As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON CLIMB OUT F/O'S VSI WAS INDICATING 500 FT PER MINUTE. CAPTAIN'S VSI WAS INDICATING 1300 FT CLIMB PER MINUTE. CREW IN CONSULTING WITH MAINTENACE DETERMINED F/O'S VSI NOT FUNCTIONING. AIRCRAFT COMPLETED AIR TURN BACK. DURING TROUBLESHOOTING F/O'S VSI INDICATED RA FAIL, AND GIVING ERRATIC READINGS DURING TEST. F/O'S VSI REPLACED.