An aircraft drive shaft including an outer shaft having a first diameter configured to couple a first gearbox and a second gearbox to provide power transfer between the two gearboxes, an inner shaft concentric with the outer shaft and having a second diameter configured to provide structural support to the outer shaft, a gap defined between an outer peripheral surface of the inner shaft and an inner peripheral surface of the outer shaft, wherein the gap is sized according to a ballistic projectile cross-section size that the aircraft is considered to encounter on an upcoming mission, and a sleeve located at least at first end of the outer shaft connecting the outer shaft to the inner shaft.