What was found
CLT - FLT 9215 - FERRY FLIGHT FROM MHT-CLT, EN ROUTE, WHILE AT FL390, THE AIRCRAFT EXPERIENCED A NR 1 CABIN PRESSURIZATION FAILURE, FOLLOWED TEN SECONDS LATER BY A NR 2 CABIN PRESSURIZATION FAILURE. A RAPID DESCENT WAS MADE TO 10,000 FEET. AFTERWARDS, THE FLIGHT CONTINUED TO CLT AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE REPLACED THE OUTFLOW VALVE. OK FOR SERVICE. (M)