EXHIBIT 12.4 WEST TEXAS UTILITIES COMPANY RATIO OF EARNINGS TO FIXED CHARGES FOR THE TWELVE MONTHS ENDED MARCH 31, 1998 (Thousands Except Ratio) (Unaudited) Operating Income $44,751 Adjustments: Income taxes 15,087 Provision for deferred income taxes (4,189) Deferred investment tax credits (1,321) Other income and deductions 2,057 Allowance for borrowed and equity funds used during construction 836 -------- Earnings $57,221 ======== Fixed Charges: Interest on long-term debt $20,352 Interest on short-term debt and other 4,600 -------- Fixed Charges $24,952 ======== Ratio of Earnings to Fixed Charges 2.29 ========