Jan Eugeniusz Ludwik Zumbach (14 April 1915, Ursynów, Congress Poland, Russian Empire – 3 January 1986, France) was a Polish-Swiss[1] fighter pilot who became an ace and squadron commander during the Second World War.

During the Cold War, he became a mercenary in Africa and played a key role in forming the air forces of the breakaway states of Katanga and Biafra.

The son of Eugeniusz Zumbach and Halina née Gorzechowska from a family of landowners[2] hailing from the region of Płock.

All three aircraft carried a cartoon of Donald Duck on the port side of the fuselage, slightly forward of the cockpit.

On 25 September 1944, he scored his final victory of the war, a probable kill over a JG 26 Fw 190 over Arnhem.

While flying an Auster that was used to visit units under the Group's command, he made a navigational error and ran out of fuel.

He went on to deal in second-hand aircraft before again becoming a mercenary in 1967, as he organised and commanded the air force of Biafra, flying the B-26 Invader, using the nom de guerre of John Brown.

[10] During that time, he also partook in Biafran air force raids, including killing a Nigerian army chief of staff during an attack on Markudi airfield he led.

Zumbach died in unclear circumstances on 3 January 1986 in France, and was buried at Powązki Military Cemetery in Warsaw, Poland.