Family background Johnsen was born in Bromley, Hertfordshire, the son of Wilhelm Martin and Eliza Johnsen. and was absorbed into the establishment on 17 November. He was promoted to lieutenant on 1 July 1914, and to captain on 29 April 1917, with precedence from 1 June 1916. Johnsen was seconded to the Royal Flying Corps, in which he was appointed a flying officer on 7 July 1917, with the rank of lieutenant (honorary captain). He was posted to
No. 98 Squadron RFC, flying the
DH.9 two-seater day-bomber. Johnsen's first victory came on 11 July 1918, by driving down out of control a
Pfalz D.III over
Don. On 18 July he destroyed an
Albatros D.V over
Fère-en-Tardenois, and on 20 July shot down a
Fokker Dr.I in flames. For these first three victories he flew with observer Captain G. H. Whitfield. His fourth victory came on 30 August, driving down a
Fokker D.VII over
Somain, with observer 2nd Lieutenant A. H. Fuller, and he repeated this feat for his fifth and final victory on 16 September over
Oisy, with observer 2nd Lieutenant C. H. Thompson. He received his medal from the King at
Buckingham Palace on 24 July 1919. Johnsen relinquished his temporary rank of captain on 3 December 1918, and was transferred to the unemployed list of the RAF on 2 January 1919. He resigned his army commission in the 4th London Brigade on 17 November 1920, but retained the rank of captain.
Personal life On 5 February 1916 Johnsen married Ethel May Bowater (1896–1990), the daughter of Major Sir
Frank Henry Bowater, Bt. They had eight children, six boys and two girls. ==Notes==