The prototype Howard 500, which however was not converted to full Howard 500 standard. It received an experimental C of A as a Howard 400 in Sep 1959 as N100M, and was later called the Howard Pressurised Ventura.

Built in 1943 for US Navy as PV-1 BuAer 34607 but diverted to Canada as RCAF 2228. Sold to USA in 1951. Converted by Howard Aero in 1959 to Howard 500 but registered as a Howard 400. Stored at FLL from 1977.

This is the prototype Howard 500, which however was not converted to full Howard 500 standard. It received an experimental CofA as a Howard 400 in Sep 1959 as N100M, and was later called the Howard Pressurised Ventura.