Helicopter Sikorsky S-55 Serial 55-897 Register N746A used by Humble Oil and Refining Company. Built 1956. Aircraft history and location Aircraft History N746A Humble Oil and Refining Company Sikorsky S-55 c/n 55-897, ff:? del Humble Oil as N746A, 1956. Send Updates Use APP to upload photo @ (optional) When Now? / / Send
