Monday, March 9, 2020

Is 2-2-V-1 a Piece of the Sydney Island Wreck? Update #5

In my last post I mentioned that I was unable find any measurement data on TIGHAR’s web site corroborating TIGHAR’s often-made claim that 2-2-V-1 is piece of .032 inch thick of 24ST aluminum sheeting. Ric Gillespie recently remarked on TIGHAR’s online forum that three sources had examined 2-2-V-1 and found it to be .032 inches thick [1].  When I checked reports these sources had submitted to TIGHAR [2,3,4], however, I couldn’t verify that what Gillespie said was actually true. Some of the reports do say that 2-2-V-1 is .032 inches thick, but they seem to be restating the thickness value reported by TIGHAR rather than reporting their own measurement results.

A long-time TIGHAR observer who read my post pointed me to a document on the TIGHAR web site that does provide an actual thickness measurement for 2-2-V-1. In 2015, Lehigh Testing Laboratories in New Castle, Delaware performed chemical and mechanical tests on several specimens of aluminum sheet submitted by TIGHAR, including a specimen cut from 2-2-V-1 [5]. A table on page five of the report listing the measured dimensions of each specimen reports that the 2-2-V-1 specimen was found to be .030 inches thick.

This measurement result raises the possibility that 2-2-V-1 is not a piece of .032 inch 24ST aluminum sheet as TIGHAR has long supposed it to be, but instead that it is a piece of .028 inch 24ST aluminum sheet. Note that I’m talking here about nominal thicknesses, not actual thicknesses, of aluminum sheeting. As discussed in my last post, at the time that artifact 2-2-V-1 was produced the thickness tolerances for Alclad 24ST sheet were .0025 inches for both nominal thicknesses, .028 and .032 inches. This means that nominal .028 inch 24ST aluminum sheet manufactured back then might actually be as much as .0305 inches thick, and nominal .032 inch 24ST aluminum sheet might be as little as .0295 inches thick. A thickness of .030 inches falls within the acceptable ranges for both nominal thicknesses and so it isn’t possible to know from this one measurement whether 2-2-V-1 was fabricated from a piece of .028 inch or .032 inch aluminum sheet.

The same person who pointed me to the Lehigh Laboratories thickness measurement pointed me to a thread on TIGHAR’s online discussion forum, excerpted below, in which Ric Gillespie reported his own thickness measurement results for 2-2-V-1 [6].  This part of the discussion was prompted by TIGHAR’s announcement that Lehigh Testing Laboratories would be analyzing specimens from 2-2-V-1.

TIGHAR announcement quoted by forum member Lehigh Testing Laboratories, Inc. was recommended to TIGHAR by Prof. Eager at MIT as the best lab for trying to learn more about 2-2-V-1 (and other aluminum artifacts) through materials analysis.  By pure coincidence, LTL is located in Wilmington Delaware about 45 minutes from TIGHAR HQ. I contacted LTL and dropped Tom Eagar's name.  They responded with enthusiasm and today we set out a program of testing that should give us the answers to a number of important questions.  Those answers could confirm our fondest conclusions about 2-2-V-1 or they could blow them out of the water... I won't try to list the alphabet soup of technologies LTL will be using to do this work.   They're doing this pro bono because such is TIGHAR's reputation in the scientific community that they consider it an honor to be asked to help with our investigation. What they'll be doing represents thousands, perhaps tens of thousands, of dollars worth of work if hired at commercial rates.  The results we'll get will be scientifically sound, whether or not they're what we want to hear.

Forum Member:  Would it be possible to have LTL confirm the gauge of the aluminum?  I believe the NTSB is the only one that measured it at .032, and I think at least one of their other measurements was slightly off (the convergence of the rivet rows?).  It would be helpful to know for sure what the gauge is.  Just a suggestion.

Gillespie:  Your belief is in error. The thickness of the sheet has been checked many times by many people.  All it takes is a micrometer.

Forum Member:  Alas I have no micrometer at my disposal at the moment nor access to the piece and am therefore dependent upon the written reports of others in this regard.  Could you please direct me to a source(s) that describes and documents any of the many gauge measurements that were made (other than the NTSB report already mentioned), preferably one that includes a description of the tolerance levels involved.  Thank you.

Gillespie:  Okay.  Here's a written report especially for you. I have a micrometer and I have access to the piece and I have measured it numerous times. It's .032".  You can choose not to believe me and wait for the LTL report which will include much more detail.

Gillespie’s answer may be flippant, but it nevertheless contains some useful information. His belief that 2-2-V-1 is a piece of .032 inch 24ST aluminum sheet is based at least in part on multiple thickness measurements that he himself made using a micrometer. But remember what Gillespie said in questioning Tom Palshaw's micrometer skin thickness measurements on the NEAM C-47 wing [7]:

I know from experience that measuring skin thickness with a digital micrometer is difficult and frustrating.  Measure three times and get three different answers. With a little confirmation bias you can get any result you want.

Tom’s follow-up measurements made using an ultrasonic thickness gauge show that Tom’s original micrometer measurements were correct. I think it’s fair to ask whether Gillespie’s own thickness measurements on 2-2-V-1 might have suffered from confirmation bias. When Gillespie made his measurements, what sheet thicknesses did he think 2-2-V-1 might have been manufactured from? Current aluminum product catalogs like the one reproduced below don't list a sheet thickness between .025 and .032 inches for 2024-T3 Clad aluminum, the modern designation for 24ST Alclad. As discussed in my last post, Alcoa product literature from the early 1940s list .028 inches as an available thickness for Alclad 24ST sheet. Did Gillespie know that when he made his measurements? I wonder if Gillespie arrived at his firmly stated .032 inch thickness for 2-2-V-1 through the following process:

1. Gillespie measures 2-2-V-1’s thickness several times with a micrometer; his measurement results cluster around some value between .032 inches and .025 inches, but closer to the former value;
2. Gillespie knows that Alclad 2024 aluminum sheet is currently produced in nominal thicknesses of .025 and .032 inches but is unaware that decades earlier it was produced in a nominal sheet thickness of .028 inches;
3. Since Gillespie’s micrometer measurement results for 2-2-V-1 are closer to .032 inches than to .025 inches, he concludes that 2-2-V-1 is a piece of 24ST Alclad sheet of .032 inch nominal thickness.

