Navigating the LOP with the offset method.

[Martin X. Moleski, SJ]

OK, folks, we've had one (1) complaint from a Forum member who thinks that the last few replies to h.a.c. have been unfair.

Let's try to elevate the tone, if possible.  If you don't have an argument to make against h.a.c.'s posts, perhaps you could just pass over them in silence.  I don't buy those parts of his posts that I can decode--his conclusion seems to be that AE and FN splashed down within a minute after the last transmission--but, so far, we have not set adherence to the Niku hypothesis as a precondition for participation in the discussion.  In fact, there has been, from time to time, some enthusiasm expressed for the tradition of skepticism as part and parcel of the methods used by scientists.  That's a double-edged sword.  While it licenses us to express doubt about other people's views, it also licenses them to return the favor.

[Chris Owens]

OK, folks, we've had one (1) complaint from a Forum member who thinks that the last few replies to h.a.c. have been unfair.

Let's try to elevate the tone, if possible.  If you don't have an argument to make against h.a.c.'s posts, perhaps you could just pass over them in silence.  I don't buy those parts of his posts that I can decode--his conclusion seems to be that AE and FN splashed down within a minute after the last transmission--but, so far, we have not set adherence to the Niku hypothesis as a precondition for participation in the discussion.  In fact, there has been, from time to time, some enthusiasm expressed for the tradition of skepticism as part and parcel of the methods used by scientists.  That's a double-edged sword.  While it licenses us to express doubt about other people's views, it also licenses them to return the favor.

In response to your reasonable request I have gone back and removed my snarky comment.   But I would suggest that in this particular case, the objection to many of the posts in question does not appear to be based on whether or not the poster subscribes to any particular hypothesis, it is based on the poster's somewhat difficult-to-read style, which some interpret as deliberately obfuscatory.  I suspect that the poster's native language is other than English, and that, accordingly, he should be granted a good measure of consideration before we jump on him for his writing style.

[Chris Johnson]

OK, folks, we've had one (1) complaint from a Forum member who thinks that the last few replies to h.a.c. have been unfair.

Let's try to elevate the tone, if possible.  If you don't have an argument to make against h.a.c.'s posts, perhaps you could just pass over them in silence.  I don't buy those parts of his posts that I can decode--his conclusion seems to be that AE and FN splashed down within a minute after the last transmission--but, so far, we have not set adherence to the Niku hypothesis as a precondition for participation in the discussion.  In fact, there has been, from time to time, some enthusiasm expressed for the tradition of skepticism as part and parcel of the methods used by scientists.  That's a double-edged sword.  While it licenses us to express doubt about other people's views, it also licenses them to return the favor.

In response to your reasonable request I have gone back and removed my snarky comment.   But I would suggest that in this particular case, the objection to many of the posts in question does not appear to be based on whether or not the poster subscribes to any particular hypothesis, it is based on the poster's somewhat difficult-to-read style, which some interpret as deliberately obfuscatory.  I suspect that the poster's native language is other than English, and that, accordingly, he should be granted a good measure of consideration before we jump on him for his writing style.

My guess based on this post is the Netherlands

TdG.Cmpbll . Sounds not very scientifically . I btw for the purpose studied Aircraft Performance Theory at Delft , The Netherlands , U.O.T. , Aeronautical  Faculty , 1988-2004.

[Chris Austin]

If only they'd used their GPS and Sat-phone, all this unpleasantness could have been avoided.



:o .......What?

[h.a.c. van asten]

M.Molsk. The magnetic variation and TC/MC was given for 3 regions by C.S.Williams in the great circle chords listing & chart , see illustration p.29, EJN-2008 article.

[Ted G Campbell]

H. A. C. Van Asten,
Would you just post the point you are trying to make!  Make it as simple as you can so most of us can follow your point.
Thanks,
Ted Campbell

[Monty Fowler]

I'm thinking it's time for another viewing of Amelia ... and even if Fred didn't actually say it, grin at what is surely one of the great movie quotes of all time: "Got room for 180 pounds of -------. ?"

