No, the composition of two bundle projections needn't be a bundle projection. It is already not true that the composition of two covering maps is a covering map. You can find a counterexample in Spanier's classic [*Algebraic Topology*][1], Chapter 2, §2, Example 8, page 69. Another counterexample, based (!) on the notorious Hawaiian ring space is given by Jerzac's very nice,detailed paper [here][2]. However, on the positive side, the composition $g\circ f :X\to Z$ of the covering maps $f:X\to Y$ and $g:Y\to Z$ *is* a covering map in each of the following two cases: a) The covering $g$ is finite (= has finite fibers) b) The space $Z$ has a universal covering (for connected $Z$, this means that $Z$ is locally pathwise connected and semi-locally simply connected). [1]:http://books.google.fr/books?id=h-wc3TnZMCcC&printsec=frontcover&dq=spanier+algebraic+topology&hl=fr&ei=_15lTp61C8Pj4QTU0vDHCg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCsQ6AEwAA#v=onepage&q&f=false [2]:http://www.math.uchicago.edu/~may/VIGRE/VIGRE2008/REUPapers/Jerzak.pdf