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Author Topic: Tides and the Electra  (Read 13887 times)

Greg Henton

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Tides and the Electra
« on: November 06, 2011, 08:07:34 PM »

I have been poring over this site for the past 3 days, and am absolutely fascinated by it.  Especially the post flight radio messages.  The theory is that EA landed on the corral reef and then was able to broadcast messages that were received in North America and elsewhere for several days after the landing.  And I believe, if I read correctly, there are recreated tide tables for the reef which show that the messages were sent at low tide, presumably so they could run the engine which would charge the batteries.  So my question is, has anyone looked at the possible effects of the tide heights on the Electra?  For example, when would the tide be high enough to flood the plane enough reach the batteries.  Would the empty gas tanks cause the tail of the plane to float?  Would the tides be high enough to float the plane off the reef?  I believe one of the messages indicated that water was up to their knees.  How high would that be, if they were in the cockpit, if they were in the navigation station?  If they were in the cockpit with water up to their knees, were the batteries submerged?  Sorry if this has been covered before, I'm new here.
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Greg Henton

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Re: Tides and the Electra
« Reply #1 on: November 06, 2011, 09:52:00 PM »

This is sort of a follow up post to my first—it sort of explains my uneasiness with the Gardner Island theory.

I find the TIGHAR explanation for AE/FN’s landing at Gardner Island both interesting and plausible, but I can’t shake some nagging doubts, oddly enough caused by the credible post loss radio messages.  The basic theory is that AE/FN landed the plane on the reef at Gardner Island, and stayed with the plane for several days, transmitting messages at low tide when they could run an engine to keep the planes batteries charged.  Plausible enough, but here are my problems with the theory:

1)   How likely is it that you could land a plane of a reef, injure both occupants of the plane, one of them seriously, yet have the plane sound enough to run one of the engines (i.e. the plane sitting properly on its landing gear, the engine mounts undamaged, the controls to it sound)?  It’s possible, but is it likely.

2)   The plane is a “tail dragger,” and from looking at the pictures, the cockpit is rather far off the ground when properly set on its landing gear.  Yet one of the post loss messages states that they were in water up to their knees, and the water was rising.  If they were in the cockpit of the plane, that would be pretty high water, and given the slant of the plane on its landing gear, much of the tail of the plane was either submerged, or floating, buoyed up by the empty gas tanks.  My understanding was that the radio was in the rear of the plane, under the navigator’s desk.  If the plane was on its landing gear, and the AE/FN in the cockpit with water up to their knees, then surely the radio, and possibly the batteries and engine carburetors were under salt water.  It’s hard to imagine that the radio would function in these conditions.

3)   But suppose that the rear of the plane is buoyed up by the empty gas tanks, and is sitting relatively horizontally, anchored by its main gear.  The water is still up to their knees, maybe 18 inches, and presumably the rest of the airplane is flooded to a similar depth.  If the radio is under the navigator’s desk, isn’t it still under water?

4)   But let’s assume that AE/FN are at the navigators station instead of the cockpit, then regardless of whether the tail wheel is on the ground or floating, they are still in water up to their knees, and the radio is still under the navigator’s desk.

So what does it mean?  I don’t know, it’s just problems that I have with the Gardner Island landing theory.
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richie conroy

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Re: Tides and the Electra
« Reply #2 on: November 07, 2011, 02:18:56 AM »

cant answer all ur questions because i have to go work but this should help u find some answers

http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/ArchivedBulletins.html

also from the evidence we have FN was possible injured when plane landed, and was stuck by navigators desk due to fuel tanks in fuselage, also the radio was in cockpit with amelia

if your really interested in the Gardner hypothesis, see Finding Amelia.
We are an echo of the past


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« Last Edit: November 07, 2011, 04:24:50 AM by Martin X. Moleski, SJ »
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Martin X. Moleski, SJ

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Re: Tides and the Electra
« Reply #3 on: November 07, 2011, 04:34:14 AM »

... Sorry if this has been covered before, I'm new here.

