might suggest that the NS is orbiting the Be companion in an inclined orbit crossing twice the Be disk plane and giving rise to two outbursts per orbit. Two flares per orbit also observed in 4U1907+097 [@Mak84] and in GRO J2058+42 [@Wil98]. Be transient pulsars also display long-term X-ray variability with typical times about months, consisting of low and high-activity X-ray states. By this the type 1 outbursts are only seen during bright states [@Bay02].

Nevertheless moderate and pulsating X-ray flux was detected at various orbital phases of Be transient binary systems, from A0535+26, for example [@Mot91; @Stee98]. In the RXTE-PCA observations this source was detected at a much lower luminosity of $(2.0-4.5)\cdot10^{33}$ erg/s at which so-called propeller effect is expected. It means that accretion onto the NS surface is inhibited by the centrifugal action of the rotating magnetosphere. Thus the X-ray luminosity that was still detected in this regime can be ascribed to material leaking through the magnetosphere or thermal emission from the heated core of the NS [@Neg00]. The BeppoSax-NFI observations of A0535+262 in quiescence show that X-ray pulsations are still present for luminosity as low as $2.0\cdot10^{33}$ erg/s, but they have not been detected at lower luminosity 