I have often wondered whether the U.S. had a “black” program to provide a stealthy air vehicle to transport special forces into sensitive locations. It seems an obvious requirement, yet very little has surfaced about such a capability. 

Of course, the conventional aircraft and helicopters of U.S. Special Operations Command (SOCOM) are equipped with all sorts of systems to enable covert insertions...terrain-following radars, infrared navigation devices, high-altitude low-extraction paradrops and so on. And low observability can be as much about tactics, techniques and procedures as about technology.

Regarding helicopters in particular, reducing the acoustic signature is probably just as important as evading radars or infrared-detection systems. Much work has already been done in this field, for everyday civilian use as well as covert military applications. Way back in 1971, a Hughes OH-6A light observation helicopter was extensively modified by adding an extra main rotor blade, making changes to the blade tips, providing mufflers for the air intake and exhaust and providing the pilot with a control to slow the main rotor speed when required. Dubbed “The Quiet One,” this helicopter flew into North Vietnam from Laos so that a wiretap could be placed on a key telephone line.

The Osama bin Laden raid into Pakistan suggests that radar-evading stealth technology has finally been applied to this operational problem. It’s not yet clear whether an all-new helicopter has been developed or (more likely) a few of the MH-60 Black Hawks SOCOM uses have been modified.

A classic dilemma for “black” programs is when to “surface” them. SOCOM probably hoped to keep its new capability secret in the Bin Laden raid. That plan foundered when one of the helicopters was disabled at bin Laden’s compound, perhaps by defending fire, perhaps by a hard landing (higher-than-expected temperatures at the site have been reported, which could have significantly degraded hover performance and increased the even-more-serious possibility of a phenomenon known as “settling with power”).

The raiding party subsequently failed to destroy all the evidence, and now the aviation world is speculating about that disc-covered tail rotor and (maybe) all-composite rear structure.

Pakistani troops secured the wreckage and later removed it. Two interesting questions: will it be returned to the U.S.? Or will Pakistan hand it to China, its closest partner in the aerospace industry?