http://www.armytimes.com/news/2011/05/army-mission-helocopter-was-secret-stealth-black-hawk-050411/ The helicopters that flew the Navy SEALs on the mission to kill Osama bin Laden were a radar-evading variant of the special operations MH-60 Black Hawk, according to a retired special operations aviator. The helicopter’s low-observable technology is similar to that of the F-117 Stealth Fighter the retired special operations aviator said. “It really didn’t look like a traditional Black Hawk,” he said. It had “hard edges, sort of like an … F-117, you know how they have those distinctive edges and angles — that’s what they had on this one.” In addition, “in order to keep the radar cross-section down, you have to do something to treat the windshield,” he said. If a special coating was applied to the windshield it is “very plausible” that would make the helicopter more difficult to fly for pilots wearing night-vision goggles, he said. The helicopters carrying the SEALs arrived over the bin Laden compound at about 1 a.m. Monday local time. One crash-landed in the courtyard and was so badly damaged it was unable to take off again. That crash landing might have been caused by a phenomenon known as “settling with power,” which occurs when a helicopter descends too quickly because its rotors cannot get the lift required from the turbulent air of their own downwash. “It’s hard to settle with power in a Black Hawk, but then again, if they were using one of these [low-observable helicopters], working at max gross weight, it’s certainly plausible that they could have because they would have been flying so heavy,” the retired special operations aviator said, noting that low-observable modifications added “several hundred pounds” to the weight of the MH-60, which already weighs about 500 to 1000 pounds more than a regular UH-60 Black Hawk. The special operations troops on the bin Laden mission destroyed the stricken aircraft — most likely using thermite grenades — but the resultant fire left the helicopter’s tail boom, tail rotor assembly and horizontal stabilizers intact in the compound’s courtyard. Photographs of the wreckage taken the next day raced around the Internet, creating a firestorm of speculation among military aviation enthusiasts because the tail of the helicopter did not resemble any officially acknowledged U.S. military airframe. This was to be expected, the retired special operations aviator said. “Certain parts of the fuselage, the nose and the tail had these various almost like snap-on parts to them that gave it the very unique appearance,” he said. He and another source referred to the disc-shaped device that is seen covering the tail rotor in the photographs as a “hubcap.” If the radar-evading technology worked, it “would be a true statement” to say that the use of the low-observable Black Hawks was evidence that the United States gave Pakistani authorities no advance warning of the mission, the retired special operations aviator added. The low-observable program started with AH-6 Little Bird special operations attack helicopters in the 1980s, said the aviator. During the 1990s U.S. Special Operations Command worked with the Lockheed-Martin Skunk Works division, which also designed the F-117, to refine the radar-evading technology and apply it to the 160th Special Operations Aviation Regiment’s MH-60s, he said. USSOCOM awarded a contract to Boeing to modify several MH-60s to the low-observable design “in the ’99 to 2000 timeframe,” he said. Discuss: The secret stealth Black Hawk Initial plans called for the low-observable Black Hawks to be formed into a new unit commanded by a lieutenant colonel and located at a military facility in Nevada, the retired special operations aviator said. “The intent was always to move it out west where it could be kept in a covered capability,” he said. USSOCOM planned to assign about 35 to 50 personnel to the unit, the retired special operations aviator said. “There were going to be four [low-observable] aircraft, they were going to have a couple of ‘slick’ unmodified Black Hawks, and that was going to be their job was to fly the low-observables.” SOCOM canceled those plans “within the last two years,” but not before at least some of the low-observable helicopters had been delivered to the Nevada facility, the retired aviator said. “I don’t know if it was for money or if it was because the technology was not achieving the reduction in the radar cross-section that they were hoping for,” he said. In the meantime, MH-60 Black Hawk crews from the 160th’s 1st Battalion, headquartered at Fort Campbell, Ky., would rotate to Nevada to train on the stealthy aircraft, he said. The low-observable MH-60s were armed with the same sort of door mini-guns as standard MH-60s, he said. “There was not a DAP conversion,” he added, referring to the MH-60 variant known as the Direct Action Penetrator, which is equipped with stub wings upon which can be fitted a variety of armaments. The early versions of the low-observable Black Hawks were not fitted with air-to-air refueling probes, the retired special operations aviator said. “The probe would disrupt the ability to reduce the radar cross-section,” he added. “There was no way to put some kind of a hub or cowling over the probe that would make it stealthy.” However, he said he did not know whether the models that flew the bin Laden mission had been equipped with such probes. USSOCOM spokesman Army Col. Tim Nye said his command had no comment for this story.