Design changes to resolve a manufacturing problem with the wing leading-edge anti-ice system of the Premier I were under way at press time. It was possible the modification would be installed on all affected aircraft before the June 29 compliance date of an AD that prohibits the new jet from flying into known icing until it is modified. Raytheon Aircraft discovered the airflow paths of the anti-ice system were obstructed by sealant that is applied to the wing leading edge during manufacture. This obstruction prevents hot air from properly distributing heat.