The tail rotor gearbox and the intermediate gearbox are capable of taking a 23mm hit and keep on ticking. The gearboxes are not lubricated with conventional oil but very viscous non-hydrocarbon grease. The helicopter should be able to fly for thirty minutes providing the gear mesh was not destroyed or impaired when hit by the 23mm round. If a tail rotor blade is hit it should be able to survive as can the main rotor blades. This is due to their construction. The main trannie can also survive a direct hit and operate for thirty minutes even though the oil had drained out. Inside of each gear set is an absorbent material that retains oil so when the gear case is compromised and the oil runs out the oil retained in the respective gear sets is forced out by of all things, centrifugal force into the gear mesh. However if a tail rotor blade is lost due to a direct hit then all is lost and the pilot if he can should immediately set it down on the ground.