One of the major problems with the original AI radars was that the transmissions spread out over the entire front hemisphere of the aircraft. Shorter wavelengths, like those used in AI, tended to scatter from the ground, sending a portion of the signal back towards the aircraft, the "ground reflection" or "ground return". For the simple reason that the ground is much larger than a target aircraft, the scattered signal overwhelmed any target return, and made it impossible to see any target further away than the aircraft's current altitude. For the supply mission, which was carried out at very low altitudes, this was clearly not going to work.