Aviation Alerts and Advisories

Service Bulletin 1368: Software Upgrade for GDU 620 Software Version 6.21 and GAD 43e Software Version 2.20

19 December 2013  / Service Document Notifications /

CERTIFICATION APPROVAL: TSO Authorization (see Approval section of SSB1368 for details)


This Service Bulletin is mandatory and is warranty reimbursable.


This Software Service Bulletin announces availability GDU 620 Software Version 6.21 and GAD 43e Software Version 2.20.

Software Updates:

  • GDU 620 Software Version 6.21 contains the following changes from version 6.11:
    • KAS 297 altitude preselector emulation support
    • Resolves issue identified in Service Advisory 1361
  • GAD 43e Software Version 2.20 contains the following changes from version 2.12:
    • KAS 297 altitude preselect emulation for KFC200/250 autopilot systems
    • Resolves parallel DME tuning issue

Service Bulletin 1306, disabling G600/GAD 43e DME configurations which utilize KN-63 parallel tuning, is
addressed by GAD 43e Software Version 2.20. Parallel tuning may be configured and restored as specified in the installation guidance.

Service Advisory 1361, possible temporary loss of heading/attitude information in Garmin G500 and G600 Systems following extended power-on stall and slow flight maneuvers, is addressed by GDU 620 Software Version 6.21.


Refer to  ASDN1368


Refer to STC Service Bulletin No. 1367 for instructions for loading the software in the GDU 620, GAD 43e units, and a description of the TSO authorized changes. Garmin plans to distribute STC Service Bulletins once the G500 Part 23 AML STC and G600 Part 23 AML STC have been amended to provide installation approval.