January 18, 2016
Owners/Operators of G1000 Equipped Twin Commanders, Twin Otters, Diamond DA 62s, Bell 407s, TBM 850/900s, and Piper M350s
SUBJECT: AFCS armed mode cancellation
Garmin G1000 systems installed in the following aircraft with the specified GDU software versions listed
below are affected.
- Twin Commander with GDU software version 15.01
- Twin Otter with GDU software version 15.01
- Diamond DA 62 with GDU software version 15.00
- Bell 407 with GDU software version 15.02
- TBM 850/900 with GDU software version 15.00
- Piper M350 with GDU software version 15.01
If the AFCS is coupled to GPS NAV and the autopilot Approach mode is armed for an ILS, LOC, LDA, or SDF approach, sometimes the armed LOC and GS AFCS modes are cancelled when the NAV source transitions from GPS to LOC mode on the HSI. When this occurs, the LOC and GS armed modes are removed from the AFCS mode annunciation window and the system continues to navigate in GPS NAV mode. If no action is taken, such as pressing the APR Key on the AFCS Mode Controller to arm LOC and
GS modes, the system will continue to navigate in GPS NAV mode until crossing the FAF. At the FAF, the AFCS lateral mode will change from GPS to ROL mode because the localizer has not been captured. When AFCS NAV mode is used instead of Approach mode when flying a Localizer approach, the AFCS lateral mode may not automatically switch from GPS to LOC mode when the NAV source transitions to LOC.
The issue can be avoided by flying the approach using Vectors-To-Final. When flying an ILS, LOC, LDA, or SDF approach using AFCS Approach mode, and the LOC mode armed annunciation is removed from the AFCS mode annunciation window when lateral navigation changes from GPS to the LOC NAV source, press the APR key to arm LOC and GS modes. When using AFCS NAV mode to fly a localizer approach, and LOC mode does not arm when lateral navigation changes from GPS to the LOC NAV source, press the NAV key to activate ROL mode as the AFCS lateral mode. Press the NAV key again to activate LOC mode as the AFCS lateral mode.
A future software release will correct this issue.
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