The pilot's continued VFR flight into adverse weather, spatial disorientation, and failure to maintain aircraft control. Factors associated with the accident were pressure by the company to continue flights in marginal weather, and the "flat" lighting leading to whiteout conditions. Additional factors were the pilot's lack of instrument experience, lack of total experience, inadequate certification and approval of the operator by the FAA, and the FAA's inadequate surveillance of the emergency instrument procedures in use by the company.