Maintenance and Modifications
Learjet 20 XR Mods Now Have Hushkit
Deadline for Stage 3 noise compliance was Dec. 31, 2015, and now all Learjet 20 series can be modified to meet the requirement.

Butler National subsidiary Avcon Industries has added the Learjet 20 series with the XR wing modification to its hushkit supplemental type certificate (STC), and now all models of the Learjet 24 and 25 can meet the Dec. 31, 2015 Stage 3 noise limits. The modification does not restrict maximum operating altitudes of all of the Learjet 24/25 models, which includes the straight wing, Mark II, XR and Century III, according to Avcon.