EXHIBIT 12.4 WEST TEXAS UTILITIES COMPANY RATIO OF EARNINGS TO FIXED CHARGES FOR THE TWELVE MONTHS ENDED MARCH 31,1999 (Thousands Except Ratio) (Unaudited) Operating Income $ 58,595 Adjustments Income taxes 26,490 Provision for deferred income taxes (6,111) Deferred investment tax credits (1,510) Other income and deductions 1,184 Allowance for borrowed and equity funds used during construction 1,342 ----------- Earnings 79,990 =========== Fixed Charges: Interest on long-term debt 20,352 Interest on short-term debt and other 4,738 ----------- Fixed Charges 25,090 =========== Ratio of Earnings to Fixed Charges 3.19 ===========