TIGHAR
Amelia Earhart Search Forum => Celestial choir => Topic started by: Cameron Scott on March 21, 2010, 09:14:58 PM
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Hello,
Is the bearing known that AE was flying from on Lae to Howland Is?
Also, what were the weather and light conditions that were in the area of Howland Is in the morning when she disapeared?
Thanks,
Cam
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Is the bearing known that AE was flying from on Lae to Howland Is?
There wasn't one bearing.
If she was approximating a great circle route (the shortest distance between
two points), she would have flown a number of different bearings, as Lindbergh
did across the Atlantic.
And the next bearing chosen after finishing a segment would depend on
dead reckoning about the degree to which wind might have blown the
plane off course during the last segment--or last several segments.
Also, what were the weather and light conditions that were in the area of Howland Is in the morning when she disappeared?
If I remember correctly, it was cloudy only off to the northwest. That's why the Itasca sailed off in that direction post-haste, thinking that if AE and FN had been anywhere else in the sky, they'd surely have spotted the island.
Links to several articles on this page (http://tighar.org/wiki/Coast_Guard_search) that deal with the scene on the Itasca.
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Marty is correct about the changing compass heading but, of course, the other answer is, "Nobody knows what heading she was actually flying."
As to weather, the observations taken aboard Itasca and on Howland indicate that it was a typical Central Pacific morning with scattered cumulus clouds at about 2,000 feet. The clouds did appear to be less scattered and more broken to the northwest.
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Thanks for all the help.
So she would have been flying in a circle route like when an airliner flying from North America to Europe would fly north to the Greenland/Iceland area before coming back south?
If this is the case would it be plausible that since she was in the southern hemisphere, she would have flown south and then north? This would have put her on a general course coming from the South East towards Howland Is?
This is contrary to where the Itasca searched. Is it plausible that they knew more about her flight plan or was it just the clouds blocking the view of the island?
Cam
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Her final heading should have been 78° so she was approaching from the west/southwest headed east/northeast. We know what the Itasca knew because we have all the pre-flight radio messages.
It's all in the book, Finding Amelia - the true story of the Earhart disappearance - available in soft cover for a mere pittance from amazon or in hard-cover with data-DVD, signed by the author, from TIGHAR at http://tighar.org/TIGHAR_Store/tigharstore.html
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Thanks for the quick reply. I think I will have to get the book. However I still have questions and no book so please bear with me.
So from the link that was posted about the first 24hrs of the search, it said that the Capt thought she only had 30 mins of fuel left. From revious flights it can be estimated that she had 4 hours left. So is it plausible that at 105 kts/hr she should be able to fly another 420 'ish' NM?
I also read that she was believed to be close to Howland Is by the strength of her broadcast. What is considered close? Are we talking 10 NM, 50 NM or 100 NM ranges?
Cam
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So is it plausible that at 105 kts/hr she should be able to fly another 420 'ish' NM?
She wouldn't need to fly anything like that far. It's 356 nm from Howland to Niku. If she hit the LOP 100 nm southeast of Howland she would only have to go 256 nm. If she hit the LOP 200 nm southeast of Howl;and she would only need to go 156 nm.
The strength of the radio broadcasts suggest that she was at least 80 nm and perhaps as much as 210 nm from Howland. See "The 3105 Donut" in http://tighar.org/TTracks/2008Vol_24/1008.pdf
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I guess this is the whole mystery, which you guys know far better than I do. I am just getting into this and I can't seem to shut down my computer because it is so interesting.
If she joined the LOP at 100 or 80nm she would have had the shorter route but would she have seen Niku?
If she turned SE along 157 just before Howland became visable at 1000ft, she would have been taken just West of Niku (within visual range). However, this line would have taken her past Baker Island which would have also been with in visual range.
I think the key is her ability to see Niku and putting her in a position to see it. With the radio traffic that was recorded, basically we have that she thought she was on them but couldn't see the Island and that she turned on 157. If she was travelling at 1000 ft when she sent the message, is it plausible to believe that she began to climb higher with time (and maybe panic), trying to get a better view?
