  We measure the LyC escape fraction in 54 faint Lyman Alpha Emitters (LAEs) at
$z\simeq3.1$ in the GOODS-South field. With the average magnitude of $R=26.7$
AB ($M_{UV}=-18.8$, $L\simeq0.1L^*$), these galaxies represent a population of
compact young dwarf galaxies. Their properties are likely to resemble those in
the galaxies responsible for reionising the Universe at $z>6$. We do not detect
LyC emission in any individual LAEs in the deep {\em HST} F336W images, which
covers the rest-frame 820\r{A}. We do not detect the LyC emission of these LAEs
in the stacked F336W images, either. The $3\sigma$ upper limit of LyC escape
fractions is $f_{\rm esc}<14-32\%$. However, the high Ly$\alpha$ rest-frame
equivalent width, low stellar mass and UV luminosity of these LAEs suggest that
they should have $f_{\rm esc}>50\%$. The low LyC escape fraction from this work
and other stacking analysis suggest that the LyC leaking galaxies with $f_{\rm
esc} > 50\%$ at $z=2-3$ do not follow the relation between the $f_{\rm esc}$
and UV luminosity and Ly$\alpha$ equivalent width (EW) derived from typical
galaxies at similar redshift. Therefore, the UV luminosity and Ly$\alpha$
equivalent width (EW) are not the best indicators for the LyC escape fraction.