After three days of reading, it's fun for you to pepper the Forum with questions.

TIGHAR has been in the search-for-Amelia business since the two Toms pointed toward Niku in 1988.

The short answer to your question is, "Yes, people have thought about these issues during the last 23 years."  They have even written extensively about these issues.  A great deal of that writing is already available on the website.

You can (and should) search the website to see how much you can learn about TIGHAR's research.

Then, if you have a question about a particular claim made on a particular page, please provide a link to the page or document that interests you.
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Phil T Martin

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Re: Tides and the Electra
« Reply #4 on: November 07, 2011, 05:48:27 AM »

Greg, your skepticism is based off your assumption that the message about water being knee high implied that it was that deep in the plane. I believe they meant it was knee high on the reef. If the plane was flooded to that depth they would not have been able to run the engine to charge the batteries to send the message, etc...
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Ric Gillespie

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Re: Tides and the Electra
« Reply #5 on: November 07, 2011, 05:57:55 AM »


Welcome to the Forum Greg.  Marty is right about searching the website before posing questions but you raise a couple of points that we might not have specifically addressed.

1)   How likely is it that you could land a plane of a reef, injure both occupants of the plane, one of them seriously, yet have the plane sound enough to run one of the engines (i.e. the plane sitting properly on its landing gear, the engine mounts undamaged, the controls to it sound)?  It’s possible, but is it likely.

TIGHAR's hypothesis is in no way contingent upon them being injured in the landing.  We don't know that either or both occupants were injured.  That's one possible interpretation of the phrases transcribed in Betty's Notebook.  If one or both was injured at the time Betty heard them - Monday, July 5 fits best - their injuries might easily have been sustained not in the landing but in traversing back and forth to shore across the reef in the three days since they arrived.  I've done it many times.  Especially in the areas closer to shore it's slippery, jagged and treacherous.  You use a stout walking stick and take it about the pace of someone using a walker.  I've also fallen on the coral.  I can show you the scars.

2)   The plane is a “tail dragger,” and from looking at the pictures, the cockpit is rather far off the ground when properly set on its landing gear.  Yet one of the post loss messages states that they were in water up to their knees, and the water was rising.

That's not quite right.  On the third page of Betty's Notebook she wrote "waters knee-deep - let me out." It was Betty's later recollection that this was the man (presumably Noonan) talking.  The transmitter was in the cabin but radio transmissions could only be made from the cockpit.  If the water in the cockpit was knee deep the transmitter was under water and no transmission was possible - so that can't be what was meant.  The most logical meaning is that he was referring to the water level on the reef outside.  Knee-deep water (ballpark 18 inches) around the airplane is not high enough to threaten the transmitter, but from where we think the plane was you can only get to the shore with any semblance of safety at low tide.  On the morning of July 5 at Gardner Island, at the time Betty heard the transmissions, the tide was low but rising.  If the water outside the airplane was knee-deep it was already marginal for wading to shore (a Black Tip Reef Shark can swim in knee-deep water just fine).  On the last page of notes Betty wrote, "knee deep over" which she attributes to AE.  Knee deep over what?  Betty didn't catch the rest of it, but it seems to be a reference to the water depth over some particular part of the reef.   In any event, "knee-deep" can not refer to the water level in the plane.

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Ric Gillespie

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Re: Tides and the Electra
« Reply #6 on: November 07, 2011, 09:24:40 AM »

As for thinking the AE and FN were injured in the landing, that was based on the notes from Mabel Larremore's signal report and I just assumed that it implied they were injured during landing.

Mabel's report was quite early so it could be argued that it's more likely that the injury she mentioned occurred in the landing.  As to the likelihood of Fred banging his head in a rough landing or abrupt stop, we've noted that the plane was equipped with lap belts but not shoulder restraints.  There is also some reason to believe that the co-pilot side control wheel had been removed to give Fred more room.  A photo taken in Darwin, Australia shows a pile of gear, including a control wheel, beside the door of the plane. With no shoulder restraint and nothing to brace against, an abrupt stop might invite a close encounter with the instrument panel.

