Page:Iran Air Flight 655 investigation.djvu/83

 by USS VINCENNES due to the ducting conditions prevalent that day.

8.(U) The CO, "GW" and key CIC AAW operators sincerely believed that they were engaging a hostile aircraft.

9.(U) The range and altitude information passed to the CO on Net 15 was correct until TN 4131 reached approximately 15 NM. Approximate time.

U 10. TN 4133 (Iranian C-130) which departed Bandar Abbas almost simultaneously with missile launch was squawking Mode I-11 and could have been a potential source of confusion between Mode I-11 and Mode II-1100 on IDS and AAWC's RCI.

11.(U) In the excitement of the impending engagement, it is entirely possible that reports of decreasing altitude passed over the net by TIC after the 15 NM point could have occurred if TIC passed only values, which were interpreted as altitude, or he simply mis-read his CRO and interchanged altitude and range.

12.(U) The ship's air controller supervisor's recollection of 7800 ft altitude at 6 NM was actually the altitude of TN 4131 33 seconds after missile intercept. In other words, the plane's altitude as it was plummeting to the water.

13.(U) Recollection of Mode III IFF responses other than 6760 for TN 4131 were caused by imperfect recall by the IDS, ACS, AAWC, SSES, console operators in CIC, as well as the post incident SITREP writer.

14.(U) The violent maneuvers of the ship, the noise of the guns firing, gear falling in CIC and the lights in the LSD's flickering, heightened the tension in CIC during the critical time TN 4131 was being evaluated.

U 15. Except for Mode IV, IFF codes are not absolute determinators for engagement. Mode III is the least reliable because all aircraft are capable of squawking Mode III.

U 16. AN/SLQ-32 Set-up in USS VINCENNES/SIDES/MONTGOMERY were adequate to intercept a COMMAIR radar. The position and nose attitude of Flight 655 precluded AN/SLQ-32 from intercepting/displaying IR 655's radar--if it was in fact transmitting.

17.(U) There were no Link-11 dual designations (two separate vehicular tracks with the same LINK-11 STN) of TN 4131 during the period of interest. Therefore, a LINK-11 track crossover problem did not occur.