I want to know why the flight was so far south? Noonan was an "expert navigator" and was very professional in his work. So How could he have been so far off? Unless in the late 30's that was considered accurate navigating?
Randy Jacobson's article on his Monte Carlo Simulation discusses why he thinks ending up SSW of Howland at the time of the last transmission is the most probable outcome for the flight.
The plan for the flight was for Noonan to get close enough for Radio Direction Finding to guide them to Howland. He did an excellent job doing so. They did not succeed because there were many failures in communication.
See also "Air Navigation: State of the Art in 1937" and the articles to which it links.
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No, they didn't plan to rely solely on the radio to find the island but planned on having two separate redundant methods either one of which, all by itself, was capable of taking them to a safe landing at Howland.
When you jump out of an airplane you have two separate, independent parachutes attached to
your harness. If the first one fails then the other one will get you back to earth safely. This is the
principal of redundancy. No one jumps with just one and-a-half parachutes.
This principle of redundancy has been well known in aviation forever. We pilots want dual
everything, dual navigation radios, dual communication radios, aircraft engines have two
separate ignition systems with two spark plugs in each cylinder, two engines each with two fuel
pumps with each fuel pump powered by a separate power source, two different sets of flight
instruments each also powered by a different power source, a second method for lowering the
landing gear, etc., etc.
It certainly makes sense that they planned to use their on board RDF to home in on the Itasca’s
transmissions when they came within range since it is a very convenient way to navigate and it
gets more accurate as you get closer to the transmitter. Ric points out that there is no proof that
Noonan ever used the landfall method for finding an island when flying for Pan Am. So What?
Flying a landfall takes you out of the way and adds time to the flight so if on the Pan Am flights they were receiving
radio bearings as they approached their destination then there would be no reason that Noonan
would then go out of his way to do the landfall. There is also no proof that I have ever used a fire
extinguisher (because I never have) but I sure know how to do it and I would use a fire
extinguisher if the need ever arose. Noonan knew the technique and would have used it if he needed to.
Earhart and Noonan must have appreciated the very real
possibility that their radio would not be working at that point based on the unreliability of radios
in 1937 in general and their own experience with their own radios which failed them on many
occasions while flying around he world.
I think this logic applies to Earhart and Noonan’s planning to find Howland, they planned to have
two separate, independent, redundant methods with which they could find the island, radio
bearings and celestial. Either method, by itself, would have been good enough to lead them
safely to Howland. You don't want to put all of your eggs in one basket.
So what proof do we have that they believed that celestial was good enough, by itself, to get them
to Howland so that it provided a redundant method to the use of the unreliable radio? We can
break this down into separate questions.
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1. Is celestial navigation accurate enough to find Howland?
Proof and evidence:
A. )I just used this method three weeks ago and it worked perfectly. I have also used it many times in the
past and it has always worked for me. See
http://www.fer3.com/arc/m2.aspx?i=116311&y=201104 B.) Every flight navigation manual teaches this method.
“Landfall the safest way get to destination”
I have posted excerpts from eleven flight navigation manuals that prove this point here:
https://sites.google.com/site/fredienoonan/topics/landfall-procedure C.) Pelegreno’s navigator, Bill Polhemus, used a landfall and it brought them to Howland.
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2. Was Noonan aware of this technique?
Proof and evidence:
A.) The technique was used in 1922 by Gago Coutinho to find several small islands on the first flight
across the South Atlantic. Admiral Coutinho had an audience with the Pope about his
accomplishment and it was well publicised world wide.
B.) Sir Francis Chichester also used the technique to find two small islands when he crossed the
Tasman Sea in 1931 and he extensively publicised his flight in his 1933 book, “Seaplane Solo.”
C.) A well developed methodolgy for this technique was printed in “Flight Navigation” 1938 ed. by
Noonan’s friend, Philip Van Horn Weems.
https://sites.google.com/site/fredienoonan/resources/weems D.) Noonan was in very frequent contact with Weems sharing their knowledge of flight navigation so
it would be hard to believe that Noonan had not discussed this technique with Weems.