As for the tides, I could find information about the low tides (Bandenburg/TidalStudy/PLSigStatsandTide.pdf), but not high tides.  Is there a reconstructed tide graph for the period on the site and has that data been graphically illustrated on the reef flat diagram?

Funny you should ask.  We have a set of tide charts for the reef from July 2 to July 9 with the credible post loss signals overlaid. We're presently coding them up for publication on the TIGHAR website.  Get a good grip on your socks.
« Last Edit: November 07, 2011, 10:05:03 AM by Martin X. Moleski, SJ »
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Dan Swift

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Re: Tides and the Electra
« Reply #7 on: November 07, 2011, 02:39:12 PM »

As for knee deep water being difficult to traverse, especially on slick sharp coral, especially with surf moving in and out, especially with sharks having no difficulty swimming in it, especially if you were tired and hurt, but wouldn't it also disrupt the ability of the belly radio antenna (even if repaired after landing)?  Knee deep water could get to it very easlily?  Or, is there speculation that they figured out how to transmit over the other (top) antenna, which unfortunately (I believe) was always available...even in flight near Howland? 
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Ric Gillespie

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Re: Tides and the Electra
« Reply #8 on: November 08, 2011, 06:14:16 AM »

As for knee deep water being difficult to traverse, especially on slick sharp coral, especially with surf moving in and out, especially with sharks having no difficulty swimming in it, especially if you were tired and hurt, but wouldn't it also disrupt the ability of the belly radio antenna (even if repaired after landing)?  Knee deep water could get to it very easlily?  Or, is there speculation that they figured out how to transmit over the other (top) antenna, which unfortunately (I believe) was always available...even in flight near Howland?

There were three antennas on the airplane - a wire antenna that ran along the starboard side of the belly (we'll call this the "belly wire"), a vee that ran from a mast behind the cockpit to each of the two vertical stabilizers (we'll call this the "dorsal vee"), and a Bendix loop antenna over the cockpit (we'll call this the "loop").  The exact function of each antenna is not specified in the surviving records and has been the subject of much speculation, debate, and the occasional throwing of furniture.  Anything I say about them will include the phrase "seems to have been" meaning "seem to TIGHAR to have been."  As Marty likes to say, your mileage may vary.

The belly wire seems to have been a receiving antenna. Photos show that the lead-in went to where the Western Electric 20B receiver was installed under the co-pilot's seat. There is strong photographic evidence that the belly wire was lost during the takeoff form Lae.

The dorsal vee seems to have been a dedicated transmitting antenna. The lead-in went to where the Western Electric 13C transmitter was installed in the cabin behind the fuselage fuel tanks.  The WE 13C had the capability of sharing an antenna with a receiver but there is at least one photo showing that the terminal for the cable to the transmitter was not used.

The loop was a manually rotatable direction finding antenna and seem to have been attached to the WE 20B receiver via a "loop coupler."

Now to your question:
It is difficult to imagine how AE and FN could have repaired the belly wire.  The entire assembly - wire and supporting masts - seems to have been ripped off during the takeoff from Lae and, as you say, water could get to any wire along the belly - so I think we can safely eliminate the belly wire.

They didn't have to figure out how to transmit using the dorsal vee.  That's what it was for.

The loop was a receiving antenna- a specialized one to be sure, but a receiving antenna nonetheless.  Upon seeing that the belly wire was gone (Aha! That's why we couldn't hear Itasca's voice transmissions!") they could have used the loop to listen for signals from Itasca or monitor the powerful commercial stations in Hawaii - KGU and  KGMB - with which they were well-familiar from earlier flights to Hawaii.

