Colloquially known as the "Ninak" (from the phonetic alphabet treatment of designation "nine-A"), it served on in large numbers for the Royal Air Force following the end of the war, both at home and overseas, where it was used for colonial policing in the Middle East, finally being retired in 1931.

[2] The prototype proved successful, with the first Liberty-engined DH.9A flying on 19 April 1918, and deliveries to the Royal Air Force starting in June.

As it was decided that the DH.9A would be a standard type in the postwar RAF, the majority of outstanding orders were fulfilled, with 1,730 being built under the wartime contracts before production ceased in 1919.

In 1921, test pilot Lt. Harold R. Harris made the world's first high-altitude flight in a pressurised aircraft in the USD-9A at McCook Field in Dayton, Ohio.

[3] Despite the superior performance of the DH.9A over the DH.9, the DH.9A squadrons suffered high losses during their long range bombing missions over Germany.

The United States Marine Corps Northern Bombing Group received at least 53 DH-9As, and commenced operations in September 1918.

[11] The DH.9A was one of the key weapons used by Britain to manage the territories that were in its control following the collapse of the Ottoman Empire following the Great War.

Five squadrons of DH.9As served in the Middle East,[12] occasionally carrying out bombing raids against rebellious tribesmen and villages.

Despite this the aircraft served successfully, with the Liberty engine being picked out for particular praise for its reliability ("as good as any Rolls Royce") in such harsh conditions.

At home, the DH.9A continued on in regular RAF service until 1930, also forming the initial equipment of the Royal Auxiliary Air Force (RAuxAF).

[14] A single example, serial number F1010, survives and is on display at the Royal Air Force Museum London.

The squadron began flying bombing missions in September 1918, and on the 25th, the crew of F1010 claimed the destruction of a German Fokker D.VII fighter.

The aircraft's fourth and final combat mission was on 5 October when either flak damage or engine trouble forced a landing behind German lines.