Thyssennkrupp Aluminum Stock Guide [8]

If any readers out there know of TIGHAR data that convincingly settles the matter of whether 2-2-V-1 is a piece of nominal .028 inch of .032 inch aluminum sheet, please let me know where to find it. If there is no such data — and I suspect that there isn’t — TIGHAR needs to arrange to have quality measurements made to try to settle this question.  Tom Palshaw noted in his most recent report update that factors such as corrosion, shape, installed fastener effects, and stress induced changes to original dimensions would need to be carefully considered in making thickness measurements on a beaten up, weathered piece of aluminum sheet like 2-2-V-1, and so this is not a job for an amateur wielding a micrometer, with all due respect to Ric Gillespie.

Why is it important to accurately characterize 2-2-V-1’s thickness? Tom Palshaw has shown that 2-2-V-1’s rivet pattern matches the rivet pattern on the upper wing of a C-47 at the New England Air Museum (NEAM). It is reasonable to think that the rivet pattern match would extend to many other C-47s, including the C-47 that crashed on Sydney Island. Tom has confirmed through ultrasonic thickness gauge measurements that NEAM C-47 wing skin is .032 inches thick at the location of interest, the same thickness that TIGHAR has long reported for 2-2-V-1. C-47 repair manuals indicate that the skin of a C-47 should be .028 inches thick at the location of the rivet pattern match, and so it is not a sure thing that the Sydney Island C-47 would also have a seemingly non-standard .032 inch skin thickness at the matching location. On this basis Ric Gillespie can say that the rivet pattern match to the NEAM C-47 wing is a “crazy coincidence”,  and TIGHAR’s claim that 2-2-V-1 is a piece of Amelia Earhart’s Electra can perhaps limp along, badly wounded but not dead. But the .030 inch thickness value measured by Lehigh Testing Labs suggests that if 2-2-V-1 might really a piece of nominal .028 inch 24ST Alclad.  If careful thickness measurements show this to be true, there would be no reason left to think that 2-2-V-1 wasn’t a piece of the wing of the Sydney C-47 wreck. The match in rivet patterns between 2-2-V-1 and the NEAM C-47 wing makes it reasonable to think that the Sydney C-47 wing matched 2-2-V-1’s rivet pattern at the location of interest. If 2-2-V-1 is nominal .028 inch aluminum sheet then it matches the thickness for a C-47 wing at the matching location given in repair manuals. There would be no physical attribute of 2-2-V-1 that can't be matched to a C-47 wing. The claim that 2-2-V-1 is a piece of Amelia Earhart’s Electra would truly be dead.

Comments, corrections, additional relevant facts, differing viewpoints, etc., are welcome.  Send to
[2] (NTSB)
[3] (MMR)
[4] Letter from MIT Professor Thomas Eagar to Ric Gillespie
[5] The Lehigh Testing Laboratories Report can be downloaded at:

Friday, February 14, 2020

Is 2-2-V-1 Piece of the Sydney Island C-47 Wreck? Update #4

Since my last post on the topic of Tom Palshaw’s report, there have been new developments that are worth discussing. In a recent post on TIGHAR’s online discussion forum [1], Ric Gillespie rejected the report’s conclusion that TIGHAR Artifact 2-2-V-1 is a piece of the wing of a C-47 transport plane that crashed on Sydney Island. Gillespie writes:

TIGHAR Artifact 2-2-V-1 did not come from a C-47.  The Wing Plating diagram in the C-47 structural repair manual shows the skin thickness in the entire area where the rivet pattern allegedly matches 2-2-V-1 is .028".  The artifact's skin thickness is .032”

Tom Palshaw measured the skin thickness on the C-47B wing at the New England Air Museum as .032 using a micrometer at the edge of the skin.  .004" is an easy error to make. It's a small but important discrepancy.  The NTSB lab, Professor Eager at MIT, and the Massachusetts Materials Research metallurgical lab all measured 2-2-V-1 as .032”.

The C-47 manual dates from September 1942 and was updated in 1945.  There is no indication that the basic structural components of the wing were changed. With this new information, the rivet pattern on the C-47 wing, although remarkably similar to the artifact, becomes another of the crazy coincidences we sometimes encounter.

In response to this critique, Tom Palshaw has updated his report with new skin thickness measurements on the NEAM C-47 wing at the location of interest. These measurements were made by a level 2 nondestructive testing technician from Bombardier Business Aircraft Service Center using an ultrasonic thickness gauge. I take it that this technique is not prone to sort of errors that Ric Gillespie suggests might have afflicted Tom’s original measurements.  Five ultrasonic thickness gauge measurements yielded skin thicknesses of 0.032, 0.031, 0.032, 0.031, and 0.032 inches. These new measurements confirm that the skin of the NEAM C-47 wing at the location of interest is the same thickness that TIGHAR has reported for 2-2-V-1.

