Helicopter Sikorsky H-19B Chickasaw Serial 55-780 Register 53-4435 used by US Air Force USAF. Built 1954. Aircraft history and location Aircraft History 53-4435 US Air Force 1954-10-06Sikorsky S-55 c/n 55-780, ff:? del USAF as H-19B, 53-4435, 06Oct54. Send Updates Use APP to upload photo @ (optional) When Now? / / Send