Polish born Wladyslaw &quot;Spud&quot; Potocki took over Arrow test flights following Jan Zurakowski&#x27;s retirement from active test flying in Sept 1958. Following emigration to Canada in the early 1950s, Potocki was engaged as a test pilot with &quot;Avro Aircraft Canada Ltd&quot;. He accumulated the highest number of hours of the four pilots who flew the first five Arrow aircraft. It was recorded that he reached a speed of Mach 1.9 in one of the Arrows, but it was rumoured that he actually reached Mach 2.0.