We report on time-of-flight (TOF) hole mobility measurements in an aged discotic columnar liquid crystal, Hexakis(pentyloxy)triphenylene (HAT5). The experimental data was fit to an interfacial trapping model based on Van de Walle’s approximations. The theory accurately reproduces the TOF transients of delayed charge release near the optically excited material/electrode interface. Interfacial trapping appears only in the aged materials, but the bulk mobility is the same as that of the pristine material. We also discuss preliminary results of TOF photocurrent transients of HAT5 exposed to ozone.