 Wing location matching 2-2-V-1 is marked in yellow (Markup by Palshaw of a DC-3 repair manual; See Ref. 8)

As Ric Gillespie points out, C-47 repair manuals indicate that the skin of the NEAM C-47 wing should be .028 inches thick at the location of interest. It isn’t clear why the NEAM C-47 wing’s skin at the location of interest is thicker than repair manuals indicate it should be. Damaged aircraft skin is often replaced with sheeting in the next higher thickness produced by manufacturers, which in this case would be .032 inches thick. Tom tells me he’s sure that at the location of interest the C-47 wing skin is original factory-installed Alclad 24ST aluminum alloy sheeting, not a later repair. For what it’s worth, I’ll note that .028 inch 24ST aluminum alloy sheeting is not listed as a standard size normally carried in stock in 48 inch widths in the Alcoa's Aluminum in Aircraft published in 1941.  Would sheeting of that width be needed for fabricating the skin at the location of interest on the C-47 wing? If so, perhaps this is a clue that should be pursued in understanding why the NEAM C-47 wing skin is .032 inches thick at the location of interest. Something else that suggests .028 inches is not your typical aluminum alloy sheet thickness: the 1943 version of Aluminum in Aircraft has only one mention of .028 inch aluminum -- in a table of sheer strengths of spot welds for various metal thicknesses

Aircraft sheet metal thickness table, Aluminum in Aircraft, Published by Alcoa in 1941

Spot weld shear strength table, Aluminum in Aircraft, Alcoa 1943

As things now stand, Tom Palshaw has shown that a location on the wing of the NEAM C-47 closely matches 2-2-V-1 in terms of rivet line spacing, rivet pitch, irregularities in pitch of its -5 rivets, and that it has the same .032 inch thickness that TIGHAR has reported for 2-2-V-1. The NEAM C-47 wing and 2-2-V-1 match in every physical attribute determined so far.  From the standpoint of physical dimensions the match between 2-2-V-1 and the NEAM C-47 wing has been better established than the match between 2-2-V-1 and Amelia Earhart’s Electra. As discussed in my last post, past TIGHAR efforts have failed to demonstrate that 2-2-V-1 fits within the boundaries TIGHAR defined for the putative source location on Earhart’s airplane, the window patch installed at Miami in 1937.

The letters ‘AD’ that are faintly visible on the artifact’s surface are another feature that is consistent with the idea that 2-2-V-1 is a piece of the Sydney Island C-47. To help factory workers identify aluminum sheet stock, Alcoa applied material markings to the aluminum sheeting it produced. The Aluminum Markings web site documents a clear trend in how Alcoa’s material markings for Alclad 24ST aluminum sheeting that aircraft skins are made of changed over time.  Photos of aircraft manufactured before 1942, including Amelia Earhart’s Lockheed Electra, consistently show the marking to be  ‘ALC 24ST’.  Photos of aircraft manufactured from 1942 onward predominantly show the marking to be  ‘ALCLAD 24 ST’, though some photos show aluminum aircraft parts marked ‘ALC 24ST’.  So the photographic evidence —a lot of it— indicates that by early 1942,  had Alcoa started to mark 24ST Alclad sheeting it manufactured with a new material marking, ‘ALCLAD 24ST’. This line of evidence therefore tells us that the window patch attached to Earhart’s Electra in Miami in 1937 could not have the letters ‘AD’ seen on 2-2-V-1 because because Alcoa didn’t start using the ‘ALCLAD 24 ST’ material marking for several more years.

Remnant of 'AD' on Artifact 2-2-V-1. See reference [5] for source

B-25 factory photo, circa 1942. Note 'ALCLAD 24S-T' markings to left of female worker

Underside of Earhart's Electra, circa 1937. The material marking reads 'ALC 24ST'. Full photo at upper right

The similarities between the NEAM C-47 wing and 2-2-V-1 are just too great to be dismissed as a ‘crazy coincidence’.  The problem with the assertion that the wing of the Sydney Island C-47’s can’t be the source of 2-2-V-1 because repair manuals indicate that skin at the location of interest shouldn’t be .032 inch thick is that an actual C-47 wing, the one at NEAM, shows that C-47 wings were not always manufactured with the skin thicknesses indicated in repair manuals.

The right thing for TIGHAR to do, given the evidence Tom Palshaw has produced, is gather evidence that might shed further light on the Tom’s conclusion that 2-2-V-1 is a piece of wreckage scavenged from the Sydney C-47. To misrepresent a piece of the Sydney C-47 wreck site as a piece of Amelia Earhart’s Lockheed Electra would be a disservice to those who died in the Sydney C-47 crash and to the crew of the Electra. Surely TIGHAR would want no part of such an abomination.

TIGHAR should carefully document how well the rivet pattern on the NEAM C-47 wing matches 2-2-V-1. Laying 2-2-V-1 over the NEAM wing at the location of interest and documenting the match with photographs would take no more than ten or fifteen minutes to do. While at NEAM to conduct this comparison, TIGHAR can also demonstrate whether or not 2-2-V-1 fits within the boundaries defined for the dimensions of the Miami window patch in a previous TIGHAR study [2]. This too would be a simple exercise that would only take minutes to carry out. These comparisons should be done with the full cooperation of Tom Palshaw. I find it odd that Ric Gillespie visited NEAM only a few weeks ago to conduct measurements on the NEAM Electra but gave Tom Palshaw no advanced notice of his visit.

Another basic piece of information that needs to be better documented is 2-2-V-1's thickness. Although TIGHAR has repeatedly stated that 2-2-V-1 is .032 inches thick, I can find no clear information about how 2-2-V-1’s thickness was determined. A few posts further along the discussion thread in which Ric Gillespie dismisses Sydney Island C-47 as the source of 2-2-V-1, he comments that “The NTSB lab, Professor Eager at MIT, and the Massachusetts Materials Research metallurgical lab all measured 2-2-V-1 as .032” [3]. I’ve reviewed all three of these sources [4,5,6] and as best I can tell, 2-2-V-1’s thickness was not actually measured by NTSB, MIT or the metallurgical lab. Where the thickness of 2-2-V-1 is stated in these sources the authors appear to simply be stating the artifact thickness reported to them by TIGHAR. There certainly is no description in any of these sources of a measurement method or a presentation of actual measurement data.

