We report the first measurement of the double-spin asymmetry ALT for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized 3He target. The kinematics focused on the valence quark region, 0.16<x<0.35 with 1.4<Q2<2.7 GeV2. The corresponding neutron ALTasymmetries were extracted from the measured 3 Heasymmetries and proton over 3 He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function gq1T and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for π− production on 3 He and the neutron, while our π+ asymmetries are consistent with zero.