GDL 90 System ICA, Helicopter STC
Garmin AT
2345 Turner Rd SE
21 December 2005
Salem, OR 97302
Part #: 560-0255-00 Rev A
©
Copyright 2005 Garmin AT All Rights Reserved
Page 9 of 13
planned replacement is not necessary. The GDL 90 “maintenance” LED will be lit when
replacement is required. The GDL 90 will also send a “low battery” message for display on
an optional controller or MFD when replacement is required. Once the low battery message
is displayed, the battery should be replaced within 1 to 2 months.
If the battery is not replaced and becomes totally discharged, the GDL 90 will remain fully
operational, but the GPS signal acquisition time may be increased. There is no loss of
function or accuracy of the GDL 90 with a discharged battery.
The battery must be replaced by the Garmin AT factory repair station or factory authorized
repair station. Refer to GDL 90 Maintenance Manual, listed under reference documentation
in paragraph 2.1 of this document, for battery replacement instructions.
2.5.3
Cleaning the GSL 71 Front Panel
The front bezel, keypad, and display can be cleaned with a soft cotton cloth dampened with
clean water. DO NOT use any chemical-cleaning agents. Care should be taken to avoid
scratching the surface of the display.
2.5.4
Altitude Encoder Calibration
The GDL 90 and/or GSL 71 are interfaced to an altitude encoder. This encoder must be
tested within the previous 24 months as specified in FAR 91.411.
2.6
Overhaul Period
The system does not require overhaul at a specific time period. Power on self-test and
continuous BIT will monitor the health of the GDL 90 UAT and GSL 71 Control Panel. If the
unit indicates an internal failure, the unit may be removed and replaced.
2.7
Troubleshooting Information
If error indications are displayed on the GSL 71, optional interfaced display/controller, or the
GDL 90 LEDs, see the ‘Troubleshooting’ sections contained in the appropriate Installation
Manuals as detailed in Section 2.1 of this document.
2.8
Removal and Replacement Information
Note: There are no special handling requirements for the GDL 90 or GSL 71.
GDL 90
To remove the GDL 90 unit from the mounting tray, turn the DZUS fastener counter-clockwise
¼ turn then pull the unit from the tray. No special extraction tools are required.
To reinstall the GDL 90, position the GDL 90 in the mounting tray and slide the unit fully into
the tray. Turn the DZUS fastener on the front bottom of the GDL 90 clockwise ¼ turn to lock in
the unit. If the DZUS fastener is hard to turn or the unit does not seat fully, the unit is probably
binding. Check the position of the unit in the mounting tray.