Surely the 0.32 inch thickness TIGHAR has reported is based on an actual measurement, but how that measurement was made and what the actual measurement result was has never been reported, as far as I know. Did Ric Gillespie make these measurements using a micrometer? If so, then the claim that 2-2-V-1 is .032 inches thick is based on the same measurement technique that Ric Gillespie has said could easily be in error by .004 inches. Gillespie in a later post on the same TIGHAR discussion forum states: “I know from experience that measuring skin thickness with a digital micrometer is difficult and frustrating.  Measure three times and get three different answers. With a little confirmation bias you can get any result you want” [7]. Here it is worth quoting something Tom wrote in his latest update on the NEAM C-47 skin thickness measurements:

Measuring the thickness of a new sheet of ALCLAD is as simple as using a standard 1" micrometer. The metal is smooth, flat, and clean. Once the metal has been installed, or exposed to the elements, several factors can affect the accuracy of the measurement. These include a paint coating, corrosion, shape, installed fastener effects and stress induced changes to its original dimensions.

2-2-V-1 is not a fresh new sheet of aluminum alloy, it is a beaten up sheet of aluminum alloy that undoubtedly has been exposed to the elements for many years. The Massachusetts Materials Research Laboratory report on 2-2-V-1 describes it thusly:

Overall, the artifact presented a grey, oxidized aluminum appearance with isolated regions of buff-colored calcareous deposits and thin, green discolorations. Both the buff and green deposits were reported to have been previously tested and found to be consistent with coral and algal growths

Note that before making his new measurements on the C-47 wing, Tom gently removed accumulated surface coatings from his measurement locations using a Scotchbrite pad. Were surface deposits accumulated in the years of exposure of 2-2-V-1 to the elements removed before its thickness was measured? Tom points out that at the time artifact 2-2-V-1 was produced, the thickness tolerances for Alclad 24ST sheet was .0025 inches for manufactured sheeting in either the .028 or .032 inch thickness. For all we know, 2-2-V-1’s actual thickness falls within the range falls within the range for nominal .028 inch sheeting, but TIGHAR has erroneously reported it to be .032 inches thick. For example, if 2-2-V-1 was nominal .028 inch sheeting whose actual manufactured thickness was .029 (well within the manufacturing tolerance) with a .001 inch thick coating of weathering/coral/algal residue, and a .001 inch micrometer measurement error was made, the measured thickness would have been .031 inches (.029+.001+.001=.031). The individual making the measurement might have  concluded that 2-2-V-1 was .032 inch thick since this was the closest nominal Alclad 24ST sheet thickness to the measurement result.

Clearly then another thing TIGHAR must do is document what 2-2-V-1’s thickness was when manufactured. Given the .0025 inch manufacturing tolerance, it may not be possible to definitively exclude that 2-2-V-1 was either nominal product thickness, .028 or .032 inches. The determination of 2-2-V-1’s original manufactured thickness is yet another activity that TIGHAR could and should carry out in collaboration with Tom Palshaw. The effects of factors Tom mentions in his update such as shape, installed fastener effects, and stress induced changes to original dimensions would need to be carefully considered.

It would also be useful to accumulate more information about rivet patterns and skin thicknesses of surviving C-47s and DC-3s in museum and private collections. Tom’s update includes ultrasonic measurements of the thickness of the skin of the NEAM DC-3 at the location of interest [8], and there the measurements indicated a skin made of .028 inch nominal sheeting. Accurate skin thickness measurements made on other C-47s and DC-3s might reveal a pattern relevant to the question of whether the Sydney C-47 is the source of 2-2-V-1.

Comments, corrections, additional relevant facts, differing viewpoints, etc., are always welcome.  Send to

[2] Earhart Project Research Bulletin #73, The Window, the Patch, and the Artifact.
[3] See the TIGHAR discussion forum post at reference 1
[6] Links to the MIT emails can be found at
[7] [,2074.msg43575.html#msg43575]
[8] DC-3s and C-47s are to a great extent the same airplane, the former manufactured for use as a civilian airliner while the latter was made to be a military transport. The wing diagram above comes from a 1940s-vintage DC-3 repair manual

Thursday, January 2, 2020

Is 2-2-V-1 Piece of the Sydney Island C-47 Wreck? Update #3

The latest notable response to Tom Palshaw's report is a post on the TIGHAR discussion forum by Ric Gillespie reporting new rivet line spacing measurements for 2-2-V-1 [1]. According to Gillespie:

 “The differences, while not huge (see “Actual v template”.jpg ) are significant when measuring precise alignment with the pattern on the C-47 wing. Palshaw’s template appears to fit the C-47B wing but it does not accurately reflect the artifact.

The ‘Actual v. template’ figure (see below) is Gillespie’s markup of a photo in the Palshaw report showing a paper template of 2-2-V-1 laid over the New England Air Museum (NEAM)  C-47 wing. The lines on the template were made by Tom Palshaw to indicate 2-2-V-1’s rivet line spacings based on earlier TIGHAR data. The numbers in yellow were added by Ric Gillespie to indicate his new rivet line spacings. I’ve further marked up the photo with the numbers in blue to correct errors in two of Gillespie’s numbers.

Gillespie's new rivet line spacing measurements superimposed on Tom Palshaw's  2-2-V-1 template.
The differences between the new rivet line spacings and those in Tom Palshaw’s template are small, as Gillespie notes. Do these differences matter with regard to the question of whether 2-2-V-1’s rivet lines match those of the NEAM C-47 wing? Tom’s template was a stand-in for 2-2-V-1, which he didn’t have access to when he wrote his report. Rather than concerning ourselves with Tom’s template, let’s consider how well the thing itself, 2-2-V-1, matches the wing. The photo below is a screen shot from the YouTube video of Gillespie and Palshaw comparing 2-2-V-1 to the NEAM C-47 wing in 2017 [2]. At the edge of 2-2-V-1 closest to the camera 2-2-V-1’s rivet hole lines appear align well with those on the underlying C-47 wing. Gillespie’s new measurements don’t appear to disqualify the NEAM C-47 wing as a match for 2-2-V-1, at least at the side closest to the camera. The YouTube video does not provide as good a view of the far end of 2-2-V-1, but neither Gillespie or Palshaw say in the video that the rivet line spacings of the C-47 wing and 2-2-V-1 don’t match.

