First formal approval of type airworthiness of a gyroplane by the CAA (now FAA) of the USA.

Type Certificate ATC 410 was awarded to the Pitcairn PCA-2 Autogiro.

Source: "80 Years of the Autogiro: Cierva, Pitcairn and the Legacy of Rotary Wing Flight", Bruce H. Charnov, VERTIFLITE Vol. 49, No. 3, Page 40