Amelia Earhart Search Forum > Celestial choir
LOP-Possible stupid question
Chris Johnson:
I hold my hands up and admit that I am no navigator but have a question regarding the LOP that I hope doesn’t become another theory battle between our esteemed navigational colleagues.
I may have asked something similar before so be patient.
FN and AE miss Howland Island but FN’s observations and calculations say he has reached the LOP 157 – 337. How wide/broad is this line for them to fly up/down? Could AE not just watch a compass to stay on the LOP with FN then taking shots to adjust for wind etc?
In this way could they then not reach the ‘catchers mitt’ of the Phoenix island?
Martin X. Moleski, SJ:
--- Quote from: Chris Johnson on August 18, 2011, 05:44:01 AM ---FN and AE miss Howland Island but FN’s observations and calculations say he has reached the LOP 157 – 337. How wide/broad is this line for them to fly up/down?
--- End quote ---
A line, considered as a mathematical abstraction, has no width.
A line of position, considered as "the amount of territory visible from the aircraft" has a width that is variable, depending on weather, altitude, and the field of view from the aircraft.
Did you miss the discussion of how to visualize the LOP?
--- Quote ---Could AE not just watch a compass to stay on the LOP with FN then taking shots to adjust for wind etc?
In this way could they then not reach the ‘catchers mitt’ of the Phoenix island?
--- End quote ---
Gary LaPook has given several links to his website where he argues that a navigator would have to continually revise position estimates in order to end up in the vicinity of Nikumaroro.
All that we know about what Fred did or did not do ends with the final received transmission: "We are on the line 157 337. Will repeat the message. We will repeat this on 6210 kcs. Wait. We are running [on] line [north and south]."
We do not know how long they stayed on that line.
We do not know how far east or west of Howland that line was, in fact.
We may surmise that Fred thoughtthat that line ran through Howland (there was no other reason for them to have identified that line or to have turned on it unless this was the case).
We can see that that line points down toward the vicinity of Niku.
We don't know what other position information Fred might have derived from later observations.
We don't know what other headings he might have told Amelia to fly.
If Earhart and Noonan ended up on Niku, we don't know exactly how they got there--on purpose or by accident. In 1937, the Navy thought it was worthwhile to search there. In 1988, a couple of seasoned military navigators, Tom Gannon and Tom Willi (the "two Toms"), persuaded TIGHAR that Niku was worth exploring. Stuff happened, and here we are today, still wondering whether the Niku hypothesis is correct.
Finding the aircraft in Gary LaPook's search area would disprove the Niku hypothesis. Finding the aircraft on or near Niku would disprove Gary's hypothesis that they splashed and sank near Howland.
Chris Johnson:
Thanks Marty
Missed the 'visualise' discussion, might just answer my questions.
Its Reading Mr LaPooks site that makes me ask these questions to try and understand the whole argument.
Harry Howe, Jr.:
Chris
I don't think there are any "stupid" questions, except the question not asked.
I have one of my own. If I am not mistaken the plane was equipped with a Sperry AutoGyro Autopilot. Anyone have any info on its capabilities?? Surely, it would have been used to maintain course on the long journey.
It also had a drift indicator which, I assume, would give info relative to wind drift and allow corrections to be made. Then, how in the world did they miss Howland? Maybe Howland was mislocated on the chart FN used for his course planning?
h.a.c. van asten:
First and evidently the recorded aircraft progression line did not by far cover the sun line as advanced over Howland´s true coordinates , secondly an on board compass pointing flight in any direction including north gives no resolution of the coordinates you are over .