from school, beisiegel went as a cadet to the royal air force college cranwell where he graduated as a pilot officer in december 1927. he was promoted from flying officer to flight lieutenant in 1933. this was followed by promotion from flight lieutenant to squadron leader in 1937. from the outbreak of the second world war in september 1939 to may 1940, he was in charge of no. 616 squadron raf, a unit that was equipped with the mark i spitfire during his command and that was based at raf leconfield until deployed south in may 1940. in 1942, he was temporarily promoted from wing commander to group captain under the heading of "general duties". he remained in the raf after the second world war and was then officially promoted from wing commander to group captain in 1947. in 1950, he was awarded the obe in the king's birthday honours. he retired from the raf with a promotion to the rank of air commodore in 1956.