Cessna designers working on the Citation Encore programme have introduced a number of enhance-ments to the aircraft's specification, but at the price of delaying certification and deliveries by around six months. The Encore was first announced at the NBAA convention last year, and is a further evolution of the Citation V and Ultra. The original schedule would have seen customer deliveries begin in the second quarter of 2000, but this landmark is now expected to take place in the fourth quarter.\rKey improvements over the Citation Ultra include trailing link landing gear, bleed air anti-ice wing leading edges and PW535A engines. During the course of flight testing and certification engineers have been able to 'fine tune' the aircraft's configuration, says Cessna. As a result the Encore will be a quieter aircraft: Six-key brakes have been added, which are both quieter and more effective, and new fairings have been developed for the main landing gear to reduce drag and cabin noise levels. As part of an aerodynamic optimisation effort a fourteen inch wing tip extension has been designed and will be installed, improving climb, cruise and runway performance.\rThe engines for the Encore remain as originally specified, Pratt & Whitney PW535A. These are rated at 3,400lbs of thrust to 80 degrees Fahrenheit (12 per cent up compared to the JT15D-5D engines used on the current Ultra model), and will deliver a 15 per cent reduction in specific fuel consumption. Certification is now expected to be complete by the second quarter of 2000.