Gary,
I was looking over your links and found this one:
https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxmcmVkaWVub29uYW58Z3g6M2I5OTVhMWZmMmI4ZDFiZA&pli=1---
Landfalls - The safest way to get to destination
Landfalls are of two types: course line landfalls and speed line landfalls.
Course Line Landfall
The easiest landfall to fly and things being equal, the most accurate. is the course line landfall.
1. Observe a celestial body that gives a course line, line of position. Plot it on your Mercator chart
2. Advance the line of position through destination parallel to the one you just plotted.
3. Fly directly to the line of position through destination and turn toward destination.
4. Stay on this line of position until another line of position shows you to be off course.
5. Then repeat the process. But stay on a line of position through destinatiun. There is no ETA in a landfall other than your best known ground speed.
Speed Line Landfall
Because a course line is at times the more difficult type of line of position to observe, and because sometimes only speed lines are available, you will also fly a speed line landÃall.
In this type of landfall fly definitely to one side of destination. When you reach the speed line through destination, turn and fly into destination.
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It seems to me (with zero expertise in this area) that Course Line Landfall requires being able to measure some celestial body (Sun or stars). This would also imply (to me) that in order for Earhart to end up on the 337/157, they must have had a approach heading 90 degrees from the advanced line of position (Howland) and that they would have definitely had some celestial reference to use. Again, to me, this seems like a risky strategy in pre-dawn conditions, perhaps overcast, where you cannot be certain that you will find any reference. This approach only works assuming you have some reference correct?
The Speed Line Landfall on the other hand requires that you chose a point that is "definitely to one side of destination". This might be used when you may perhaps have only ground speed data that you have recorded since your last verified position correct?
So given the above advice, are we not just debating over the the degree of being "definitely to one side of destination" if a Speed Line Landfall was used?
Thanks in advance.