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Dan Swift

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Re: Tides and the Electra
« Reply #9 on: November 08, 2011, 07:28:51 AM »

I know 'we' hate speculation, but they must have continued transmissions with just hopes that someone could hear them....since they were not sure or knew by then there was no way to recieve....or so they thought. 
Thanks for the clear explanation on the antennas. 
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Ric Gillespie

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Re: Tides and the Electra
« Reply #10 on: November 08, 2011, 07:36:46 AM »

I know 'we' hate speculation, but they must have continued transmissions with just hopes that someone could hear them....since they were not sure or knew by then there was no way to recieve....or so they thought. 

If you examine the Post-Loss Radio Signals Catalog you'll find that there is quite a bit if evidence to suggest that they were able to hear and respond to attempts to contact them.
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Greg Henton

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Re: Tides and the Electra
« Reply #11 on: November 09, 2011, 09:30:57 AM »

As I have been thinking about the tides and the electra, I began wondering if the tides were ever high enough to float the electra off the reef.  I turns out that this subject has been pretty well covered in the “ditching at sea” thread with the main arguments that it broke up on the reef (Ric Gillispe) and that it could have floated off (Gary LaPook).  Is the possibility that the plane floated off the reef be something that could be theoretically assessed?  After all, the locations of the fuel tanks are known, a reasonable estimate of the weight of the plane is available, and there is an estimate of the tides on the reef for the period in question.  Wouldn’t it be possible to estimate the amount of buoyancy provided by the fuel tanks for any given height of sea water?  If the tides never approached that level, it would support the hypothesis that the electra broke up in place, if the tides were high enough, maybe it did float off.
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Ric Gillespie

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Re: Tides and the Electra
« Reply #12 on: November 09, 2011, 09:46:46 AM »

As I have been thinking about the tides and the electra, I began wondering if the tides were ever high enough to float the electra off the reef.  I turns out that this subject has been pretty well covered in the “ditching at sea” thread with the main arguments that it broke up on the reef (Ric Gillispe) and that it could have floated off (Gary LaPook).  Is the possibility that the plane floated off the reef be something that could be theoretically assessed?  After all, the locations of the fuel tanks are known, a reasonable estimate of the weight of the plane is available, and there is an estimate of the tides on the reef for the period in question.  Wouldn’t it be possible to estimate the amount of buoyancy provided by the fuel tanks for any given height of sea water?  If the tides never approached that level, it would support the hypothesis that the electra broke up in place, if the tides were high enough, maybe it did float off.

Greg, keep reading.  The questions you pose have been hammered to death in the "Ditching at Sea" thread.  I've made the case that the plane broke up either on the reef or from being bashed against the reef by the surf after it went over the edge.  Gary believes if it went over the edge it would have floated away.  No one knows.  There is only one way to find out - go look.  That's what we plan to do.
« Last Edit: November 09, 2011, 10:06:33 AM by Martin X. Moleski, SJ »
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Michael Frazier

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Re: Tides and the Electra
« Reply #13 on: November 11, 2011, 05:13:47 AM »

The exact function of each antenna is not specified in the surviving records and has been the subject of much speculation, debate, and the occasional throwing of furniture.

I don't know anything about airplanes back in 1937 but I'm asking myself whether they got delivered
with a reasonable setup of antennas or not. If so, in my opinion it takes a pretty good reason to deviate
from this. Was it common to mess around with ones avionics then?

Michael
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Ric Gillespie

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Re: Tides and the Electra
« Reply #14 on: November 11, 2011, 06:40:25 AM »

Was it common to mess around with ones avionics then?

In 1937 the term "avionics" had not even been coined.  Most private aircraft had no radios at all.  Commercial aircraft usually had a transmitter and a receiver and a radio direction finder (RDF).  Aircraft were not delivered with a reasonable set up of antennas.  It was up to the buyer to spec out what was desired.  Earhart's Electra was purchased with money raised by Purdue University's "Amelia Earhart Aeronautical Research Foundation" and was supposed to be a "flying laboratory."  Hence the parade of changes to the aircraft's radio and fuel systems throughout its short career.
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