  We consider a motorized aircraft tethered to a central anchorage point in a
configuration similar to a control line model airplane. For this system, we
address the problem of automatic take-off and landing (ATOL) with a circular
path, whose center and radius are defined by the anchorage point and the tether
length, respectively. We propose a hierarchical control architecture for ATOL
and discuss the controllers designed for each control layer and for each of the
flight phases. Simulation results are reported, showing the viability of the
approach, but also showing the limitations on the maximum altitude attainable
with a fixed-tether length. The tethered aircraft and the proposed ATOL control
architecture are to be used in an Airborne Wind Energy System.
