Background Iran_Air_Flight_655

the ticonderoga-class cruiser uss vincennes had been deployed persian gulf @ short notice advanced aegis combat system used compensate lack of awacs cover.

in 1984, war between iraq , iran had expanded include air attacks against oil tankers , merchant shipping of neighboring countries, of whom providing aid iraq shipping iraqi oil. flight 655 incident occurred year after iraqi air force attack on u.s. navy guided-missile frigate uss stark on 17 may 1987, killed 37 american sailors. u.s. naval forces had exchanged gunfire iranian gunboats in late 1987, , u.s. navy guided-missile frigate uss samuel b. roberts had struck iranian sea mine in april 1988. 2 months before incident had engaged in operation praying mantis, resulting in sinking of iranian frigate sahand. tensions therefore high in strait of hormuz @ time of incident flight 655.

in response pattern of attacks on shipping, joint chiefs of staff issued notam on 8 september 1987 warning persian gulf countries civilian aircraft must monitor 121.5 mhz vhf aka international air distress [iad] frequency, or 234.0 mhz uhf aka military air distress [mad] frequency, , prepared identify navy ships , state intentions.

on 29 april 1988, u.s. expanded scope of navy s protection friendly neutral shipping in persian gulf outside declared exclusion zones, setting stage shoot-down incident. @ same time, uss vincennes rushed area on short-notice deployment, result of high-level decisions, compensate lack of awacs coverage, hampering u.s. monitoring of southern persian gulf. vincennes, fitted then-new aegis combat system , under command of captain william c. rogers iii, departed san diego on 25 april 1988 , arrived in bahrain on 29 may 1988.

as strait of hormuz @ narrowest 21 nautical miles (39 km) wide, in order traverse strait, ships must stay within sea lanes pass through territorial waters of iran , oman under transit passage provisions of customary law of sea. therefore normal ships, including warships, entering or leaving persian gulf transit iranian territorial waters. during iran–iraq war iranian forces boarded , inspected neutral cargo ships in strait of hormuz in search of contraband destined iraq. while legal under international law, these inspections added tensions in area.