EXHIBIT 12 L-3 COMMUNICATIONS CORPORATION COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES (IN THOUSANDS, EXCEPT FOR RATIO DATA) PRO FORMA ---------------------------------------------- NINE MONTHS NINE MONTHS YEAR NINE MONTHS ENDED ENDED ENDED ENDED SEPTEMBER 30, SEPTEMBER 30, DECEMBER 31, SEPTEMBER 30, 1998 1997 1997 1998 --------------- --------------- -------------- -------------- Earnings: Income before income taxes ............... $ 25,200 $ 4,300 $ 22,200 $ 30,676 Add: Interest expense ....................... 44,800 44,800 59,800 35,230 Amortization of debt expense ........... 2,790 2,790 3,720 1,805 Interest component of rent expense ..... 5,058 4,832 6,240 4,322 -------- -------- -------- -------- Earnings ................................. $ 77,848 $ 56,722 $ 91,960 $ 72,033 ======== ======== ======== ======== Fixed Charges: Interest expense ....................... $ 44,800 $ 44,800 $ 59,800 $ 35,230 Amortization of debt expense ........... 2,790 2,790 3,720 1,805 Interest component of rent expense ..... 5,058 4,832 6,240 4,322 -------- -------- -------- -------- Fixed Charges ............................ $ 52,648 $ 52,422 $ 69,760 $ 41,357 ======== ======== ======== ======== Ratio of earnings to fixed charges ........ 1.5x 1.1x 1.3x 1.7x ======== ======== ======== ========