side wall was remarkable (dramatically shear or rounded). The wash/back-wash of the 

 swell impacting the iceberg was visible as a wake. 



• Size: small. IIP categorizes small icebergs as those with lengths between 15 and 60 m. 



• Watcrlinc length: -30 m (as estimated by the Ice Observer, using binocular reticle and IIP 

 size-estimation chart). Subsequent ship observations of the iceberg reported lengths 

 ranging from 30 to 70 m, which puts the iceberg in the upper range of the small category. 



• Height: -10 m (estimated) 



PHASE 2: NORTH-SOUTH EXPANDING PARALLEL SEARCH 



Once at patrol altitude, four north-south legs were flown at increasing offset from the known 

 iceberg target. The first leg was flown at 15 nm offset, the second at 30 nm, the third at 50 nm, 

 and the fourth at 60 nm. Leg length was planned for -100 nm to allow observation of detection, 

 target return (both on zoomed and whole display), and loss of the target from the radar screen. 

 Once the target was lost, the aircraft proceeded to the waypoint at the start of the next leg. The 

 target was confidently (no false-alarm targets in background) detected at the 15 and 30 nm 

 offsets. The iceberg was detected at 50 nm, but not without zooming on the known position of the 

 target. The target was not detected at 60 nm. The radar range was set at 40 nm for the first two 

 legs and 80 nm for the second. Table 1 summarizes the detection results. 



PHASE 3: EAST-WEST EXPANDING PARELLEL SEARCH 



After Phase 2, the leg orientation shifted to cast-west for Phase 3. The datum offset for Phase 3 

 was similar to Phase 2, with the exception that the 60 nm offset leg was eliminated. The iceberg 

 was confidently detected during the 30 nm and 15 nm offset legs, but not on the 50 nm offset leg. 

 The radar range was set to 80 nm during the 50 nm offset leg and 40 nm for the last two offset 

 legs. Table 1 summarizes the detection results. At the completion of Phase 3, the aircraft returned 

 to the iceberg to mark its final position and time. Table 2 summarizes the target's position and 

 drift throughout the experiment. 



Summary 



• Initial-detection (Phase 1 ) range was excellent, but when evaluating this conclusion, one 

 should also consider the ideal on-scene search conditions, which included good visibility, low 

 sea state, and negligible target density. These ideal conditions arc unusual on the Grand 

 Banks. 



• Phase 2 and Phase 3 detection results are also promising, but must be weighed with the ideal 

 search conditions and the fact that operators were "alerted," that is, the target and its position 

 were know prior to detection. No matter how qualified the experiment's positive results are, 

 however, the high-detection rate (five of five successful detections for ranges similar to 

 normal IIP operations) warrants further investigation. 



• The APN-241 can mark and log targets with user-customized identifiers. Marked targets 

 indicate geographic positions vice actual target position. For example, a target will "drift" 

 from its mark because the radar docs not "track" targets, making subsequent target detection 

 more difficult. In other words, targets observed later in a patrol may have been detected or 

 identified earlier, but an operator may be unable to distinguish immediately between old and 

 new targets. 



• Currently, there is no way to take digital radar data from the aircraft. Ideally, IIP personnel 

 could leave the aircraft with a digital target list or a digital archive of the radar return and 



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