As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKEOFF, CREW HAD TROUBLES WITH LANDING GEAR, MAIN GEARS WOULD NOT RETRACT. NOSE RETRACTED NORMALLY. ALTERNATE LANDING GEAR EXTENSION ACC. CHECKLIST DONE. UNEVENTFUL LANDING. AIRCRAFT HANDED OVER TO MAINTENANCE. NO FAULTS CODES. FOUND BYPASS VALVE FILTER COLLAPSED, FILTER REPLACED, A/C RTS. (TC NR 20071002006)