The gyroscopic stablizer bar on the top of the UH-1 rotor system is a key component in balance of the forces exerted on the controls. If something causes this to bind, the control response becomes disrupted and when trying to land that's a pretty bad time to get a flight control malfunction. Be it known that crossbow arrows fired from below into the belly of UH-1's caused deaths and injuries to crewmen and disabled flight control linkages ( in the belly) to the point the aircraft either made emergency putdowns or crashed. They also punctured fuel bladders and caused fuel emergencies. The fuel bladders were manufactured to a standard of self sealing after a hot small arms round penetrated the bladder, not a crossbow stuck in them and maintaining an opening.
Cheif Snake