Hide the Navigation Bar totally, but it still exists if the Sub screens needs it.

gistfile1.m

// Hide Navigation Bar
    [self.navigationController.navigationBar setBackgroundImage:[UIImage new]
                                                  forBarMetrics:UIBarMetricsDefault];
    self.navigationController.navigationBar.shadowImage = [UIImage new];
    self.navigationController.navigationBar.translucent = YES;
    self.navigationController.view.backgroundColor = [UIColor clearColor];