Certificate Of Formation

Exhibit 3.91 DELAWARE THE FIRST STATE I, HARRIET SMITH WINDSOR, SECRETARY OF STATE OF THE STATE OF DELAWARE,DO HEREBY CERTIFY THE ATTACHED ARE TRUE AND CORRECT COPIES OF ALL DOCUMENTS ONFILE OF "L-3 COMMUNICATIONS VECTOR INTERNATIONAL LLC" AS RECEIVED AND FILED INTHIS OFFICE. THE FOLLOWING DOCUMENTS HAVE BEEN CERTIFIED: CERTIFICATE OF FORMATION, FILED THE FIFTEENTH DAY OF JANUARY, A.D.2003, AT 9:30 O'CLOCK A.M. CERTIFICATE OF AMENDMENT, CHANGING ITS NAME FROM "VECTOR INTERNATIONALAVIATION LLC" TO "L-3 COMMUNICATIONS VECTOR INTERNATIONAL LLC", FILED THEFIFTEENTH DAY OF DECEMBER, A.D. 2003, AT 5:28 O'CLOCK P.M. AND I DO HEREBY FURTHER CERTIFY THAT THE AFORESAID CERTIFICATES ARE THEONLY CERTIFICATES ON RECORD OF THE AFORESAID LIMITED LIABILITY COMPANY. /s/ Harriet Smith Windsor ------------------------------------- Harriet Smith Windsor, Secretary of State3614588 8100H AUTHENTICATION: 2823401030817895 ...