 Complement bundle on a complex Stiefel manifold

The orthogonal complements of the universal frames define a complex vector bundle of rank $n-k$ inside the trivial ${\mathbb{C}}^n$ bundle. The orthogonal projector $I-{\sum }_i{v}_i{v}_i^{\ast }$ is smooth of constant rank, giving local bundle frames. Its underlying real bundle has canonical orientation and rank $2(n-k)$. Its sphere bundle is exactly $V_{k+1}({\mathbb{C}}^n)$, by appending the unit vector in the complement to the frame.