P2V aircraft swept the forecast fallout sector, using visual sightings and search radar out to 800 nmi (1,482 km) on D-2, out to 600 nmi (1,111 km) on D-1, and, if necessary, in front of the cloud on D-day. Since the reliable range of the P2V search radar was taken as 30 to 50 nmi km), nmi (56 to 93 the effective round-trip sweep width of a single P2V was 120 to 200 (222 to 370 km). The P2V aircraft crews were instructed to report Shipping sighted in the D-2 sweeps and to attempt to divert ships sighted on D-1 and D-day. The area involved was huge, and a single (or even two or more) craft could search only a small portion of it. air- The search plan was modi- fied after BRAVO to search Area Green intensively with three P2V aircraft on D-1l, and to make a parallel search with two P2V aircraft out to 600 nmi (1,111 km) with a 240-nmi (444-km) direction of significant fallout. sweep width centered on the forecast This procedure was expected to con- centrate the search effort in the areas where the maximum fallout would occur. The capability was also maintained, and used on some shots, to search on D-day in advance of the cloud. Another danger area defined for the one shot at, Enewetak, NECTAR, (Evelyn) was to avoid excessive drain on aircraft availability owing to numerous shot cancellations. Area Evelyn was centered on Enewetak Lagoon, 270° clockwise through north to 90°, with a radius of 300 nmi (556 km), plus a rectangular strip 60 nmi and 600 nmi (1,111 km) (111 km) wide long, immediately adjacent to the south. Since the upper airborne particle trajectories normally moved toward the east, this smaller area could be searched faster time before H-hour) (and therefore at a later starting and with fewer aircraft, taking advantage of the rela- tively clear easternmost portion of the 450-<nmi (833~-km) danger zone without necessitating detailed searching. Figure 16 shows the locations of these various areas. Fallout Prediction The Radsafe Office prepared the fallout predictions, delineated the danger zone and radex areas, and presented the predictions at command briefings before each shot. 108