US Air Force, Navy Enhance Aircraft Defensibility Models. In April, the U.S. Air Force  conducted tests  to confirm earlier aircraft defensibility models and to gather additional data to provide next-generation countermeasures to improve the aircraft's defensive capabilities. A C-17  was used. While most test details are classified, it was revealed that the aircraft was flown with unusual precision, making flight attitude adjustments in one-degree increments so as to provide ground radar with a complete three-dimensional picture of the C-17.  Data was collected in three different, normal configurations-- clean, personnel airdrop, and cargo airdrop -- to try to obtain minimum and maximum returns. The C-17s radar cross section (RCS) data gathered will be used to refine analyses conducted over the years. The measurements on these particular tests were not made to measure particular C-17 survivability, but rather, with best measurement practices to obtain best valid data. In fact, the tests did validate two types of testing in use, including both software simulations and use of scaled models of the aircraft. 

The vulnerability of large, low-flying aircraft to enemy fire has been known for some time. During the Vietnam War, several P-3 Orion surveillance aircraft of the US Navy, flying at low levels on shipping recon patrols, were downed by enemy fire, with all hands lost. Current US Navy P-3C AIP aircraft carry the AN/AAR-47 Missile Warning System and AN/ALE-47 Countermeasures Dispensing System [CMDS].

Since the beginning of the war in Iraq, US transport aircraft have been used to their maximum capacity and in areas and situations hotter than what had been the case or what had been foreseen when the aircraft were designed. Shoulder-fired MANPADS missiles and even low-tech weapons like rocket propelled grenades have proven a far greater threat than had been envisioned in todays tactical environment in which these aircraft must land, takeoff, and maneuver in close proximity to hostile forces. There already have been several instances in which US transport aircraft have been hit by enemy fire taken from terrorist and insurgent forces operating in small groups in hostile terrain. 

Although the Air Force spokesman also noted that there are no planned similar tests at this time for other aircraft, the co-sponsorship of these tests with the US Navy strongly suggests that there will indeed be both further testing of aircraft. The Navy currently operates the C-130, C-2, C-9, and C-40 transport aircraft, and future logistic supply airplanes such as the Common Support Aircraft (tentatively to replace carrier-based C-2 and S-3 logistic aircraft and perhaps also the E-2C airborne warning and control airplane) will certainly require enhanced protection. K.B. Sherman