As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BUF - FL 1078 - FIRST OFFICERS HSI LOCKED UP ON NAV AFTER LIFTOFF. THE CDI COURSE KNOB WOULD NOT ROTATE CDI AND SEEMED TO BE FROZEN IN NAV SELECTION. FLIGHT DIVERTED TO BUF AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE REMOVED AND REPLACED THE VOR/ILS NAV SWITCH ON THE GLARESHIELD. OPERATIONAL CHECK GOOD. (M)