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ClearNav News

April 7, 2019 - NEW CNII Software Ver. Released

Clear Nav is pleased to release a new software update for ClearNav II flight computer.   The release notes are included in the download.  Though there have been no major features added, this is a first crucial step towards continued development and support for the ClearNav  brand. 
Many thanks to Mike Bell, whose tireless curiosity and efforts over the past few months have resulted in several performance enhancements and fixed a couple of fairly serious computer “crash” exposures. 
ClearNav is committed to further development and support of this uniquely simple yet capable soaring flight computer system and Variometer.


May 11, 2018 - NEW CNv Software Ver. 3.6.4512 Released

This is a maintenance release, building on the previous 3.6 release, 3.6.4250 (Feb 2017), which it replaces. It contains a couple of fixes. There is no significant new functionality and, unless you have experienced any of the issues mentioned below, it is probably not worth upgrading from 3.6.4250.

However, if you are upgrading from any other older release (pre 3.6) then you should use this latest version (3.6.4512) and also read the general release notes for 3.6 (below).

Volume Control Problem

A rare issue which could occur if the vario is power cycled quickly.

Symptoms: the vario would be unresponsive for a long pause, with the display saying "WARNING: NO ADC!", followed by "Fault code 6 (Volume)" and the audio stuck at maximum volume.

The fix in this release gets rid of the long pause, but cannot fix the underlying problem.

If this issue occurs now, the vario will quickly report "Fault code 6 (Volume)". The workaround is simple - power cycle more slowly, leaving the power off for more than a second or two.

Software Update Problem

A software update problem which could occur when updating from some old versions of the software to CNv-3.6.4250. When it occurred displays may not update to the new version and it was possible to leave the display without an application – in which case it appears dead.

The fix in this release completely resolves this issue and, even if the display appeared dead, applying this software release will bring it back to life.

CNv 3.6 Release - General Comments

The 3.6 release incorporates all changes made since the last public release, 3.3.3899. This includes the final versions of changes made during the 3.5.x beta releases.

To use all the features in this release, you MUST use a profile which has been produced from the CNvUtility 3.6.2 which is also available on the ClearNav website. See the CNvUtility 3.6.2 Release Notes and Instructions.
Be sure to follow the Instructions for software and Utility installation.

The improvements in this release have been focused on supporting the pilot in flying faster – better cruising, better support for the decision of when to stop and climb, improved cruise/climb transition, and better cruise/climb averages.

For more details please see the online manuals:

Recommended Initial Setup

Create a profile in the CNvUtility 3.6.2 or onwards. On the Vario page, select the set of options as shown in the in the illustration in the CNvUtility Release Notes.

In the CNv (Vario Settings Ribbon) set the cruise time constant to 10 seconds. This affects the cruise averages, the rate of change of the STF number, and the initial climb average after switching to climb.

Also in the Vario Settings Ribbon, set the audio and pointer time constants to a value between 0.6 – 1.0 seconds.

After gaining some experience with this software, the various settings may be adjusted to meet your needs.


Visit the Software Download Page and download both new releases.

  1. CNv software version 3.6.512 - be sure to read release notes!

  2. CNv Utility ver. 3.6.2 - no change

A profile generated with the CNvUtility v3.6.2  is required to use v 3.6.4250 and LATER software.


February 9, 2017 - ClearNav CNv NavDisplay XC Manual Updated

The new manual updates cover Release 3.6.4250 and onwards. View CNv XC Manual Pages


February 1, 2017 - Clear Nav Instruments Under New Management

Effective Feb 1 2017.  Clear Nav Instruments Inc. has been sold to and is now under the ownership of Rex and Noelle Mayes of Williams Soaring Center (WSC) located in Williams Ca.  The  development, manufacture, assembly, distribution, support and repair operations will be head quartered at Williams Soaring Center.

Gary Kammerer  remains available for support and repair services in his new location in Vermont.  Chip Garner, David Masson and Angus Raby will remain on the development team.   Richard Kellerman and Tim Welles remain committed to serve in consulting roles for the purpose of  mechanical engineering and testing.

There are no immediate plans to change the dealer net work.

Rex and Noelle are excited about the future of the ClearNav line of soaring instruments and are committed to the continued research and development to produce this state of the art equipment.

Please visit to learn more about Rex and Noelle and the WSC family of soaring services.


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2668 Husted Road Williams, CA  95987  USA
Phone: 530-473-5600