The FAA has issued a special airworthiness information bulletin (SAIB) warning operators of Garmin G1000 avionics suites with GFC 700 autopilots. The SAIB warns of possible issues related to the system's auto-tune functionality. The alert includes Cirrus's G1000-based Perspective flight deck and Prodigy Integrated Flight Decks, as well. There are cases where the nav portion of the avionics might switch automatically to a localizer or VOR frequency that might have subsequently been changed via NOTAM or other revision unrecognized within the navigator's database. And even if the pilot manually tunes the correct frequency, the autopilot will not capture or track the altered signal. Nor will the flight director track the manually changed signal. The FAA recommends that the pilot manually set the correct frequency and then hand-fly the approach; or choose another approach at the airport. Garmin announced plans to correct the issue with a future software update to version 10.0, which will allow the flight director and autopilot to accept manually set frequencies.