Garmin GNC 420AW Installation Manual - page 42
Page 2-12
400W Series Installation Manual
Rev. E
190-00356-02
2.9
Installation Approval Considerations
In most cases, AML STC SA01933LA only covers the interfaces in Appendix G. However, as described
in the following sections, specific interfaces not listed in Appendix G can be approved under AML STC
SA01933LA.
2.9.1 Autopilot Interface Approval
The 400W Series units have been approved to interface with a number of autopilots. Autopilots that will
be coupled to GPS
vertical
guidance for GPS approaches
must
be specifically listed in Appendix G.
Autopilots not listed in Appendix G can still be approved under 400W/500W Series AML STC
SA01933LA if
all
of the following conditions are met:
•
The installation of the autopilot was previously FAA-approved;
•
All interfaces between the 400W Series unit and the autopilot are analog;
•
The installation must use existing navigation signals which interface the autopilot to a standard
VHF navigation receiver (i.e. CDI/HSI L/R and Up/Dn)
•
A successful in-air flight check must be completed prior to returning the aircraft to service.
•
The AFMS is properly completed, limiting the GPS to lateral coupling only (LNAV)
If these conditions are met the interface can be approved under AML STC SA01933LA. These
autopilots are limited to those operations for which they were previously FAA-approved when interfaced
with the other TC’d or STC’d navigation units (e.g. if the previous unit was installed and approved for
coupled VOR, ILS, LOC, BC and GPS LNAV approaches, this upgraded installation will also be
approved for these operations; however, GPS and RNAV approaches with GPS/WAAS-based vertical
guidance (LNAV+V,L/VNAV and LPV modes on the 400W series unit) are not authorized when
coupled to the autopilot).
NOTE
Contact Garmin to remove VNAV limitations.
2.9.2 Altitude Encoder/Air Data Computer Interface Approval
The 400W Series units have been approved to interface with a number of altitude encoders. However,
altitude encoders not listed in Appendix G can still be approved under 400W/500W Series AML STC
SA01933LA if
all
of the following conditions are met:
•
The altitude encoder/air data computer is TSO approved;
•
The installation of the altitude encoder / air data computer was previously FAA-approved;
•
The interface check for the altitude encoder described in section 5.4.4 (serial interface) or 5.4.5
(parallel/gray code interface) of the applicable 400W/500W installation manual must be
successfully completed.
If these conditions are met the interface can be approved under AML STC SA01933LA.
2.9.3 Audio Panel Interface Approval
The 400W Series units have been approved to interface with a number of audio panels. However, audio
panels not listed in Appendix G can still be approved under 400W/500W Series AML STC SA01933LA
if
all
of the following conditions are met:
•
The installation of the audio panel was previously FAA-approved;