Garmin GNS480

The GNS 480 is aviation’s first Gamma-3 WAAS-certified GPS/Comm navigator. It’s loaded with features and guidance capabilities that put it at the forefront of panel-mount navigation technology at the time of its release by Apollo as the CNX80 and subsequently purchased by Garmin 2003 and released as the GNS480 https://en.wikipedia.org/wiki/Garmin.

The database card started out as a 32 MB partition and has been subsequently increased to greater than 64 MB due to the increase in US data of:

way-points,
approaches,
arrivals and
departures.

The GPS uses a FAT16 formatted Flash Card which uses the partition serial number as the volume id, and is labelled with CNX 80.

An example GNS480 compact flash database card contains:

partition: GUUID=78CD-C85D
label: CNX 80
contents :

  System Volume Information/WPSettings.dat
  System Volume Information/IndexerVolumeGuid
  database/nav/XXX-YYY.bia 
  database/nav/XX-YYY.bib
  upsat/info.dat

optional contents

  [feat_unlk.dat]

inspecting

The card should be imaged for preservation and restoration in case something should happen to the Compact Flash card and the file system be damaged.

Plug the CompactFlash Card into your reader and look for the device (and take note):

on linux

sudo fdisk -l

obtain the volume id on Linux

sudo blkid

or obtain the volume id on Windows

vol drive-letter:

backup and restore on linux

the image may be saved on linux (take care with if and of targets so you do not overwrite your original card while making the image) via:

 dd if=/dev/SDFlash-device of=gsn480.img bs=4048

the image may be restore on linux via e.g.

 dd of=/dev/SDFlash-dev if=gns480.img bs=4048

Disclaimer: you do this at your own risk and responsibility.

backup and restore on Windows

use Win32DiskImager https://sourceforge.net/projects/win32diskimager/

Disclaimer: you do this at your own risk and responsibility.

why

This article was written because I had to restore a friend's data card for his aircraft. You should make a backup because these cards are not infallible and getting a replacement with the Garmin contents on them for a now unsupported system is like trying to find hen's teeth. His compact datacard was electrically destoyed because a pin bent over in the card-reader carrier that was being used to load Nav data to the card - but the card could have easily died due to old age. That card was mis-reporting its partition size and had a corrupted index and could no longer be read or written properly. So the former contents had to be found to build a new card - luckily the www community helped out as Garmin said they could not.

Stop-press 2020-07-20

I also had a Garmin G500 (Gdu620) sdcard fail last month. It was nearly 12 years old and suffering from too much insertion and removal. Being in the IT industry I know that Flash and SdCards fail.

Make sure you have spare cards and you back them up because you never know when one is about to fail, and it will do so at an inconvenient time - like after you start the aeroplane and when you are about to embark on an IFR flight. Also have data subscriptions that let you re-load your current aircraft data once you obtain your replacement card.

I have backups for all my data cards in case I get stuck in the boon-docks. Even the cards for my operational raspberry-pi SBC systems, as well as backups of all my critical server partitions - which I store in one of my NAS along with backups of my mediawikis and the source code repositories and all the other critical company information (even including this wiki is automatically backed-up - as are all the others - on encrypted drives).

Garmin GNS480 data card