Special-mission and Heavy-duty Mods Are Avcon Industries’ Specialties

When it comes to unzipping the belly of a Beechcraft King Air to install a sophisticated camera system or modifying classic Learjets with modern radios and new hushkits, the team at Avcon Industries in Newton, Kan., knows exactly what it takes to get such a project done.

There is a lot more to Avcon (Booth No. C7819), a subsidiary of Butler National, and a visit to the company’s Newton facilities revealed a plethora of projects that have kept the company’s engineers and technicians busy nonstop for many years. In the special-mission field alone, Avcon owns 250 supplemental type certificates (STCs). The latest effort is a hush kit for Learjet 20-series jets powered by GE CJ610 engines. A Learjet 24 with the hush kits and dual Garmin GTN 750 navigators is at Avcon’s static display spot at Henderson Executive Airport.

Inside the main hangar in Newton, a couple of King Airs were in the midst of Avcon’s belly camera STC treatment, which involves a significant dismantling of the pressurized fuselage’s structure. The camera itself, used for aerial surveying, sits safely behind a $30,000 piece of super-strong BK-7 optical glass mounted into a structural frame installed in the belly. The camera STC is available on a variety of airplanes, including King Airs, Learjet 20 and 30 series and the Cessna Citation II and Conquest II.

For fans of older Learjets, from the 20-series through the popular Learjet 35, Avcon is the go-to solver of challenging problems. Current Learjet 20/30-series upgrades include a dual Garmin GTN 750 panel mod, which adds Waas LPV touch-screen navigators to the older Learjets.

Avcon also offers the R/X range-extension mod for the Learjet 35/36. This STC simply extends the length of the Learjet’s tip tanks by 36 inches, adding 750 pounds of usable fuel (about 40 minutes of flight time at normal cruise speeds). The tanks add other benefits, including increased stability, which eliminates the need for yaw dampers for dispatch, and the opportunity to add weight-increase STCs (which may require installation of a heavier landing gear on some earlier models). On the Learjet 35 and 36, range grows to more than 2,100 and 2,800 nm, respectively.

The weight increase mods can also be installed on the Learjet 35/36 without the extended tip tanks, by incorporating the Avcon Fins delta-shaped fins on the aft lower fuselage. The fins mod also eliminates the need for operable yaw dampers.

The dual Garmin GTN 750 mod for the Learjets is done by Avcon sister company Kings Avionics in New Century, Kan. The Garmins replace the Learjet’s Universal UNS-1N FMS, and the GTN 750s are hooked up to the Learjet’s FC-200 autopilot, allowing roll- and GPS-steering. The jet’s original “iron gyros” are retained.

Avcon’s Newton facility is self-contained when it comes to all the heavy duty sheet-metal and component work that its technicians accomplish. The company owns three CNC machines, makes its own wire harnesses and even built its own test rig for the tests needed after overhauling Learjet stabilizer actuators, which need to be done every 600 hours.

The new hush kit is designed to help keep CJ610-powered 20-series Learjets flying after the Dec. 31, 2015, Stage 3 mandate takes effect in the U.S. Avcon expects the hush-kit STC to be issued shortly, and this will cover most of the 350 Learjet 20-series still in service, except for those with the unmodified straight-wing and Dee Howard XR-wing, which will be subject to a later STC.