Cam
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I don't think she was ever anywhere near Howland. I think they hit the LOP about 200 miles southeast of Howland. When she said "We must be on you ..." all she was saying was that they had reached the LOP which Noonan had calculated fell through Howland, Baker,near Mckean, and close to Gardner (Niku). They probably explored northwestward (337°) for about 20 minutes but that still didn't bring them within visual range of Baker. They then turned around and re-traced their steps and kept going until Gardner came in sight. Unlike Howland, Baker, or McKean; Gardner has a large turquoise-colored lagoon that makes it far more visible from the air than the other islands.
Climbing would create problems because if you're above a scattered cloud deck you can only see what is directly below through the gaps in the clouds.
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Hello Ric,
Thanks for all the reply's. This is all very interesting.
For VHF transmission, you can deduct line of sight using the formula (the square root of Alt in feet multiplied by 1.23). With this you get just under 39 NM. This is a little out there for what the human eye can actually see. I am pretty sure that the flyers would have also had Bino's. So what would have been a reasonable estimate for what they could see? Would 39 NM be alright for thier field of view or would something smaller like 20 NM be better? I guess this is all relative to thier eye sight which is something we will never know.
I agree that she most likely came onto the LOP South of Howland Island. However, is it possible that she did not actually hit 157/377 in line with Howland? Could she have turned south east ten or twenty minutes early? I know this would be difficult because Noonan would have been watching a clock but the fact that they are missing, denotes that mistakes were made. 157/377 is a SE course and would have taken them towards Niku if they were West of Howland and Baker Islands. If they were east of 157/337 in line with Howland, it would have taken them farther out of sight of Niku.
Would an engine on an Electra work if the props were damaged? By this I mean the props could be pulled back from the force of landing right up to being ripped right off. They would have needed them to keep the engine cool but if they are starting and stopping the engine for short amounts of time when recharging this might have not been needed. Could they do it?
I don't think this makes any difference, just musings really.
Cam
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For VHF transmission, you can deduce line of sight using the formula (the square root of Alt in feet multiplied by 1.23). With this you get just under 39 NM. This is a little out there for what the human eye can actually see. I am pretty sure that the flyers would have also had Bino's.
I'm pretty sure that no binoculars were listed in the Luke Field Inventory. (http://tighar.org/Projects/Earhart/Documents/Luke_Field.html)
It's not just a matter of "seeing" the island, but of recognizing that what you are looking at is the island. It's apparently quite hard to differentiate Howland from the normal pattern of cloud shadows on the surface of the water.
The Waitt Institute for Discovery has an excellent video on this page (http://log.searchforamelia.org/wow-wheres-howland) that demonstrates how difficult it is to spot Howland Island from the air.
... is it possible that she did not actually hit 157/377 in line with Howland?
Anything is possible, isn't it?
The increasing strength of the radio signals suggests that they were getting close. Ric already pointed you to the argument about how close that might have been. We know they missed Howland. There are probably lots of possible ways of doing that.
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Even a nick in the tip of a prop blade can throw it out of balance and an unbalanced prop can tear an engine off its mounts. I don't think it's reasonable to postulate that the aircraft sustained significant propeller damage in the landing.
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The Luke Field inventory made by the Army after Earhart's failed first attempt did include " Bausch & Lomb Field Glasses, 6 x 30 Serial No. 221939 with carrying case". I, too, think binoculars would be very important to have, but there is no way of knowing if she carried them when she departed Lae.
It would also seem logical that Earhart was short of Howland Island when she maneuvered on 157/337. Had she been east of Howland with the sun to her back, she may have had a better shot at seeing the island.
Rick J
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The Luke Field inventory made by the Army after Earhart's failed first attempt did include "Bausch & Lomb Field Glasses, 6 x 30 Serial No. 221939 with carrying case". I, too, think binoculars would be very important to have, but there is no way of knowing if she carried them when she departed Lae.
