Helicopter Sikorsky H-19B Chickasaw Serial 55-733 Register 52-7586 used by US Air Force USAF. Built 1954. Aircraft history and location Aircraft History 52-7586 US Air Force 1954-06-21Sikorsky S-55 c/n 55-733, ff:? del USAF as H-19B, 52-7586, 21Jun54. Send Updates Use APP to upload photo @ (optional) When Now? / / Send