  Recent detection of suborbital gamma-ray variability of Flat Spectrum Radio
Quasar (FSRQ) 3C 279 by Fermi Large Area Telescope (LAT) is in severe conflict
with established models of blazar emission. This paper presents the results of
suborbital analysis of the Fermi/LAT data for the brightest gamma-ray flare of
another FSRQ blazar 3C 454.3 in November 2010 (MJD 55516-22). Gamma-ray light
curves are calculated for characteristic time bin lengths as short as 3 min.
The measured variations of the 0.1-10 GeV photon flux are tested against the
hypothesis of steady intraorbit flux. In addition, the structure function is
calculated for absolute photon flux differences and for their significances.
Significant gamma-ray flux variations are measured only over time scales longer
than ~5h, which is consistent with the standard blazar models.
