Another cause for debate is the claim that Preston Watson approached celebrated Brazilian aviator Alberto Santos-Dumont in 1906 and purchased from him a Dutheil Chalmers engine. In 1955, John Bell Milne made a personal assertion to Charles Gibbs-Smith that the year the motor was purchased was 1906. This could not have been possible, since Dutheil Chalmers & Cie did not construct their first aero-engine until 1907. In a later interview Bell Milne changed the date to a year later, thus bringing into question his earlier statements' validity.