Cessna has altered the Citation X's flight manual to reflect a 400 ft reduction in landing distance and Cessna is confident that similar alterations will be published for take-off performance. Brad Thress, Citation X product marketing manager, said: "The improvement in runway performance will open up numerous airports especially to FAR Part 135 Citation X operators. Flight tests are complete for the take-off performance improvements and we expect to release another flight manual revision shortly."\rAccording to Cessna, Citation X operators have indicated that the published runway performance figures are very conservative and do not accurately reflect the capabilities of the aircraft. This prompted the manufacturer to review the data with the FAA and initiate additional flight testing to increase the accuracy of the figures.