[h.a.c. van asten]

Mr Gillespie ,

You replied several times to my remarks on the One Line Approach having been used or not in the roads of Howland. Your last statement is that the OLA was not common fashion in the era and in addition you say that Pan American Clippers of the 1935-1940 era , on the Alameda via Guam to Manila etc. way , were always flown inbound the range of land RDF stations that homed them straight in after their signal had been received on board . Well then , in document "Francis Chichester , 1922 Portuguese flight , Navigator , p.  238 ,  we read : "April 12 , 1922 . At 1815 navigator found plane to be on a LOP which , extended to the left , cut through the tiny rocky objective. Pilot changed course accordingly and objection was attained" . And on p. 239 : " Pan American World Airways later made island landfalls on transoceanic flights by using the same technique" . It is herewith clear that F.Noonan , navigation officer of the Clipper air services from the beginning, knew the method and that he had experience with the methodology. The term "preventer" for a marine sextant in addition to the bubble sextant/octant may henceforth be transcribed as "in reserve" , namely for the event that an aircraft , already flying low inbound , lost the RDF signal in which case the marine sextant and the unblended horizon would be a perfect godsend.

[Ric Gillespie]

Well then , in document "Francis Chichester , 1922 Portuguese flight , Navigator , p.  238 ,  we read : "April 12 , 1922 . At 1815 navigator found plane to be on a LOP which , extended to the left , cut through the tiny rocky objective. Pilot changed course accordingly and objection was attained" . And on p. 239 : " Pan American World Airways later made island landfalls on transoceanic flights by using the same technique" .

Is that a book or an article?  Who wrote it?  Please provide a proper citation.

[h.a.c. van asten]

R.G. It is a book , as seen by the footnotes. Wil try to find back with Google & report.

[Chris Johnson]

Warning! Stupid question

As it says above!!!!

If you had a LOP and were flying North and South,could you use a simple compass to keep yourself on the line?

(I have zero navigational/pilot knowledge or experience) Its just something I wanted to ask. :)

[Bruce Thomas]

Well then , in document "Francis Chichester , 1922 Portuguese flight , Navigator , p.  238 ,  we read : "April 12 , 1922 . At 1815 navigator found plane to be on a LOP which , extended to the left , cut through the tiny rocky objective. Pilot changed course accordingly and objection was attained" . And on p. 239 : " Pan American World Airways later made island landfalls on transoceanic flights by using the same technique" .

Is that a book or an article?  Who wrote it?  Please provide a proper citation.

Francis Millet Rogers, "Precision astrolabe: Portuguese navigators and transoceanic aviation," Academia Internacional da Cultura Portuguesa; [distributed in the U.S.A. by W. S. Sullwold, Taunton, Mass.], 1971, 397 pages

Google digitized it in 2008 from a copy at the library of the University of California -- Davis, but only snippets can be seen online with Google Books. 

From page 238,

Realizing that the late-afternoon LOP's were trending ever more toward a NS stance, navigator at 1715 recommended to pilot that he turn right and start to cut across the LOP's. At 1815 navigator found plane to be on an LOP which, extended to the left, cut through the tiny rocky objective. Pilot changed course accordingly and objective was attained.

The second quote given by Mr. van Asten is shown to be at the top of page 239, with what appears to be a footnote number of "8".  To see from whom that statement about Pan American's use of the technique came will probably require a visit to a library.  Copies of the book are said to be in the vicinity of Washington, DC, at the Library of Congress, the Smithsonian, NOAA (in Silver Spring, MD), and in the Nimitz Library at the U.S. Naval Academy.

[Chris Owens]

Warning! Stupid question

As it says above!!!!

If you had a LOP and were flying North and South,could you use a simple compass to keep yourself on the line?

(I have zero navigational/pilot knowledge or experience) Its just something I wanted to ask. :)

Not a stupid question.

A compass tells you which direction the nose of the plane is pointing.  That's valuable information, but it doesn't tell you which direction the plane is moving over the ground.  The compass doesn't know if the plane is flying in the same direction it is pointing, sitting on the ground, or moving sideways, etc.

If there were no wind, then the plane would move in the same direction it was pointing, and if you pointed the plane straight South you would end up at some point due South of where you started.  But if there were a wind blowing from the East and if you were to point the plane straight South, then you will end up somewhere to the Southwest, depending upon how fast the wind is blowing relative to how fast you are flying.

[Chris Johnson]

OK bear with me "stupid warning If I knew I was running on a LOP like FN may or may not have plotted, could i not just use the compass to keep a bearing of ?South, South East? to head towards the Phoenix group.  If the wind was against me could I not just keep to a heading that I had in mind?

(this is based upon the idea that as a hill walker in fog/mist and lost if i just keep to a compass bearing that directs me towards something then i should get there?)

[h.a.c. van asten]

Mr.R.G. Book on OLA by PanAm is : F.M.Rogers ,  Precision Astrolabe , W.S.Sullwold , Taunton Mass 1971.