Exhibit 10.58 SUPPLEMENTAL INDENTURE TO BE DELIVERED BY GUARANTORS SUPPLEMENTAL INDENTURE (this "Supplemental Indenture"), dated as of May 5, 2003, among AMI Instruments, Inc., an Oklahoma corporation, Apcom, Inc., a Maryland corporation, Broadcast...Supplemental Indenture • May 13th, 2003 • L 3 Communications Holdings Inc • Radio & tv broadcasting & communications equipment • New York
