How to get Ultimate Weapon without Hidden Packages PS2

I understand that a lot of people are having trouble finding the Ultimate Weapon
(Appache Helicopter) and the only other way I know how to get it without hidden 
packages is to complete all the missions. If you have done a lot of missions and 
don't have many hidden packages, go ahead and try to finish the whole game.TIP-The 
last mission is when you have to fight off the mafia, then kill Lance because      
he bought you out,then kill Sonny Forrelli(They don't go down easy, so come  
prepared).After you complete all the missions, the Appache appears at the Fort 
Baxter Military Base. IMPORTANT TIP-Go to the police station and get the cop  
uniform in the locker room before getting the helicopter. To get it on foot,bust 
through the entrance, turn left and go up the stairs beside the building, run 
straight to the big building,follow the path beside it until you see stairs     
going to the ground, follow them down keep going straight to the fence, run    
across it until there is a doorway. By this time you should be able to look     
north and see it beside a como tent. Run north until you hit a fence, run east   
along it until you find a doorway, go through it, then run west along the fence 
until you see the helicopter just to the right of you. Get in it (Military people 
won't chase you if you have the cop uniform), and R1 fires the machine gun, and O 
fires rockets.
 
Thank you for reading this, but don't try to copy this because I found it out, not 
you(No offense to anyone else who may have known how to do that)