Time evolution of EUV flux of AIA 171 and 94 Å passbands. These fluxes are normalized by the mean magnetic flux (Φ) of photospheric polarities to suppress enhanced trend due to the emerging magnetic flux and by a constant scaling factor (arbitary units). Vertical dotted line indicates the time when the AR is positioned at the central meridian and the solid vertical line refers to the sign reversal time of the photospheric helicity flux (Fig. 7a).