Thanks for the correction, Rick! I didn't take time to re-read the inventory before I replied. My bad!
It's actually a middling-important question. Folks have often speculated that AE may have carried a lens from the sextant to start fires. If she had any feel for lenses, she might have tried getting one out of the binoculars to use as a firestarter rather than using the tiny eyepiece from the sextant.
If they had the binoculars with them ...
If her mind worked that way ...
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It would also seem logical that Earhart was short of Howland Island when she maneuvered on 157/337.
I don't agree that it is logical that Earhart was short of the LOP that passed through Howland. Her arrival on that line was governed by Noonan's calculations that advanced his 157/337 sunrise LOP by Dead Reckoning until it fell through Howland (and coincidentally near Baker, McKean and Gardner). I know of no reason to think that Noonan's calculation would not be accurate within about 10 miles. When Earhart said at 1912Z, "We must be on you but cannot see you.." all she was saying is that the clock said they had reached the advanced LOP. I think they were probably within 10 miles of the line but about 200 miles southeast of Howland.
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Yesterday was a long day at the Armoury and I didn't have time to reply.
I just finished reading the Hooven report. He puts a lot of time on the possible landing at McKean Island. I didn't really know how to say this until I read the article and talked with a friend of mine who is a bush pilot up here in Canada.
If she was on a line of 157/337, she would have seen McKean Island first and possibly landed there. I have read your report on McKean island where you found nothing and there is no evidence for a landing on McKean. From the pictures it looks like she could have landed there. So if she didn't land there, it can be for the only two reasons I can think of. Either she didn't like the island to land on or she couldn't see the island. I think it is more likely that she couldn't see the island from the prevous posts by Ric on the matter. So that leaves two reasons why she couldn't see the island. Either the conditions of sight were bad or she turned before the line with Howland. The line 157/337 would lead her towards Niku even if she entered onto it early. If she entered on to it later, then she would have been more likely to land on McKean or miss them all together.
My friend says that as a pilot flying into remote areas in the sub arctic, they follow certain principles that would have been the same to AE. They fly on thier course until the clock is up and then they start looking if they haven't found thier landing strip. I do not know if the Electra had a clock or if they were just taking bearings off of the sun. As my friend says, if you are lost and short on fuel, you put down as soon as possible. So if this was the case for AE's line of thought, she would have probably tried to put down on McKean which she probably would have seen first.
Now I don't know a lot about navigating by air but I do it on the ground a lot. In the last post by Ric, it is layed out pretty clearly why Noonan probably would not have made a mistake and ended up turning before the 157/337 line with Howland. I have seen many people who are tired and stressed become impatient. They end up improperly pacing thier legs and end up turning on a false way point before they actually reach it.
I guess that what I am trying to ask is doesn't this make it a stronger case for Niku if they turned before the 157/337 line with Howland?
Cam
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... I do not know if the Electra had a clock or if they were just taking bearings off of the sun.
Fred had a chronometer. They spent a couple of extra days in Lae (http://tighar.org/wiki/Delayed_in_Lae) to get a good time check before taking off for Howland.
... I guess that what I am trying to ask is doesn't this make it a stronger case for Niku if they turned before the 157/337 line with Howland?
In the absence of evidence from the cockpit, how can anyone decide rationally whether they turned on or before the line?
If the evidence points to Niku (as it seems to me to do), then the question of why they missed or skipped McKean is moot (arguable but irrelevant).
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200 nm southeast ? Really ? that far off ? I guess I need to go back and sharpen the pencil, but that seems like a lot me ! I've been trying to learn about navigation in this era, and had assumed that they would have at least used some form of offset navigation. http://tighar.org/Projects/Earhart/forum/FAQs/offset.htm Even if they planned to use the radio, a small offset (maybe 20 miles) would at least increase the odds that they need to turn right when they got the advanced LOP.
