The Tainan Kokutai was redesignated the 251st Kokutai on November 1, 1942.
In May of that year they received two J1N1 Gekko (Irving) night fighters armed with upward and downward firing 20mm cannons. Flying from Lakunai Airfield near Rabaul, Ono became the second Gekko pilot at Rabaul, flying with Shigetoshi Kudo.
June 10, 1943
Ono took off with Lt. (jg) Kisaku Hamano as observer to intercept 20 bombers attacking Rabaul, this was the second time that J1N1 Gekkos were used as night fighters. Attacked a B-17 caught in search lights at 4:02am a 7,000' and attacked from 1,500' below opening fire at 4:04 and observed hits of his 20mm cannons in the left wing. The bomber lost altitude and disappeared into the darkness at 2,000' about eight minutes after the attack. At 4:48 Ono spotted a second bomber in searchlights and attacked it, 20 minutes later. He finally hit the bomber in the right wing and saw it catch fire, but the flames were extinguished and it disappeared into the night. Japanese claimed one bomber destroyed and on probable this night.
On the American side, 43rd BG lost no bombers that night, but one radio operator from 63rd BS was injured by gunfire from a night fighter.
June 13, 1943
Took off with Hamano as observer at 02:40am, followed three minutes later by J1N1 piloted by Kudo/Sugawara. Ono could find no enemy aircraft and landed at 05:40am.
Claims in J1N1
1 x B-17 (June 13, 1943) * in fact, not lost
Probable B-17 (June 13, 1943) *
in fact, not lost
June 17, 1943
Took off from Ballale as observer with Okado as pilot. Shot down PB4Y 31952.
References
Moonlight Interceptor covers page 38 - 39
Naval Night Fighters by Yoji Watanabe 28 - 45
Thanks to Henry Sakaida, Edward Rogers for additional information
