Fomicheva was born in Moscow, but spent her entire childhood in Znamenka village. Her father died in a year after her birth and later her elder brother Valentin, who was the primary breadwinner of the family after father's death, also died, so the family suffered severe material hardships. In 1931 after graduating from a 7-year comprehensive school she was hired as a bookkeeper's apprentice while studying in a banking school. Upon graduation she became an accounting associate in the Gosbank. She took pleasure in hiking, mountaineering and other sports. In 1936 Fomicheva joined glider club. Her skills were so good in it that she was invited to participate at the paramilitaryflying club. By 1938 she was qualified as a flight instructor and in 1938-1941 trained young people in a flying club in Reutov.
On 22 June 1941, the first day the Third Reich invaded the USSR, Fomicheva volunteered for the frontline flying service and was accepted by the 122nd Aviation Group - a special women's unit under the command of Marina Raskova. Initially she opted to train as a fighter pilot but Raskova, after examination of her abilities, decided to assign her to the 587th Bombardment Aviation Regiment, intended to operate the Sukhoi Su-2 light bomber. The regiment later received the Guards designation and was renamed the 125th Guards Dive Bomber Regiment. She took her military and tactical training in the Engels Military Flying School in the Saratov Oblast. The unit ended up using Petlyakov Pe-2 bombers instead of Sukhoi Su-2 light bombers. By January 1943, when the 587th first engaged in combat, Fomicheva was a flight commander and the vice-commander of her squadron. Later she took command of the squadron. On 17 September 1943, Fomicheva's aircraft was damaged by enemy flak and her face was wounded by fragments of the cockpit's glazing. Since her navigator was severely wounded and incapable of bailing out, Fomicheva could not leave the aircraft and had to land it on the airfield of a Soviet fighter unit near the frontline. There was an aircraft on the main runway, so she made the landing beside the main runway. When the landing run a wheel of Fomicheva's aircraft got into a bomb crater, the plane nosed-over and caught fire. Fomicheva suffered severe injuries and burns. Airfield personnel helped the crew escape the burning aircraft. By January 1944, Fomicheva recovered from her injuries and resumed flying. On 23 June 1944, in the second sortie of the day, Fomicheva's aircraft was hit by enemy flak when approaching the target, setting the left engine aflame and killing her gunner. Fomicheva herself had her leg severely wounded but continued the mission and dropped the bombs on the target. She then turned the burning aircraft back towards the frontline to avoid capture by the enemy, flying until she got over friendly territory. She bailed out at an altitude of no more than 200 meters, but not before making sure that her navigator Galina Dzhunkovskaya successfully parachuted to safety. Both she and Dzhunkovskaya suffered serious burns. On 15 July 1944, Fomicheva resumed flying. By December, 1944, Fomicheva had flown 55 combat missions with 46,750 kg of bombs dropped. Her subordinates and superiors appreciated her performance as a pilot and as a squadron commander, as she was instrumental in a number of instances in reducing or preventing losses of aircrew. She also was responsible for missions critical for the success of ground forces' operations by destroying valuable enemy assets and targets On 23 December 1944 Fomicheva's command recommended her for the title of the Hero of Soviet Union, which she received on 18 August 1945.