I assume that Noonan would be able to get both a Lat and a Long fix at sunrise, is that true ? If that was about 200 nm out or roughly 2 hrs (assuming 105 kts), then that would be roughly a 45 degree heading error to be 200 nm off.
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200 nm southeast ? Really ? that far off ? I guess I need to go back and sharpen the pencil, but that seems like a lot me ! I've been trying to learn about navigation in this era, and had assumed that they would have at least used some form of offset navigation.
The only (weak) evidence against your assumption is that the last transmission (http://tighar.org/wiki/%22We_are_on_the_line_157_337%22) said they were flying "north and south" on the line of position (http://tighar.org/Projects/Earhart/forum/FAQs/navigation.html). If they had used an offset, it seems to me that AE would have said, "We are flying north on the line" or "We are flying south on the line."
I assume that Noonan would be able to get both a Lat and a Long fix at sunrise, is that true?
Only if he could shoot another celestial body (the moon or a planet or a star) just before or just after getting the LOP from the sun observation. The observation of the time of sunrise, all by itself, just gives information about longitude. From navigation tables, Fred could derive the angle of the LOP at sunrise (337/157 in that part of the world at that time of year).
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This is all very interesting. I can't wait to see the results of the May expedition.
I now see that it was probably very improbable that they turned on 157/337 early. I guess my line of thinking was that if they were on the right course (78), or even just south of their course, they would have needed to turn early in order to not see the islands. I thought this would he to be the case if they flew north and south. They would have still hit Howland turning early but with FN's skill, I don't think this was the case now.
I think that we are all kind of saying the same thing. When I am navigating across country, I will orient myself so that I know where a road or railway is, just in case I become geographically embarrassed. This is a safety net and I think that this is exactly what FN did. In the Hooven report he says this along with the people on this board. It makes a lot of sense. I was wondering why she would fly for 1, 2, 3 or more hours south. If she was being reassured that she would find land, she would have kept going.
So does anyone have an idea how did she make a mistake from 80-200 NM?
Cam
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So does anyone have an idea how did she make a mistake from 80-200 NM?
Miscalculation of the strength and/or direction of the wind?
Too many clouds to get good "cuts" (two or three intersecting LOPs derived from star sightings) during the night?
Too much confidence in radio direction finding?
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Is there anyway to figure out when or how some of these effects would have started to take place? There was the sighting of the ship along the way so I guess it would have been after that.
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Is there anyway to figure out when or how some of these effects would have started to take place?
I don't think we can answer that question.
Here are the radio logs of the Itasca. (http://tighar.org/Projects/Earhart/Research/Bulletins/37_ItascaLogs/Itascalog.html)
On this page (http://tighar.org/Projects/Earhart/Research/ResearchPapers/researchlist.html), under "Final Flight," you can see what Randy Jacobson makes of the information in the logs.
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I tend to agree with Ric, AE/FN ended up South of Howland/Baker. Why?
FN would most probably have targeted an offset to the south of Howland, somewhere between Howland and Baker. This would give him some assurance that he could find where he wanted to be.
If he gets to the LOP and turns north (if aiming between the islands) he is sure to run into Howland. If he turns south (under the same situation) he is sure to run into Baker and thus knows he is south of Howland, a 180 and wa-la Howland. If he gets to the LOP and turns north and no Howland or Baker he knows that his only way out of the mess is to turn south and look for any island.
Think this through. If his offset was to the north and they find nothing then they do a 180 and fly south, if they can’t find anything (Howland or Baker) within a reasonable time FN knows they are in deep do-do; they must really be a long way north with no options and south is his only salvation.
Ted Campbell
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I tend to agree with Ric, AE/FN ended up South of Howland/Baker. ...
Randy Jacobson's Monte Carlo simulation (http://tighar.org/wiki/Monte_Carlo_Simulation_of_Flight) also supports that as the most probable outcome.
