Smectic-A helical filaments grown in an isotropic phase have been observed in the binary mixture of octyloxycyanobiphenyl and dodecyl alcohol. The helical structures are made from reeling of the tubules, and are formed by the liquid crystalline molecules without chirality. The temperature sequence has been established for the observation of smectic-A helical filaments. It is found from the observation that the stability of the helical filaments depends essentially on the cooling rate.