Helicopter Sikorsky H-19D Chickasaw Serial 55-996 Register 55-4944 used by US Army Aviation Army. Built 1956. Aircraft history and location Aircraft History 55-4944 US Army Aviation 1956-08-02Sikorsky S-55 c/n 55-996, ff:? del US Army as H-19D, 55-4944, 02Aug56. Send Updates Use APP to upload photo @ (optional) When Now? / / Send