9: Not So Fast - Grand Theft Auto 4: The Ballad of Gay Tony
It's time to grab those diamonds. After the cutscene, grab a car and make your way to Yusuf's helipad in Westminster. There, get in the ridiculously extravagant Buzzard and fly to the Libertonian in Middle Park. Land the Buzzard on top of the museum and get out. Walk over to the scaffolding on the southwest side of the building and drop down to the window to overlook the deal.
With the diamonds in hand, approach the ladder, press the Y button, and hold the A button to quickly climb up. Once back on the roof, immediately get in the Buzzard and take off. Before you can escape the authorities you must shoot down three police helicopters. The helicopters are marked on your radar.
Fight the enemy helicopters high above the city.
The weaponry attached to the Buzzard cannot lock-on to targets, so downing the choppers will require some finesse at the controls. It's best to fly a bit above a target, and then push the Right Stick up to tilt the front of the Buzzard toward it, tapping the X button to let off some missiles. With any luck, one of the missiles will hit and destroy the helicopter.
You might find it easier to shoot down the helicopters with the camera set to first-person. To switch to the first-person camera view, press the Back to cycle through until the camera is set. A word of warning: If you suffer from any degree of motion sickness, stick to the third-person view.
Missiles fired by enemy helicopters are homing, but they can be dodged. The Buzzard can take a direct hit and come off seemingly unscathed, but try to dodge incoming missiles regardless.
When the first helicopter has been destroyed, two more will appear. Shoot them both down, fly the Buzzard back to the helipad in Westminster and land it to complete the mission.
Player Damage: 20%
Helicopter Damage: 80%