Story related, cannot be missed. Fight is after the third Weapon X facility section. Tips on defeating David Nord: you will not directly fight David Nord, however, he can make your life really difficult. After defeating the four W.E.N.D.I.G.0 Prototypes on the roof top lunge towards the first helicopter (press
to lock on and
to lunge). Set the engine on fire and evade the shotgun bursts. Smash the glass of the window and pull out the pilot. Freefall to the next chopper and land on near its tail rotor. Use
to cut off the tail of the helicopter and freefall to the next chopper. Again, land near the tail rotor and then start tapping
like crazy to destroy the rotor and make the chopper crash.