Direct comparison of 2-2-V-1 to the NEAM C-47 wing

Further along in the same TIGHAR forum post in which Ric Gillespie reports his new rivet line spacing measurements, he writes:

For the best possible comparison to the C-47A that crashed on Sydney Island, we need to come as close as we can to apples-to-apples. We need to do a detailed examination and measurement of the relevant section on the wing of the closest surviving C-47A by tail number.  We will be doing that later this winter.

While it would be interesting to see how well 2-2-V-1 matches the wings of other C-47s, surely a careful examination of the NEAM C-47 wing should take precedence over comparisons to other C-47s. All information available so far indicates that the NEAM C-47 wing is a close match to 2-2-V-1. The doubts Gillespie raised in the YouTube video were addressed in the Palshaw report, and since then Tom has found additional matching features, as discussed in my earlier posts. TIGHAR should collaborate with Tom Palshaw to carefully compare 2-2-V-1 to the NEAM C-47 wing to determine just how well they match. Ric Gillespie has written that “TIGHAR is an educational foundation and the Earhart mystery is a perfect vehicle for exploring, demonstrating, and teaching the scientific method of inquiry” [3]. The scientific method of inquiry most definitely is not about ignoring observations that suggest a favored hypothesis is wrong.

If we are to believe that 2-2-V-1 came from the Sydney Island C-47 wreck, it is reasonable to expect proof that 2-2-V-1 matches some part of a C-47.  Likewise, if we are to believe that 2-2-V-1 is a piece of Amelia Earhart’s Lockheed Electra it is reasonable to expect that TIGHAR demonstrate that  2-2-V-1 corresponds to a source location on Earhart’s Electra. According to TIGHAR, that source location is the ‘Miami Patch’, an aluminum alloy sheet that was attached to Earhart’s Electra in Miami to cover a window early on the voyage on which she disappeared. In the photo below taken shortly after it was installed, the shiny new Miami Patch stands out from the more weathered fuselage to which it had been attached.

The newly-installed window patch. Miami, June 1937.

A basic requirement for 2-2-V-1 to be a piece of the Miami Patch is that it must be smaller than the Miami Patch. This is necessarily true because nowhere on 2-2-V-1 is there an original manufactured edge; 2-2-V-1 was clearly torn away from a larger piece of aircraft skin. TIGHAR has stated that 2-2-V-1 fits within the perimeter of the Miami Patch but as far as I know it has never published a photo demonstrating this to be the case. One place where TIGHAR states that 2-2-V-1 fits within perimeter of the Miami Patch is in TIGHAR Research Bulletin #72 [4]. A section titled ‘Do the dimensions of the artifact fit within the dimensions of the patch?’ states:

To answer that question required accurate scaling and the removal of camera-induced distortion from the Miami Herald photo and a photo of 2-2-V-1 pressed down to allow measurement of its full size.  The edges of the patch were straight and riveted, while the borders of the artifact are all failed edges, with one side showing evidence of a line of staggered rivets. If the artifact is a broken-out portion of the patch it must fit within the dimensions of the patch. TIGHAR forensic imaging scientist Jeff Glickman was able to remove the distortion and accurately scale and overlay the photos. The artifact fits nicely within the patch.

The accompanying image of the overlay, see below, does indeed depict 2-2-V-1 as nicely fitting within the boundaries of the Miami Patch. Given 2-2-V-1’s size, the overlay suggests that 2-2-V-1 is several inches smaller than the Miami Patch both vertically and horizontally.

But this overlay must be in error, because actual photos of 2-2-V-1 held close to surviving Lockheed Model 10 Electras show that if 2-2-V-1 fits within the Miami Patch’s boundaries at all, it does so with very little room to spare. TIGHAR Research Bulletin #73 [5] reports the results of an examination of an Electra undergoing restoration in Wichita, Kansas. The report includes the photo below of 2-2-V-1 held close to the exterior of the Wichita Electra’s fuselage, with the perimeter of the Miami Patch outlined somewhat inaccurately with yellow adhesive measuring tape. 2-2-V-1 does not appear to fit within the marked boundaries of the Miami Patch. The ‘Tab’ feature at the bottom edge of 2-2-V-1 extends below the lower boundary of the Miami Patch, which in this photo corresponds to the upper edge of the yellow tape. 2-2-V-1 also overlaps the yellow tape that marks the forward perimeter of the Miami Patch, which in this photo is placed too far forward. As discussed in TIGHAR Research Bulletin #73 itself, the forward edge of the patch had to be tailward of where it appears in the photo [6]. 2-2-V-1 fits within the upper perimeter of the patch, but perhaps only because as 2-2-V-1 is held in this photo it bulges outward, which lessens any vertical mismatch between it and the patch. Remember that since 2-2-V-1 is a remnant of a larger piece of metal, it must not only fit within the perimeter of the patch, it must do so with room to spare. TIGHAR Research Bulletin #73 notes the lack of fit apparent in this photo and explains it as being an effect of perspective, i.e., 2-2-V-1 appears to be larger relative to the fuselage than it really is because it’s slightly closer to the camera. Why this report did not include a photo of 2-2-V-1 pressed against the side of the Wichita Electra to clearly show how well it fits within the required perimeter is a mystery; surely a thin sheet of transparent plastic could have been placed between fuselage and 2-2-V-1 to prevent cosmetic damage to the surface of the airplane if that was a concern.

2-2-V-1 compared to the Miami patch perimeter, Wichita.

If TIGHAR has a photo from the Wichita exercise that properly compares 2-2-V-1 to the Miami Patch’s perimeter, it should publish that photo to support its claim that 2-2-V-1 is a piece of the Miami Patch. If TIGHAR does not have such a photo, it is all the more reason to return to NEAM. NEAM has a Lockheed Model 10 Electra in its collection, so in addition to documenting how well 2-2-V-1 matches the NEAM C-47 wing, TIGHAR can document how well 2-2-V-1 fits within the boundaries of the Miami Patch.

