The 400/500W units with WAAS capability offer many new features and enhancements over the classic models. Some enhancements include WAAS enable GPS antenna, receiver, and software. The 400W/500W series units comply with WAAS TSO C146a and include hardware upgrades with a faster micro-processor. A terrain database for terrain awareness is included a standard feature. Most importantly, the WAAS GPS receiver allows pilots to use the GNS-400W/500W units for primary navigation and vertical guidance for LPV, L/VNAV, and LNAV+V approaches.
For a complete summary of the feature changes and enhancements, click Here.