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Aviation Alerts and Advisories

GDL 84/88 Software Upgrade to System Software Version 3.40


All GDL 84/88 units are affected.


TSO Authorization


Mandatory for all GDL 88D (diversity) units with Software Version 3.34 only.

Optional for all other units.


This modification is warranty reimbursable for GDL 88D (diversity) units with Software Version 3.34 (with a deadline of November 16, 2018).

This modification is not warranty reimbursable for non-diversity GDL 84/88 installations.


GDL 84/88 System Software Version 3.40 contains the following changes:

  • Fixed GDL 84/88 Application Software v3.34 antenna selection issue that can cause GDL 88D (diversity) units to select the incorrect antenna.
  • Fixed FIS-B processing issues that could result is loss or partial loss of FIS-B data.
  • Updated built-in test monitors to reduce nuisance failures and improved fault logging capabilities.
  • Updated traffic processing library to improve TCAS integration, improve TIS-B track handling, improve traffic source correlation, improve traffic prioritization/selection, and reduce nuisance traffic alerts.
  • Added proprietary traffic, position, air data, and control interfaces for third party OEM customer.
  • Updated ARINC 743A output to include label 141 (UTC Fine).