The helicopters used by Navy SEALs in the raid that killed Osama bin Laden were modified Sikorsky Black Hawks using secret stealth technology.

Numerous media organizations including CNN, ABC News and the Army Times reported the Black Hawks had secret stealth features that included noise canceling modifications. Domes above the rotors and devices which lowered the decibel sounds of the motors created the illusion that the helicopter was moving away from the observer, while in fact, it was actually approaching.

Using a special radar-evading variant of the special operations MH-60 Black Hawks, the SEALS were able to land undetected in bin Laden's Abbottabad, Pakistan compound. Residents of Abbottabad -- or the Pakistan military --did not report hearing the helicopters approaching their city.

One of the Stratford, Conn.-made Black Hawks crashed landed in the compound's courtyard. The helicopter was destroyed by SEALs, but parts of the secret craft lay strewed across the courtyard. Photographs taken at the compound showed a large section of the stealth helicopter's remained intact.

The Army Times reported that the Black Hawk's tail boom, tail rotor assembly and horizontal stabilizers did not resemble any officially acknowledged U.S. military airframe. Photos disseminated via the European PressPhoto agency also showed children picking up pieces of composite material that apparently covered the Black Hawk to avoid being detected on radar.

The photos have aviation analysts buzzing over the top secret, never-before-seen stealth-modified helicopters.

If not for the crash, the existence of a stealth Black Hawk would probably remain an exercise in speculation, especially since its existence has been so well protected some analysts declined to comment on the story because there isn't any information on the aircraft.

Paul Jackson, a Sikorsky spokesman, declined to comment on the aircraft. He referred all questions to the Department of Defense. "Regarding any possible accident investigation," Jackson said. "we customarily support the military when requested to do so. We have not received such a request."

Vertical Magazine's story on the helicopter was widely circulated as analysts postulated that radar-evading technology might have added weight to the aircraft and contributed to the hard landing that crippled the craft during the raid.

The Black Hawks on the mission to kill bin Laden, appear to have had a modified exterior akin to the F-117 Night Hawk stealth fighter built by Lockheed Martin.

The F117 emerged during the first Gulf War, and prior to combat msisions, the only people who had any information on it were mostly miners living out in the Southwestern states where the aircraft was tested.

Sikorsky and Lockheed have a long history together and the two share a key Naval Seahawk contract, in which Lockheed receives a basic Seahawk helicpter and upgrades it to fight submarines.

Sikorsky has told trade magazines very little beyond the regular company line that it remains available to its customer to assist in any investigation.

Dan Goure, a former Department of Defense official and vice president of the Lexington Institute, told ABC News the helicopter is like nothing he's ever seen before. "This is a first. You wouldn't know that it was coming right at you. And that's what's important, because these are coming in fast and low, and if they aren't sounding like they're coming right at you, you might not even react until it's too late... That was clearly part of the success."

According to, the stealth helicopter technology evolved from earlier attempts by the U.S. military to develop a similar rotary wing aircraft. A prototype version, the Boeing/Sikorsky RAH-66 Comanche, which was designed as a reconnaissance platform carrying a two-person crew, was canceled during its development in 2004. It was never operational.

Much of that development happened at Sikorsky's Bridgeport, Conn. Comanche plant located in the city's South End. Production of the Comanche would have taken place at Sikorsky's site in Bridgeport. Boeing was to be responsible for manufacturing and assembling the composite tail section and rotor blades and Sikorsky for manufacture of the main fuselage and gearbox and for integration and final assembly of the airframe.

When the $39 billion program was canceled, it lead to hundreds of layoffs at Sikorsky.