I'm not in a position to defend the Monte Carlo method. (http://en.wikipedia.org/wiki/Monte_carlo_method) I can see that it is a way of dealing with aggregates of probabilities that are only very loosely bounded by the information available. In the article, Randy summarizes all of the navigation information available from the messages received from NR16020 and explains why we cannot correlate the positions given with the time at which the position was transmitted.
The two charts at the bottom of the page summarize the results. The first chart shows where AE and FN thought that they were (very close to the vicinity of Howland). The second chart shows a cloud of probabilities about where they actually were (SW of where they thought they were).
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Her final heading should have been 78° so she was approaching from the west/southwest headed east/northeast. We know what the Itasca knew because we have all the pre-flight radio messages.
It's all in the book, Finding Amelia - the true story of the Earhart disappearance - available in soft cover for a mere pittance from amazon or in hard-cover with data-DVD, signed by the author, from TIGHAR at http://tighar.org/TIGHAR_Store/tigharstore.html
I don't agree that it is logical that Earhart was short of the LOP that passed through Howland. Her arrival on that line was governed by Noonan's calculations that advanced his 157/337 sunrise LOP by Dead Reckoning until it fell through Howland (and coincidentally near Baker, McKean and Gardner). I know of no reason to think that Noonan's calculation would not be accurate within about 10 miles. When Earhart said at 1912Z, "We must be on you but cannot see you.." all she was saying is that the clock said they had reached the advanced LOP. I think they were probably within 10 miles of the line but about 200 miles southeast of Howland.
Now if they hit the LOP about 200miles southeast of Howland as you state, then what Noonan didn’t have a clue about was the direction and velocity of the wind. To get blown 200 miles off course means that little or no course correction was made for the wind which appears to have been a left quartering headwind.
I think that Noonan probably hit the LOP fairly accurately because when he clocked the sunrise, he knew, according to the almanac, just where the dawn line that he was on was located, or how far west he was from the LOP through Howland. He knew that sunrise at Howland was at 1745Z and if he was about 200 miles out, he saw the sunrise about 1757Z, so he knew how far he was from the Howland LOP.
In the Monte Carlo Simulation, Randy Jacobson states that “ Thus, we actually calculate much of the time during the MC simulations that Earhart was experiencing 26 knot winds from roughly 58 degrees, rather than the 18 knots winds for the 68 degrees as forecast.”
Depending on the course correction or crab angle necessary to track on the heading to Howland, the 1 in 60 rule would indicate that they could have gone about 10-20 miles off course to the south for every 60 miles traveled. To have drifted as much as 200 miles south, they would have to had strong winds out of the NNE, 030-035 degrees, at about 35 knots. This would put the winds about 45 degrees off the nose of the Electra equating to about a 26 knot crosswind. ( w/v=35deg/35knots,relative angle=45degrees=45/60x35=26knots crosswind component)
It was reported that the plane was heard passing over Tabituea which is 615 miles from Howland on a 078 degree heading. Encountering the stronger headwinds at this point and assuming a true airspeed of 135 knots for about the last 620-675 miles of the flight, it is possible for them to have hit the LOP 200 miles southeast of Howland as without a crosswind correction they would have drifted south all the way to the LOP with a groundspeed of 115 knots culminating a track error of about 18 degrees. (track error=distance off track/distance traveled, DO/DT x 60, 200/675x60=18 degrees). A lesser crosswind component would have put them farther north on the LOP even as close as the 80 mile donut hole which seems to me to be more likely.
It is known that Noonan utilized a E6B computer (Dalton Mark VII navigation computer) or an earlier version of one, however, he would need wind data to figure a heading. The wind correction angle would be calculated as wind speed /TASx60=12degrees, so to track on a 078 degree heading with a 26 knot crosswind component, Earhart would have to fly on a compass heading of 066 degrees for the last 615 miles of the flight.