Some time ago Ric Gillespie posted a photo on the TIGHAR Forum similar in composition to the Wichita photo, but using the NEAM Electra's fuselage as the backdrop and the patch perimeter marked with clear adhesive tape.  That photo (see below) shares some of the Wichita photo’s problems, e.g., the forward perimeter is placed too far forward and 2-2-V-1 bulges outward. Additionally, 2-2-V-1 is held at an unlikely angle with respect to the Electra’s fuselage; the lowest rivet line would not span the width of the patch at the angle it makes with the lower boundary of the patch. Gillespie notes some of these problems, but his assessment was nevertheless that "It's not a great photo and the placement is a bit too high and a tad too far forward on the airplane but, as you can see, it all works". But it doesn't all work. 2-2-V-1 extends beyond the upper and lower perimeter of the patch even though its outward bulge reduces the extent of the overlap, and since the forward perimeter is too far forward, it is not clear that 2-2-V-1 is fits horizontally within the Miami Patch's boundaries. Once again I note that 2-2-V-1 must fit with room to spare since it is a fragment of a larger piece of metal.

2-2-V-1 compared to the Miami Patch perimeter, New England Air Museum

TIGHAR claims that 2-2-V-1 is small enough to be a piece of the Miami Patch, but it hasn’t provided clear photographic proof that this is true. It should take less than an hour at NEAM to properly compose a comparison photo that would provide this needed proof. The four borders of the patch perimeter would need to be properly positioned on the fuselage and 2-2-V-1 would need to be pressed against the NEAM Electra's fuselage to minimize bulges and to eliminate effects of perspective.

Comments, corrections, additional relevant facts, differing viewpoints, etc., are always welcome.  Send to

[6] In the Wichita photo, the forwaed perimeter coincides with a row of staggered rivets at what is referred to as 'Station 293 5/8'.  TIGHAR Research Bulletin #73 states: "The frame could not be riveted directly to the underlying structure at Sta. 293 5/8 because of the thick lavatory bulkhead on the interior (no way to buck the rivets), so new underlying structure was added just aft of Sta. 293 5/8 to provide something to rivet the frame to".

Wednesday, December 11, 2019

Is 2-2-V-1 Piece of the Sydney Island C-47 Wreck? Update #2

Tom Palshaw’s report that TIGHAR Artifact 2-2-V-1 matches a section of the upper wing of a C-47 transport plane has elicited some interesting responses at TIGHAR’s discussion forum. A TIGHAR member stated that Tom had made a good case that a C-47 wing was the source of TIGHAR artifact 2-2-V-1 but suggested that Tom should further document his findings. He also suggested that Tom provide photographic evidence of C-47 wing features, such as the spacing between rows of rivets and the rivet pitch, i.e., the distance between rivets in each row. This led Ric Gillespie to make a post on the forum, the key points of which I’ll quote below:

If 2-2-V-1 is from the wing of a C-47, all aspects of the artifact must match. Beyond row spacing and pitch, the following must also match:

• Rivet size (shaft diameter):
The rivet on 2-2-V-1 has a shaft diameter of 3/32 inch - source NTSB Laboratory.

• Rivet length (shaft length):
The rivet on 2-2-V-1 has a shaft length of 3/16 inch - source NTSB Laboratory.

• Rivet material:
The rivet on 2-2-V-1 has a dimple in the center of the head, signifying it is made of A17ST alloy - source "Aircraft Maintenance and Repair" Northrop Aeronautical Institute, 1955. See attached PDF of rivet coding.

• Rivet head type:
The rivet on 2-2-V-1 is a "brazier" head. A brazier head rivet has a low profile, minimizing drag. There are two kinds of brazier head rivets,  the "full brazier head" and the "modified brazier head".  As early as 1930 and as late as 1941and possibly later, the "modified brazier head" was known as the "mushroom head."  The rivet on 2-2-V-1 is what is now known as a "full brazier head" rivet. Lockheed Electras had dimpled "full brazier head rivets" identical to the rivet on 2-2-V-1.  See photo below.

• Sheet thickness
The 2-2-V-1 sheet has a thickness of 0.032" - Source NTSB Laboratory

Tom saw these comments and in response wrote a detailed explanation of how various measurements he made were done. This additional information now appears in Tom’s report as Appendix II.

In this post, I’ll provide what I hope is a summary of Tom's Appendix II that will be helpful to layman like me out there who are following the 2-2-V-1 story. I’ll also provide additional information on how 2-2-V-1 appears to match the NEAM C-47 wing that Tom only became aware of after his report was published online.

The first bullet item is about rivet shaft diameter.  During Gillespie and Palshaw’s joint examination of the NEAM C-47 wing, Ric Gillespie questioned whether certain rivets were -4 rivets rather than -3 rivets. One of the main points Tom makes in his report is that the rivets in question are indeed -3 rivets. Appendix II of Tom’s report explains how  this was determined. Tom removed a rivet from the C-47 wing and inserted a drill that matched the rivet hole. This was a number 40 drill, the recommended drill size for -3 rivet holes. The matching drill for a -4 rivet hole is a number 30 drill, which does not fit into a -3 rivet hole. Tom provided a table from the Canadair Challenger Structural Repair Manual (1981), 51-42-11, page 6, figure 4, reproduced below, showing the correspondence between drill numbers and rivet hole sizes. Tom verified the -5 rivets on the C-47 wing using this same drill matching method.

Interested readers can check the photo below to see where Tom removed -3 rand -5 rivet removed from the C-47 wing to verify their sizes.

The second bullet item about rivet length states: “The rivet on 2-2-V-1 has a shaft length of 3/16 inch - source NTSB Laboratory.” I checked the NTSB report on TIGHAR’s web site [1] but see nothing there about rivet shaft length, so I will set this bullet item aside.

