The expected signature of substorm field-aligned currents is described for synchronous satellites near 10 ¿ magnetic latitudes. The main effect is a positive D perturbation premidnight and a negative D perturbation post-midnight. This behavior is illustrated for two substorms near the fall equinox. A second pair of substorms taken from winter solstice do not show the expected behavior. The absence of this effect in winter observations is verified statistically by superposed epoch analysis. A simple explanation of this behavior based on the geometry of the plane of magnetic symmetry is presented. During disturbed times at winter solstice a synchronous satellite nominally at 10 ¿ magnetic latitude is effectively at the magnetic equator. This distortion of the magnetic equator must be considered in future models of the distrubed magnetospheric magnetic field.