Helicopter Sikorsky S-55 Serial 55-881 Register N411A SE-HBB used by osterman helikopter. Built 1955. Aircraft history and location Aircraft History SE-HBB osterman helikopter 1955-06-16Sikorsky S-55 c/n 55-881, ff:? del Osterman Aero AS as SE-HBB, 16Jun55. For N411A see also 1955 S-55 55-890 N411A - ex SE-HBB Send Updates Use APP to upload photo @ (optional) When Now? / / Send