PURPOSE

This Service Advisory provides notification that revisions to the Instructions for Continued Airworthiness
(ICA) have been published for the GDL 90 Data Link Sensor. STCs SA02217AK and SR01863LA for the
GDL 90 UAT require that Garmin provide notification to installers and customers of revisions to the ICA.

DESCRIPTION

The periodic maintenance of the GDL 90 UAT must include a check of the pressure altitude source within the previous 24 months. The revised ICA clarifies the procedure for periodic test and inspection of the altitude source. Details can be found in GDL 90 UAT Data Link Sensor System Instructions for Continued Airworthiness, Garmin AT p/n 560-0279-01 Rev C, dated September 19, 2007, or GDL 90 System Instructions for Continued Airworthiness Helicopter STC (AS-350 Series), Garmin AT p/n 560-0255-00 Rev C, dated September 11, 2007.

PRODUCTS AFFECTED

The information provided herein applies to all models of the GDL 90 UAT Data Link Sensor (Garmin AT
p/n 430-6081-100-xxx) installed in accordance with the SA02217AK or SR01863LA STC.

REFERENCES

GDL 90 UAT Data Link Sensor System Instructions for Continued Airworthiness (Garmin AT p/n 560-0279-01 Rev C)
GDL 90 System Instructions for Continued Airworthiness Helicopter STC (AS-350 Series) (Garmin AT p/n 560-0255-00 Rev C)
GDL 90 UAT Data Link Sensor Installation Manual (Garmin AT p/n 560-1049-02 Rev C or later)

ADDITIONAL INFORMATION

Details of the changes to the ICA can be found in the ICA’s latest revision. Authorized Garmin
Distributors will find the ICA contained in the GDL 90 STC Kit which can be downloaded from the Dealer
Resource area of the Garmin website. Other operators and installers may obtain electronic or hard
copies of the ICA from Garmin AT Technical Support by calling:
US – 800.525.6726 ext. 3991, CAN – 800.654.3415 ext. 3991, INT – 503.391.3411 ext 3991.
Please request the ICA using the description and part number shown above in the References Section of
this Advisory.