The US Federal Aviation Administration has issued an airworthiness directive making terrain-awareness warning systems (TAWS) compulsory in all US turbine-powered aircraft with six or more passenger seats. Aircraft built before 29 March, 2002, must have the appropriate equipment by 29 March, 2005, and aircraft manufactured from the end of March 2002 must be supplied with TAWS installed.
Non-commercial turbine-powered aircraft with six or more seats must have enhanced ground proximity warning systems. Commercial aircraft with six to nine seats have the same requirement, but turbine aircraft with more than nine seats must have "Class A" TAWS, with terrain awareness.
Source: Flight International
