The KA90 engine update kit is an engine alternative to improve King Air 90 performance. It allows the option of installing either a set of PWC PT6A-21, -28, or -34 engines to replace the original PT6A-20 engines. According to Greg Barnes, president of CenTex Aerospace, of Waco Regional Airport in Waco, Texas, “The KA90 engine update kit allows the flexibility to choose new, overhauled or engines with time remaining as replacements. Any of the three engine models will improve takeoff, climb and cruise performance.”