As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AT FL 350 #1 PACK FLOW VALVE FLUCTUATED BETWEEN LOW AT 50 O/O CAUSING CABIN TO CLIMB 100FT PER MIN AND DECLINE 150 FT PER MIN CONTINUALLY. AT THE BEGINNING OF DECENT CABIN VERT SPEED FLUCTUATED BETWEEN 100 AND 150 FT. **SUPPLEMENTAL REPORT WILL BE SUBMITTED** (OPEN)