REDUCER

The MS21916D6-4 is a genuine Textron Aviation reducer supplied for use on the aircraft, with its precise function defined by the aircraft's parts data. It is applicable to the Citation III, VI or VII, Citation V, Ultra, Encore or Encore+, Citation X, and Citation X+. It carries an export classification of ECCN EAR99, weighs 0.03 lbs, and measures 2.65 (L) x 0.95 (W) x 1.2 (H) in. Because the MS21916D6-4 is an original-equipment (OEM) part sourced directly from Textron Aviation, it matches the exact specification and placement called out in the aircraft's type design and maintenance data — assurance a generic substitute cannot offer. Across the Cessna Citation fleet, correctly identified factory parts like this keep every airframe consistent and configuration-correct. As a factory-supplied item for a type-certificated aircraft, this part is defined by the manufacturer's specification and applicability data. The value of an OEM part is as much in its paperwork and pedigree as its metal — both of which an aircraft's records require. Cessna traces to the company Clyde Cessna founded in Wichita, Kansas in 1927; Textron Inc. acquired it in 1992, and since 2014 it has anchored Textron Aviation alongside Beechcraft and Hawker. Cessna's Citation line, launched with the Model 500 in the early 1970s, grew into the best-selling business-jet family in the world, spanning today from the light M2 to the super-midsize Longitude. To check availability, request a quote for MS21916D6-4 or browse more Cessna Citation parts on Flying411.