self.navigationController value gets null in Tabbar VIew

I have a navigation controller as the root view c开发者_高级运维ontroller. I have a UIView then a UITableView, then again a UITableView, then a TabbarView and each of my tabbarview is a hierarchy of views. Now my problem is that I am able to get the value of self.navigationcontroller till the last UITableView but the value gets null in the TabbarView. Now is there a way I can access the value in the Tabbarview. Do I have to create a new navigation controller for each tabs in the tabbarview and then assign the root navigation controller value to it?

My below code does not work, The last controller where I can get the value of the navigationController is AssignmentViewController.

Code from AssignmentViewController:

- (void)viewDidLoad {

UITransTabViewController *transtvController = [[UITransTabViewController alloc] initWithNibName:@"TransTabViewController" bundle:nil];


    self.transtabViewController = transtvController;        
    transtvController.naviController=self.navigationController;
    [transtvController release];
}

In my UITranTabViewController.h I have the below code,

@interface UITransTabViewController : UIViewController <UITabBarDelegate> {
        NSArray *viewControllers;
        IBOutlet UITabBar *tabBar;
        IBOutlet UITabBarItem *arrivalsTabBarItem;
        IBOutlet UITabBarItem *departuresTabBarItem;
        UIViewController *selectedViewController;   

    UINavigationController *naviController;
}

    @property (nonatomic, retain) NSArray *viewControllers;
    @property (nonatomic, retain) IBOutlet UITabBar *tabBar;
    @property (nonatomic, retain) IBOutlet UITabBarItem *arrivalsTabBarItem;
    @property (nonatomic, retain) IBOutlet UITabBarItem *departuresTabBarItem;
    @property (nonatomic, retain) UIViewController *selectedViewController;

@property (nonatomic, retain) IBOutlet UINavigationController *naviController;

I am trying to set the value of naviController from the AssignmentViewController, but still I get the

NSLog(@"MY NAV CONTROLLER IN TRANSTABVIEWCONTROLLER IS = %@", self.naviController);

value as NULL.