Helicopter Sikorsky S-55C Serial 55-1239 Register used by Mitsubishi (Mitsubishi Heavy Industries). Built 1958. Aircraft history and location Aircraft History n/a Mitsubishi 1958-12-04Sikorsky S-55C, c/n 55-1239 del Mitsubishi in kit form, 04Dec58 assembled as Mitsubishi S-55C, M55-???, unk. Send Updates Use APP to upload photo @ (optional) When Now? / / Send