E.) Noonan expected that his celestial navigation was accurate
all by itself for them to find Howland if the radio did not work. Since we know that the radio did
not work we know that Noonan was forced to use the celestial which would have taken them a
bit out of the way but should have gotten them to Howland. It was more reliable than the
unreliable radio but for some reason something went wrong with both of the redundant methods
that they had to complete the flight.
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3. How do we know they didn’t just plan to use radio to find Howland?
Proof and evidence:
A.) They delayed their departure from Lae for two days so that Noonan could check his
chronometers. This would not have been necessary if they did not plan to use celestial to actually
find the island. Accurate time is only necessary for determining longitude it is not necessary for
determining latitude. If they were only planning to get close enough to Howland to pick up the
radio signal from Itasca then they didn’t need to accurately know their longitude. Since they were
flying toward the east they only needed to know their latitude accurately enough to make sure
that they did not pass Howland too far to the north or south to pick up the radio signal and the
radio signals could be heard for hundreds of miles. If Noonan’s chronometer was wrong by an
entire week their latitude would only be in error by 15 miles so they would certainly pass close
enough to Itasca to hear the radio signal. This error in latitude would be caused by the change in
the sun’s declination, its location north and south equivelent to the sun’s latitude. You can see
the change in the sun’s declination in the 1937 Nautical Almanac, page 22:
https://sites.google.com/site/fredienoonan/resources/nautical-almanac-1937------------------------------------------------------------------------------
B.) If Earhart planned on relying only on radio to find the island then she didn’t need a navigator since
dead reckoning all the way from Lae was accurate enough to get her within radio range of Itasca
The range of the RDF in the plane that Earhart planned to use to home in on Itasca’s signals was
at least 250 NM.
C.) I know this based on my own experience. Many times I have homed on WLS in Chicago all the way
from Florida, a distance of a thousand NM. Two months ago while I was on Kauai Hawaii I used a small
portable radio to measure a bearing on radio station KFI in Los Angles which, by coincidence, was
2222 NM away, exactly the same distance as from Lae to Howland. So we know that low frequency
signals can travel this far, however the station I was listening to put our 50,000 watts which is a hundred
times more than Itasca's radio which only put out 500 watts. But the range of a ground wave, in general,
varies with the square root of the power output. KFI's signal was a hundred times as powerful as Itasca's
so its range should be ten times greater, or to put it another way, we can expect Itasca's signal to go one-tenth
as far as KFI's or 222 NM
D.) I also have an old chart showing a fix I got on a radio beacon on the island of Flores in the Azores. I
crossed the radio bearing with a sun line and the fix was 230 NM west of Flores. I know I had
been receiving the radio signal for a long time before I took the sun line so I know that I could
receive that signal at least 300 NM from the transmitter.
E.) I have also flown on route A-17 from Bimini to Grand Turk, a distance of 518 NM, on the way to Puerto Rico and was able to hear the radio
beacons on those islands at least 258 NM away. Grand Turk only puts out 400 watts, Itasca put out 500 watts so
its range should be even longer.
F.) But it is not just my experience to rely on, the government agency that impemented route A-17 also had to test to be
assured that the radio signals could be heard at the middle of the leg which is 258 NM from each island
radio beacon.
G.) Since the leg from Lae to Howland is 2222 NM and the common estimate
of DR accuracy is 10% of the distance flown then one could expect to
fly the distance from Lae to Howland solely by dead reckoning and
still be confident of coming within 222 NM of Itasca and so be
close enough to pick up the radio signal and track inbound to Howland.
So if AE had been willing to rely only on radio she didn't need Fred. But
obviously they wouldn't just rely on radio.
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It is hard for young people today who have grown up with cell phones,
the internet, TV, satellite dishes and IPODs to have any gut feeling
for the unreliability of radio equipment in the 1930s. Modern
equipment and systems are so reliable people don't even think about it
anymore. But in the '30s comparing the reliability and trust in
complicated pieces of electronic equipment with resistors, capacitors,
and tubes that burned out without warning in your own equipment and in
the transmitting equipment that was not under your control to the
proven reliability of a simple sextant, a book of tables and a clock
(or two clocks for redundancy) and celestial won hands down. That was
why AE hauled Fred's butt all the way around the world.
gl