In the SCP Foundation story "Over/",1 the protagonist and his fiancée get kidnapped by some terrorists looking for information, who eventually throw the two of them out of a CH-148 (with parachutes, fortunately). Immediately after the two exit, a mirror monster linked to the protagonist causes the copter to roll hard over; as the helicopter rolls towards inverted, one of the terrorists loses her grip and is finely minced by passage through the main rotor. Protagonist and fiancée land safely, and the fiancée says that they'll need to run, because the remaining terrorists had managed to land the helicopter nearby.
I would not have expected a helicopter (CH-148 or otherwise) that'd taken an adult human through the main rotor while rolling through inverted to be capable of landing successfully, for a number of reasons:
- Helicopter-main-rotor blades do not tend to react well to large, heavy objects passing through them, and chopping up an entire adult human would probably do some pretty nasty damage to the blades.
- Helicopter main rotors are also fairly intolerant of mass imbalances resulting from blade damage; even a fairly-small section of one blade missing can result in an immediate loss of control of both the main rotor and the helicopter itself (often followed within seconds by the unbalanced main rotor tearing itself free of the helicopter altogether).
- Finally, rolling rapidly through inverted would put all sorts of new and interesting forces on the main-rotor assembly in directions it was never designed to have force applied to it in (especially if, as seems to have been the case here, positive G was not maintained through the roll), potentially causing the main-rotor blades to strike the fuselage or the main-rotor mast to strike the adjacent structure2 (either of which would result in loss of control and main-rotor separation, not necessarily in that order) and certainly exacerbating the blade damage from an adult human going through the main rotor.
- As just one example of this, in order for someone who loses her grip on the helicopter to pass through the main rotor, the main-rotor blades on that side of the helicopter would have to have a downward-pointing (in the chopper's frame of reference) lift vector (if the terrorist loses her grip while the main rotor is above her, then that side of the rotor has to accelerate downwards faster than the freefalling soon-to-be-mincee in order to catch up with her, necessitating that it be generating lift in the downwards direction; if she comes loose while the main rotor is under her, that side of the main rotor has to accelerate downwards slower than she does, requiring that it be generating lift in the upwards direction, which, as the main rotor being below its meal corresponds to the helicopter being inverted, requires that it be generating lift in the downwards direction from the helicopter's point of view). This, like any other situation involving a helicopter's main rotor generating downwards-in-the-helicopter's-frame-of-reference lift, would cause the main-rotor blades on that side of the helicopter to cone downwards, towards the rest of the helicopter, and potentially collide with other helicopter structure.
Is it realistic that an S-92-family helicopter - or, for that matter, any helicopter - could (assuming no anomalous augmentations to the helicopter) roll hard through inverted, taking an adult human through the main rotor in the process, and still recover from the upset and make a safe emergency landing?
1: Not a typo.
2: While the S-92 family uses a fully-articulated main rotor, which is not normally susceptible to mast bumping, the extreme lateral forces that would be generated by a rotor disk tilted sufficiently to produce the roll rates involved in this situation might still damage the mast of even a fully-articulated main rotor, and mast bumping would still be an issue for many other types of helicopter in this sort of scenario.