 On 16 April 1942, Fighter Project Officer Benjamin S. Kelsey ordered 500 A-36 Apaches, a redesign that included six .50 in (12.7 mm) M2 Browning machine guns, dive brakes, and the ability to carry two 500 lb (230 kg) bombs.Kelsey would rather have bought more fighters but was willing instead to initiate a higher level of Mustang production at North American by using USAAF funds earmarked for ground-attack aircraft when pursuit aircraft funding had already been allocated.It was the first airframe of the Mustang "family" (Apache, Invader, or Mustang) to be drop-tank capable.