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.