The third bullet item is about rivet material. Gillespie states:

“The rivet on 2-2-V-1 has a dimple in the center of the head, signifying it is made of A17ST alloy”

The photos included in Tom’s report aren’t sharp enough to show whether the rivet heads have dimples, so I asked Tom about the rivet heads, and he confirmed that they do in fact have dimples. He sent me the photo below of -3 rivets on the C-47 wing that demonstrates this to be the case. The ruler laid alongside the -3 rivets makes clear that the 1 inch pitch of the -3 rivets. Thus, in terms of the material type and rivet pitch the NEAM C-47 wing matches TIGHAR artifact 2-2-V-1.

The fourth bullet item about rivet head type states that the one -3 rivet still attached to 2-2-V-1 is a brazier head rivet. The Matching Characteristics section of Tom’s report states that the  C-47 wing -3 rivets are also brazier head rivets. Tom confirmed in an email exchange with me that that the C-47 wing -3 rivets are brazier head rivets, not modified brazier head rivets.  The table below indicates that -3 brazier head rivets and -3 modified brazier head rivets have quite different head diameters and so can be readily distinguished from one another based on their size. Readers can check the photo above against the table below to confirm that diameter of the -3 rivet heads on the C-47 wing are correct for -3 brazier head rivets, not modified brazier head rivets.

Gillespie’s fifth bullet item concerns sheet thickness.  The ALCLAD sheet that 2-2-V-1 is made of is 0.032 inches thick. The ‘What on Artifact 2-2-V-1 Matches the Wing of a C-47B?’ section of Tom’s report states that the thickness of the NEAM C-47 wing in the area of interest is also .032 inches. The excerpt below from Appendix II of Tom’s report states:

To determine the grip length it was necessary to first measure the skin thickness. This was done by using a micrometer at the edge of the skin. To measure the grip length a "calibrated" cleco was used to compare a known stack up of aluminum to that of the wing. The result was a skin thickness of 0.032" and a stringer thickness of 0.060". This is similar to the NTSB Report.

Some of this is a little over the head of a layman like me, but what’s clear is that Tom determined the 0.032 inch skin thickness of the NEAM C-47 wing skin in the area of interest by using a micrometer to measure the skin edge.  Note also that in the above excerpt Tom points out another matching point between the C-47 wing and 2-2-V-1: in both cases, the underlying stringer the skin is attached to was 0.060 inches thick.

That is my layman’s summary of Tom Palshaw’s Appendix II.

I also mentioned that after Tom’s report was published he realized that there was yet another way in which the C-47 wing and 2-2-V-1 match. This new information has to do with 2-2-V-1’s ‘Tab’ feature. A line of –5 rivet holes runs along one edge of 2-2-V-1, and a ‘Tab’ of material juts out from that same edge (see photos below).  At the far edge of the ‘Tab’ are what appear to be partial holes of another line of rivets. I sent Tom a close-up photo of the Tab with measuring tape laid over it (see photos below) that indicates a 1 5/16 inch spacing between 2-2-V-1’s line of -5 rivets and the rivet line at the far edge of the Tab. On the NEAM C-47 wing the line of -5 rivets that corresponds to the -5 rivet line on 2-2-v-1 has a line of -6 rivets running adjacent to it, separated by 1 5/16 inches (see photo below). Thus, the spacing between these two rivet lines on the C-47 wing matches the spacing of the rivet lines seen on 2-2-V-1's Tab. Tom thinks the partial rivet holes on the Tab’s edge are for size -6 rivets, but none of the holes is complete, so this is unclear.

2-2-V-1. The Tab is at the lower edge. The line of -5 rivet holes runs across the lower edge of 2-2-V1 and through the Tab

Spacing between rivet hole lines on the Tab

Spacing between -5 and -6 rivet hole lines on the NEAM C-47

Ric Gillespie's remark that the C-47 wing is "not even close" to a match for 2-2-V-1, as he put it, just does not seem to hold up, given what Tom Palshaw has reported.  If clearer documentation of the C-47 wing's features are needed, I think Ric Gillespie knows how to obtain it.

Comments, corrections, additional relevant facts, differing viewpoints, etc., are always welcome.  Send to

Wednesday, December 4, 2019

Is 2-2-V-1 a Piece of the Sydney Island C-47 Wreck? An Update.

Two days ago I published a short post on Tom Palshaw’s report matching TIGHAR artifact 2-2-V-1 to the upper section of the wing of a C-47 in storage at the New England Air Museum (NEAM). Ric Gillespie had recently stated on the TIGHAR Forum that he had examined the NEAM C-47 wing and found it to be “not even close” to a match to 2-2-V-1, but he offered no specifics to back up this assessment.  I thought Tom had made a good case for 2-2-V-1 being a scavenged piece of the Sydney C-47 worthy of a more substantive response than Ric Gillespie had given it.

A TIGHAR forum member alerted Ric Gillespie to Tom’s online report, and possibly for this reason Gillespie posted a video of his examination of the NEAM C-47 wing back in 2017 on TIGHAR’s YouTube channel [1]. Tom participated in this examination, and the photo below shows Tom and Ric standing alongside the subject C-47 wing at the start of their joint examination.

The photo below shows 2-2-V-1 laid over the C-47 wing at the location of interest. The spacing between five rivet hole lines on the side of 2-2-V-1 closest to the camera matches the rivet line spacing of the underlying C-47 wing quite well. There isn’t a good view in the video showing how closely the rivet hole lines match at other side of 2-2-V-1, but I think it is pretty clear that the alignment is close on that side as well, because nowhere in the video does Ric or Tom say that 2-2-V-1’s rivet line spacings don’t match those of the C-47 wing. So in terms of spacing of rivet hole lines, 2-2-V-1 seems to match up well with Tom’s candidate C-47 wing.

