  Accretion powered pulsars exhibit a variety of lightcurves. In this paper we
propose to classify the observed lightcurves as single or double pulsed.We
analyze the lightcurves of 86 accretion powered pulsars and assign them to
these classes. We present three datasets: first in which the classification can
be easily done, second for which the classification is more difficult and not
certain, and third for which we were unable to classify the pulsar because of
lack of published data. We analyze a simple model in which the angles between
the magnetic and rotation axis $\beta$, and between the rotation axis and the
line of sight $\theta$ are random, and show that it is inconsistent with the
data. We also present a model in whichthe angle between the magnetic axis and
rotation axis is restricted and compare it with the data. This leads to an
upper limit on the angle $\beta < 40^\circ$. We conclude that there must be a
mechanism that leads to alignment of the magnetic and spin axis in X-ray
pulsars.
