIGHT LANDING. ALL PRESS INDICATIONS ON GROUND NORMAL. EMERGENCY DECLARED. OPS CHECKED PACK 1 AND PACK 2 PER AMM 21-51-00, PERFORMED CABIN PRESSURIZATION CHECK PER AMM 21-31-00. OPS CHECK GOOD.