What was found
PIT-ERI - FLT 257 - AFTER TAKEOFF, THE LANDING GEAR DID NOT RETRACT WHEN SELECTED UP. THE LANDING GEAR WAS RECYCLED, BUT STILL DID NOT RETRACT. THE FLIGHT THEN RETURNED TO PIT AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE UPSTOP DAMPER. OPS CHECK OK. (M)