What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Narrative: while in cruise flight at 37,000 ft., cabin began to climb at 2000 ft/min. Pilots noted that l. duct pressure was 42 PSI on l. engine EGT was 754 degrees, right duct pressure was 12 PSI and r. engine EGT was 663 degrees. Attempts to control pressurization failed. The left air pack tripped off. A loud rush of air was heard and the cabin began to climb at 4000 + feet/min. An emergency was declared. An emergency descent initiated. Pilot deployed the cabin oxygen masks. At aircraft altitude 28,000 ft., the cabin altitude was stable and did not exceed 10,000 feet. A maintenance investigation defective prsov, and precooler valve on right side both items were replaced. Right safety valve was found damaged and replaced. Left turbine overheat sensor, left compressor discharge switch, left mix valve, left pack actuator replaced. Left 250 degree sensor and 190 degree sensor replaced. Pressurization system checked and found satisfactory. Submission of this report closes this incident.
As the FAA filed it
NARRATIVE: WHILE IN CRUISE FLIGHT AT 37,000 FT., CABIN BEGAN TO CLIMB AT 2000 FT/MIN. PILOTS NOTED THAT L. DUCT PRESSURE WAS 42 PSI ON L. ENGINE EGT WAS 754 DEGREES, RIGHT DUCT PRESSURE WAS 12 PSI AND R. ENGINE EGT WAS 663 DEGREES. ATTEMPTS TO CONTROL PRESSURIZATION FAILED. THE LEFT AIR PACK TRIPPED OFF. A LOUD RUSH OF AIR WAS HEARD AND THE CABIN BEGAN TO CLIMB AT 4000 + FEET/MIN. AN EMERGENCY WAS DECLARED. AN EMERGENCY DESCENT INITIATED. PILOT DEPLOYED THE CABIN OXYGEN MASKS. AT AIRCRAFT ALTITUDE 28,000 FT., THE CABIN ALTITUDE WAS STABLE AND DID NOT EXCEED 10,000 FEET. A MAINTENANCE INVESTIGATION DEFECTIVE PRSOV, AND PRECOOLER VALVE ON RIGHT SIDE BOTH ITEMS WERE REPLACED. RIGHT SAFETY VALVE WAS FOUND DAMAGED AND REPLACED. LEFT TURBINE OVERHEAT SENSOR, LEFT COMPRESSOR DISCHARGE SWITCH, LEFT MIX VALVE, LEFT PACK ACTUATOR REPLACED. LEFT 250 DEGREE SENSOR AND 190 DEGREE SENSOR REPLACED. PRESSURIZATION SYSTEM CHECKED AND FOUND SATISFACTORY. SUBMISSION OF THIS REPORT CLOSES THIS INCIDENT.