Lingering technical issues are forcing Garmin to delay plans for upgraded WAAS capability in the company's GNS 430/530 and GPS 400/500 panel-mount avionics, according to a spokesman. Explaining that the upgrades will require "a major software rewrite" in addition to minor hardware changes, the spokesman indicated that the capability is now not expected to be available before next year's third quarter. "Unfortunately and regrettably we have had to alter the time schedule for this important project," he said. The spokesman added that the cost of the upgrade remains $1,500 as announced previously. Owners must sign up for the upgrade with Garmin by November, but do not have to pay for it until the work is completed. When the WAAS modification package is ready, owners will need to send their units to Garmin for the hardware changes and the WAAS software. The wide-area augmentation system is an FAA-run satellite and ground station network designed to improve the accuracy of GPS satellite signals.