N220RB was a very early production DC-8 and was first delivered to United Airlines in June 1960. After serving with the airline for 20 years it was donated to Project Orbis in 1980, for use as a flying eye hospital teaching surgical skills to eye doctors in developing countries around the world. It was eventually replaced in this role by a DC-10 in 1994, whereupon it was retired to the China Aviation Museum to become one of the more unusual exhibits here.