A number range or single listed NOAA chart in iNavX fails to download, error “import failed”
Article IX14263, February 17, 2016
NOAA charts of a given number and name typically persist for years, getting revised from time to time. However, some NOAA charts are eventually retired / withdrawn and iNavX (or any other software) can no longer download those specific charts.
NOAA charts do not last forever. From time to time, a Local Notice to Mariners for a given geographic district is published with an announcement of a given chart number or number range being retired from service and no longer updated. Example: a Local Notice to Mariners of District 13, Week 46 of 2015 stated NOAA had discontinued issuing the chart with number prefix 18423 (coverage of an area by Puget Sound, NOAA west coast region). The same thing happened in 2015 for chart number 18445 and you can expect this to happen from time to time on any given year.
Once the charts are removed from the NOAA servers, any software able to download directly from the NOAA servers should retrieve whatever charts that exist and issue an error if a specific retired chart is referenced. This is the case with iNavX: if an old version of the software is in use and happens to list a chart such as 18423 then an attempt to download said chart will fail with a error message. The fix: find other charts that cover the same area and download those and/or install a new updated version of iNavX, if available, and the NOAA chart list should be revised to show only currently available charts.