Having worked with the Air Force special operations tiltrotor program (CV-22) I was surprised to hear helicopters were used in the raid on Osama bin Laden's compound. After all, the Desert One failure was a major impetus for the special operations world to obtain the CV-22. Unlike a helicopter, the CV-22's rotors can tilt perpendicular to the ground in flight to act as propellors allowing the aircraft to fly like a turboprop airplane. With CV-22s the Desert One raid could have been covered in one period of darkness, instead the slow speed and distance meant three periods of darkness would be required - two nights spent in the "empty" desert for ingress and egress with the second night used for the rescue.

Initial news reports stated MH-60s (special ops version of Blackhawks) were used. CV-22s would be far superior to Blackhawks so I wondered why the CV-22 wasn't used. I got part of an answer having just seen a photo of the tail section of the crashed helicoptor left next to the compound. It is not a Blackhawk in fact, I've never seen a helicopter like this. The features have definately been designed for stealth. Additionally, the pile of ash purported to be the rest of the helicoptor is consistent with a burned aircraft built mainly from carbon composite structure. The tail structure reminds me somewhat of the cancelled Army Comanche. Looks like the special ops have opted to use stealth over speed to make their approach into Pakistan.

I found this post by Bill Sweetman at Aviation Week with related commentary and photos.