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We present an analysis of off-limb cool flare loops observed by SDO/AIAduring the gradual phase of SOL2017-09-10T16:06 X8.2-class flare. In the EUVchannels starting from the 335 {\AA} one, cool loops appear as dark structuresagainst the bright loop arcade. These dark structures were precisely coaligned(spatially and temporally) with loops observed by SST in emission lines ofhydrogen and ionized calcium. Recently published semi-empirical model of coolloops based on SST observations serves us to predict the level of hydrogen andhelium recombination continua. The continua were synthesized using anapproximate non-LTE approach and theoretical spectra were then transformed toAIA signals. Comparison with signals detected inside the dark loops shows thatonly in AIA 211 {\AA} channel the computed level of recombination continua isconsistent with observations for some models, while in all other channels whichare more distant from the continua edges the synthetic continuum is far toolow. In analogy with on-disk observations of flares we interpret the surplusemission as due to numerous EUV lines emitted from hot but faint loops in frontof the cool ones. Finally we briefly comment on failure of the standardabsorption model when used for analysis of the dark-loop brightness.

Signatures of Helium continuum in cool flare loops observed by SDO/AIA