lml@lancaironline.net Mailing List Archive

If anyone with a L-3 Stormscope interfaced to their Chelton is experiencing the problems or issues noted by Hal Woodruff or Jeff Edwards, please contact your panel builder or qualified avionics shop to discuss the resolution. After speaking with the shop that built Jeff Edwards panel yesterday, we've learned that the stormscope has been installed improperly. Although in-flight operation should be correct in this configuration, all maintenance and testing modes will be disabled. The installation of the L-3 stormscope to the Chelton EFIS was tested and approved by L-3 at their testing facility by their engineers and has been approved and certified by the FAA as well as the new 5.0A software that is currently being distributed. Below is an explaination from Robert Durall, Manager of Chelton Flight Systems Avionics Dept:

"The Chelton EFIS is designed to be the primary controller for the L-3 Stormscope computer. In this mode, all heading information and mode control are provided by the EFIS to allow the strike information to sync with the EFIS display. The EFIS sends heading information from the AHRS to the Stormscope computer first, then if there is no AHRS data, the GPS Track from the GPS receiver.

A number of other GPS receivers (such as the Garmin GPS 430/530) send a heading of 0 degrees when the ground speed calculated from the GPS is below a specific value. This reduces the errors induced due to Selective Availability on the GPS receiver when the aircraft is setting on the ground.

The difference between the heading from the EFIS and the GPS Track from the external GPS receiver can vary greatly and in some cases irratically. This is normal.

Chelton Technical Support requires that the Stromscope be controlled directly from the EFIS rather than an external GPS receiver. In this installation, the EFIS provides every maintenance function for the computer and can place the computer in every mode of operation.

If the aircraft contains both the Chelton EFIS and another GPS source that outputs a heading of 0 degrees when on the ground (such as the Garmin 430/530), the way to test both systems correctly is to place the PFD of the EFIS into the Ground Maintenance mode then select the WX-500 Maintenance Utility. In this mode, the EFIS will output a 0 degree heading reference to the Stromscope and both the EFIS and the external GPS receiver will see the test strike data at the same position."

The technician from L3 that was assisting with stormscope problems at the Lancair Fly-In SHOULD have confirmed that the stormscope had been installed and wired properly rather than pointing to an improper interface. Had he researched his display approval list and installation documents, it would be reasonable to at least question the installation IMO.

If you want to test your stormscope through your Chelton to verify proper operation, you can utilize the WX-500 maintenance utility built into your system. Insert your Smartmedia Card, power up your system, and select the utility.

If you suspect your system is improperly wired, please contact your authorized avionics shop asap.

Chelton Flight Systems and Direct-To Avionics is committed to providing the finest navigation equipment available (at any price). Nobody else in the aviation industry can provide a more reliable EFIS platform with certified level software. This is just one example of why certified software is beneficial to experimental aircraft pilots.

Kirk Hammersmith
President
Direct-To Avionics, LLC
541.504.8300 v
775.416.3222 f
www.direct2avionics.com