  We report multi-wavelength (IR-O, UV, X-ray, gamma-ray) data of the flat
spectrum radio quasar (FSRQ) PKS B1424-418 (z=1.52) gathered during an active
phase in 2013 April . As for a few other cases of FSRQs reported in literature,
the detection by the Large Area Telescope onboard Fermi of gamma rays with
energy above 10 GeV indicates that the emission likely occurs beyond the highly
opaque (tau ~10) broad line region. This conclusion is strengthened by a model
fit to the spectral energy distribution, which allows us to locate the emission
region even beyond the distance generally assumed for the dusty torus. The
consequent large size (~1 pc) inferred for the emission region cannot account
for the observed daily-scale variability of the gamma-ray flux. We discuss the
possibility that short-term variability results from fast magnetic reconnection
events, as proposed in recent works.
