Copyright ©2009 by Paul Niquette. All rights reserved.
|One solution to the
puzzle is shown in the
schematic flight plan on the right. It calls for
deliberately taking up a heading
to the right of the direct course by an angle that
corresponds to the maximum expected steering error
during the over-water flight.
Doing that removes all ambiguity about
which way to turn if the destination is not
immediately identified upon reaching the shoreline:
Specifically one simply turns left and follows
Obviously, the course line could have been intentionally offset to the left, with turning to the right after completing the over-water flight. The decision about which plan to adopt may be influenced by several factors...
Having departed PAJAR, the flight was subject to the indicated course errors, such that at the extremes the planned route would cross Highway 101 too far away to see the airport runway on either side of the plane. The red arrows show the possibilities of turning the wrong way. The distance for that leg was only 14 nautical miles. With a full hour of fuel on board, the situation hardly presented any kind of danger.
Turning the wrong way, though, would
have been an embarrassment for the pilot.
After more than two hours aloft, my passengers, for
personal reasons, were eager to get on the ground.
Accordingly, I decided to apply Landfall Navigating by taking up a heading of 055 (10 degrees to the right of the intended course) thereby obviating a turn away from the airport, as indicated by the green arrows in the sketch on the right.
The procedure will often be advisable even when the pilot has no visible "landfall" line but instead an elapsed time flying at a known groundspeed from some previous fix.
Consider the case of dead reckoning to a waypoint surrounded by desert or a small island in the middle of an ocean. Expect to see Landfall Navigating featured in Live Reckoning, another in a series of puzzles that concludes with Which Way Amelia? Along the way, sophisticated solvers may actually solve the most famous puzzle in aviation history.