Helicopter Sikorsky H-19D Chickasaw Serial 55-985 Register 55-4937 used by US Army Aviation Army. Built 1956. Aircraft history and location Aircraft History 55-4937 US Army Aviation 1956-08-01Sikorsky S-55 c/n 55-985, ff:? del US Army as H-19D, 55-4937, 01Aug56. Send Updates Use APP to upload photo @ (optional) When Now? / / Send