Forty-seven Sixth ships were airborne by 1840 that day, but engine trouble forced two to return to base shortly after takeoff. The remaining forty-five, except one which bombed a target of opportunity, hit Nagaoka at 0100 with excellent results. The last crews over the target reported smoke and thermals rising from the burning city to a height of 20,000 feet. Later photographs showed 2.03 sq mi, 65 per cent of the city burned out. Opposition from the Japs was negligible as only six night fighters were seen. The Group’s contribution to the Air Force Day raid was forty-five planes over the Empire, its greatest number thus far.
[Pirate’s Log, pp. 52-53]