In my flying experience over water/off shore many years ago, I was taught to estimated the wind by looking at the water. Apparently this did not work for Noonan because he could not see the water until sunrise or perhaps at twilight. Somewhere in that last leg of the flight, there should have been some indication of what the wind was doing or had already done to their direction of travel. Perhaps by the time they hit the LOP, Noonan had it figured out that they were well south but not sure enough to fly 200 miles to the northwest looking for Howland and thought it more prudent to look for land to the southeast.
In a web page on this site authored by Randall S. Jacobson, Ph.D., it is stated that:
“In summary, the weather for Earhart’s approach to Howland indicated good visibility, winds aloft probably about 10 knots from the east, well below the 20 knots forecast the previous day by the Fleet Air Base.”
These weather conditions seem to be inconsistent with the premise that strong northeasterly winds blew Earhart 200 miles off course to the south.
If it was not the wind that caused them to drift so far south, then what caused that kind of error in navigation? According to the photos of the cockpit that I have seen, AE appears to have had both a heading indicator or what looks like a J2 compass along with a magnetic compass. I also see an artificial horizon, attitude indicator, turn and bank indicator, air speed indicator, altimeter and rate of climb and descent indicator. The auto pilot should have held the correct heading without difficulty.
The short of it is that Earhart had all of the instruments necessary to maintain straight and level flight and to maintain course. Obviously there was a disastrous failure in navigation and I have been unable to see any indications of this in the past history of Noonan’s performance other than statements made by him as to the difficulties in determining accurate position fixes.. Noonan had previously stated that he felt that the greatest problem he had while navigating was determining the drift angle of their course which could have been his downfall in the flight to Howland.
In a written report, dated April 29, 1935, submitted by Noonan when he was the navigator of a Pan American Clipper, he stated that aerial navigation, like surface navigation is an “inexact science.” He went on to say that “ hence is it impossible on an extended flight to obtain consistently accurate fixes by any single method, or by any combination of methods. But by understanding of the weaknesses of each method, it should be possible to greatly minimize the errors inherent in all of them.” He also asserted that his experience has shown that a “fix” within the distance of ten to fifteen miles of the true position is about the average accuracy which can be expected in aerial navigation.
It appears then that Noonan was probably navigating the best he could with the information that he could get and once on the LOP was unable to obtain an accurate fix and thus he and Earhart flew into eternity.
In the Purdue archive photos are images of notes (http://earchives.lib.purdue.edu/u?/earhart,2146) that Noonan would pass to Earhart during the flight. These notes appear to be on small slips of paper, are poorly written and usually give her a position report and a heading to fly. On one note she scribbled, “what put us north?”. This seems to indicate that she did not have the foggiest clue as to why she was holding a certain heading. Passing notes on a stick or handing them to her seems so ridiculous that it is hard to imagine. If it weren’t so pathetic it would be funny.
Many of the photos of Noonan show him with a cigarette (http://earchives.lib.purdue.edu/u?/earhart,287) hanging in his mouth. Wonder if he smoked while en route? When fully loaded, the 10E was like a gas tanker flying through the sky. Fumes were probably everywhere. It is quite possible that Noonan flipped opened his Zippo and blew the Electra to smithereens, but I suppose the Navy would have found some debris.
At any rate, this is an interesting project, hope you do well. I have been reading the voluminous forums and documents posted on this site for several years now and am nowhere near finished. I have read excerpts and reviews of the book, Finding Amelia, and will acquire a copy soon.
I know how it feels to be lost over water and no man made objects nor land in sight in any direction. When I first began offshore flying, we had no nav aids and had to dead reckon a course to production platforms, sometimes in low ceiling and vis less than 1 mile. If you missed the platform, you had no idea which way to turn. At that point you would fly a little further on the line and then left and right for a short distance and then if still lost, the only option was to reverse course to land.
Flying to land was the ace in the hole and I feel that this is what AE and Noonan did, fly to nearest known land. I have never known an aviator who would fly in a search pattern or circle around until they ran out of gas. Of course I did not know Amelia Earhart either.