An amended return to claim a refund generally can be filed up to three years from the due date of that return (or the actual filing date if after the due date).
A statutory method of depreciation allowing accelerated rates for most types of property used in business and income-producing activities during the years 1981 through 1986. It has been superseded by the modified accelerated cost recovery system (MACRS) for assets placed in service after 1986.