As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT PACK FAILED INFLIGHT. RIGHT PACK DEFERRED. PERFORMED EMERGENCY DESCENT PROCEDURE PER QRH. LEFT PACK HEAT EXCHANGER CHECK VALVE HINGE AND SPRING WORN. REMOVED AND REPLACED CHECK VALVE (FAN BYPASS) PER MM 21-52-07. LEFT PACK OPS OK. P/N: 350023000.