The FAA has issued a Special Airworthiness Information Bulletin (SAIB) for owners of aircraft equipped with Garmin G1000, Perspective, and Prodigy Integrated Flight Decks installed with a Garmin GFC 700 autopilot.
The SAIB resulted after an issue with navigational radio auto-tune feature while performing a VOR or ILS approach was brought to the FAA’s attention.
Changes to navigation frequencies that occur between database cycle distributions may cause a mismatch between the automatically tuned LOC/ILS frequency and the frequency shown on the approach chart or applicable NOTAM. In these cases, the mismatched automatically tuned frequency may cause the HSI to automatically slew to the wrong course, according to the SAIB.
The SAIB offers several recommendations, including manually tuning the navigation receiver to the correct LOC/ILS frequency; assure that the correct inbound course is selected; manually fly the approach; or choose a different terminal procedure.
Garmin is planning resolution to this issue with GDU software version 10.00, according to the SAIB. Later versions will provide capability to couple the autopilot to the VOR or LOC/ILS approach when the pilot manually tunes the correct frequency and manually selects the proper course for the approach.
Read the full SAIB at FAA.gov