Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
ATC Issue All Types; Inflight Event / Encounter Other / Unknown
General None Reported / Taken
ATC Equipment / Nav Facility / Buildings
Second time in 2 nights we have had to execute the [SBY] ILS 32 approach. The first night the Captain performed the approach and commented on how the localizer was deviating quite a bit left and right of course within the final approach segment. I noticed the needle deflecting approximately a half dot left and right continuously to touchdown. I thought maybe it was bad reception on that aircraft itself until tonight. With a different aircraft we were executing the ILS and I was flying. I had the autopilot on and we had the localizer and glide slope captured and were following it down. After passing COLBE; the localizer again started wobbling and the flight director was chasing it back and forth causing the autopilot to turn and the aircraft to chase the CDI. By this time we had the runway in sight so I disengaged the autopilot and hand flew the aircraft down. The aircraft was slightly in an unstable approach because I was trying to get it lined back up with the centerline visually rather than with the instruments because the localizer was jumping around so much. With the rain and the runway lights on high; it made it a little more difficult to do so and I ended up landing slightly flat.There is something wrong with the localizer for 32. Two separate aircraft having the exact same problem cannot be a sheer coincidence. When it started deviating excessively we already had the runway in sight; so I disconnected the autopilot and hand flew the aircraft down on the glide slope; but visually centered up with the runway. Fix the localizer.
Air carrier First Officer reported an unreliable localizer signal for SBY Runway 32.