CN CNi  



ClearNav Service

CNI to CNII Upgrades Only

Contact Richard Kellerman ( and schedule a date and ship to the address following.  Only the ClearNav display needs to be returned – the Nexus box and controller can stay in your glider. 

ClearNav Instruments
256 Old Kennett Road
Kennett Square, PA 19348

All other Service

We will be making some changes to the way we handle support for ClearNav and CAI products and request that anyone needing service contact Gary prior to shipping any instrument.

Gary Kammerer
ClearNav/Cambridge Service/Support
144 Daltons Rd
Waterbury, VT 05676

Gary Kammerer - Customer Service


Cambridge Model 10/20/25 and 302 Garmin UTC Repair Pricing

Model 10/20/25 Repair --- Repair includes opening the receiver, replacing the Garmin internal 3v lithium re-chargeable battery with a new one, re-setting the UTC date and performing a barograph calibration. A label will be placed on the unit to remind you to power the unit overnight during lengthy periods of non-use (4 or more months) ... this will recharge the Garmin battery so the UTC date does not fail. Cost: $175.00

Model 302 Repair---The Garmin receiver will be replaced with a new Garmin receiver that does not have the date issue. The repair will include a barograph calibration and a 1 year warranty. Cost: $350.00 + S/H.

Model 302 Exchange --- If it’s time to upgrade your vario/air data computer to the next generation, in exchange for your 302we will ship you a new state-of-the-art XC ClearNav Vario (0620 + 0628) at a 25% discount. Total: $1537.50

Cambridge Legacy Service

ClearNav Instruments is pleased to announce that we will be providing repair and calibration services for the following Cambridge Aero Instruments products:

Cambridge Logo

300 Series Instruments

GPS-NAV™ Recorder

GPS-NAV™ Display

L-NAV™ Glide Computer

S-NAV™ Glide Computer

CAVII™ Variometer

CNI will also evaluate and service cabling and accessories associated with the above instruments.

CAI 302 Repair Policy

Effective immediately (9/27/2014) we are moving to a fixed price service policy.  For $350* we will:

  • Repair almost any 302**
  • Clean and test and inspect as appropriate, connectors, boards and components
  • Calibrate the altitude pressure transducer and provide a new calibration certificate
  • Issue a full one-year warranty to cover the entire instrument, not merely the repaired item(s)

*There will be a minimum charge of $125.00 if no defects are found and the unit is determined to be functioning perfectly.
**Almost any – we reserve the right to return at no cost any instrument which we judge not repairable – for example if you drove the trailer over it or filled it with water in a water landing.

Standard Services and Rates

CNI’s service department rate for all repairs is $90 per hour, with a minimum $75 charge for any unit accepted for test and evaluation.

The standard rate for calibration of your GPS-NAV, L-NAV or S-NAV is $75. Calibration of your GPS-NAV Datalogger will include a Barograph Calibration Certificate in approved IGC format. Standard calibration turnaround for a pre-authorized and paid calibration is five business days or less. RUSH service (two day or better turnaround) is available for an additional fee of $50. If additional service is required at the time of calibration, total time and materials will be billed at the $90/hour rate, including the time spent on calibration.

CNI is also pleased to offer firmware upgrades to the most current version available for GPS-NAV Dataloggers and L-NAV/S-NAV Glide Computers. Firmware upgrades are offered at a flat rate of $75.

Note that while CNI is well stocked with components for the above products, there may be some repairs we are unable to perform because of part obsolescence. In this event, the product will be returned to you in the condition received and you will be billed for our test and evaluation time (minimum $75).

How to Return an Instrument

All repair and calibration services will be performed under the supervision of Gary Kammerer. Gary is a former Cambridge Aero Instruments employee and has years of experience providing service and support to the above instruments. Contact Gary by e-mail or phone to discuss your problem and service procedures. Gary is available to trouble-shoot your legacy Cambridge product Monday to Friday from 9 to 5 EST at 802-882-8530. Gary can also be reached by email at

Please note that CNI is not able to provide general technical support relating to use of these instruments. For manuals and reference materials, you can visit the Cambridge Aero support site or Dickie Feakes’ Bicaster Aviation site in the UK. For paid phone and web-conferenced technical support, you may also contact Paul Remde at Cumulus Soaring.

You can also view in-depth demos of the GPS-NAV and L-NAV on the Cumulus Soaring download page:

GPS-NAV Demo/Training Files L-NAV Demo/Training Files

These demos can provide an excellent introduction if you have purchased one of these products from another pilot.

Cambridge Aero Instruments, the Cambridge Logo, GPS-NAV, L-NAV, S-NAV and CAV-II are licensed trademarks of R-Track Technologies, Inc., Memphis, TN.

Copyright © 2017 ClearNav Instruments. All rights reserved. Website by DesignTeKK.