Helicopter Sikorsky H-19D Chickasaw Serial 55-994 Register 55-4942 used by US Army Aviation Army. Built 1956. Aircraft history and location Aircraft History 55-4942 US Army Aviation 1956-08-02Sikorsky S-55 c/n 55-994, ff:? del US Army as H-19D, 55-4942, 02Aug56. Send Updates Use APP to upload photo @ (optional) When Now? / / Send