On Tuesday, Continental Airlines announced plans to being non-stop flights to Auckland, New Zealand from its Houston hub, using the Boeing 787 Dreamliner. Mapping this route with ETOPS contours reveals that it traverses a rather large "no-go" area west of the Galápagos Islands. Using 180-minute ETOPS, the shortest legal path is via a point that is 180 minutes from both ITO and LAX. This route adds about 228 nautical miles (3.5%) over the shortest path, a relatively minor detour.
Another possibility is that Continental plans to use ETOPS Beyond 180 Minutes authority. The FAA describes how an airline may apply for this authorization in paragraph 401 of advisory circular AC 120-42B. With limited 787 operational experience, the flight would still need to stay within 240 minutes flying single-engine time from the nearest suitable alternate, but this only adds about 17 nautical miles (0.3%) to the flight path.
The critical points which define the limits of the no-go areas for the above paths can be determined by plotting the two intersecting ranges which define each point — 180min@(ITO,LAX) and 240min@(ITO,SJD) — using the Great Circle Mapper, which will also display the intersection points of the two ranges. In each of these cases there are two intersection points; the southern point is the point of interest.
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Karl L. Swartz.
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