TG.Cmpll. For a direct flight into destination a pos.lne. , advanced or not , is of no use since @ ETA both the elevation and the azimuth of (for this case) the sun have changed since sunrise when the LOP was established. A very good navigator could attain 5% DR uncertainty at the end of a long range over ocean flight ; for a last check point at 500 mls off destination this accounts for a 12 1/2 miles radius circle of uncertainty , representing the direct approach risk of overshoot being 100% if the target visual range is less. From 1,000 ft altitude westwards the optical field width of Howland is 1 arcmin for 12.5 mls distance in clear air, this being the lower limit of resolution for the eye to form an image. No dutyful navigator would venture a direct spot on hit for Howland , with the sun ahead and early morning haze present. The "18 hrs time" @ takeoff message , btw , was not an ETA , but an assessment of duration.