So in what ways might 2-2-V-1 not match a C-47 wing, if not rivet line spacing? Ric offers three primary objections to Tom’s proposed match, which if I understand them correctly are as follows:

  • One line of rivets on the C-47 wing are the wrong sized rivets, i.e., -4 rivets rather than -3 rivets
  • The line of -5 rivets of the C-47 lacks the irregular spacing between 2-2-V-1’s row of -5 rivet holes (these are the rivet holes along the right edge of 2-2-V-1 in the above photo
  • A straight portion of what is the far edge of 2-2-V-1 in the above photo is thought to represent a fatigue failure caused by repetitive bending against a straight object. Ric argues this straight object must an underlying structural component, but no such structural component exists where Ric argues it would need to be.
In the TIGHAR YouTube video, Tom appears to accept Ric’s three objections. However in the days after Ric’s visit, Tom examined the C-47 wing more closely and found reasons to think that he had been too hasty in accepting Ric’s objections:
  • Tom found that the line of rivets Ric thought to be -4 rivets (too big) were actually -3 rivets (matching 2-2-V-1)
  • Tom found that there were irregularities in spacing between -5 rivets, just as on 2-2-V-1
  • In Tom’s opinion, Ric’s hypothesis for the formation 2-2-V-1 straight-edge failure feature was not the only way the straight edge could have been created. Tom suggested instead that “2-2-V-1 was originally larger when removed from the source aircraft. A piece could then have been removed later by placing the artifact between two straight angles and flexed to failure”
All of these points were made by Tom in an email Tom sent Ric Gillespie a few days after the NEAM visit in 2017. That email differs only in small ways from Tom’s online report. My understanding is that Ric Gillespie has never responded to Tom’s email.

All this makes it very hard for me to understand how Ric Gillespie could have recently said that the C-47 wing he and Tom examined is not even close to a match for 2-2-V-1. I can only conclude from the information available to me that Tom Palshaw has found a plausible candidate source for 2-2-V-1, and not only because of the many ways in which the features match, but also because the people of Gardner Island used scavenged aluminum from the Sydney Island C-47 wreck for making handicrafts [2].

I suspect this  post will be followed by several more update posts.

Comments, corrections, additional relevant facts, differing viewpoints, etc., are always welcome.  Send to


[2] Earhart Research Bulletin #7, 7/26/98. Accessible at:

Sunday, November 24, 2019

Is 2-2-V-1 a Piece of the Sydney Island C-47 Wreck?

Since 1992 TIGHAR has argued that piece of aluminum sheet it refers to as artifact 2-2-V-1 found during a TIGHAR expedition to Nikumaroro is a piece of Amelia Earhart's Lockheed Model 10 Electra [1]. TIGHAR's initial case for 2-2-V-1 was that it was a piece of the underbelly of the Electra was quickly debunked. But Ric Gillepsie, TIGHAR's leader, is nothing if not persistent, and so TIGHAR continued over the years to try to find a way to fit 2-2-V-1 onto Earhart's Electra. Many of the key points Gillespie has put forward over the years for 2-2-V-1 being a piece of the Electra have turned out to indicate the opposite but Gillespie simply continues to march forward, steadfastly ignoring or downplaying evidence that goes against his preferred conclusion.

The long history of TIGHAR's claims about 2-2-V-1 is something that I've been wanting to  post about because I think it illustrates problems that arise all too often with TIGHAR's promotion of the Nikumaroro Hypothesis (Gillespie would of course say that he is testing the Nikumaroro Hypothesis, not promoting it, but come on...).  Anyone who scrolls back through my blog posts can see that I'm not exactly a prolific generator of new material. So while my epic blog post series on 2-2-V-1 awaits fruition I'd like to point readers to a report by Tom Palshaw, who works on aircraft restoration projects at the New England Air Museum in Connecticut.  It is pretty clear that 2-2-V-1 isn't from Earhart's Electra, but then what airplane is it from? Tom has suggested a possible answer: he has found that rivet line spacings, rivet types, and aluminum ‘skin’ thickness of artifact 2-2-V-1 match a section of the upper  wing of a C-47 in NEAM's collection.  C-47s were workhorse U.S. military transport planes during World War Two, and significantly, a C-47 crashed on Sydney Island, another island in the Phoenix Island group, during the war [2].  According to TIGHAR, pieces of that  C-47 were brought to Nikumaroro for use by local inhabitants in making items such as combs.

I helped Tom create an online a report of his findings, which can be found here.

I'm certainly no expert on aircraft manufacture but it seems to me that Tom Palshaw has made a good case that 2-2-V-1 is a piece of aluminum recovered from the Sydney Island crash. It also seems to me that the substance of Tom's findings should be better known by TIGHAR's followers than they probably are. Tom informed Ric Gillespie of this putative match back in 2017, but for two years TIGHAR said nothing about Tom's findings on the TIGHAR discussion forum or its Facebook page.  That silence was only broken this summer when Gillespie made the following tersely worded post on TIGHAR forum [3]:

"On July 16, 2017 I inspected the portion of the DC-3/C-47 wing section at the New England Air Museum alleged to resemble Artifact 2-2-V-1. At the time the wing section was out behind the museum, stored outdoors with various other bits and piece of aircraft. There was no way to check the thickness of the skin but, although there were some general similarities in rivet pattern, the rivet type, rivet pitch, and spacing between rivet lines did not match the artifact. Not even close. TIGHAR videographer Mark Smith recorded the investigation."

Gillespie doesn't provide TIGHAR forum members with Tom Palshaw's side of the story although by this time Gillespie had long since received by email from Tom an analysis that is not much different from the online report I've linked to above. Gillespie could simply have quoted from Tom's email or provided a summary of Tom's key points in his post.  Tom sent Ric a photo showing how a template of 2-2-V-1 matches up with the NEAM C-47 wing (see below), and the match looks pretty good to me, certainly close enough to wonder why Gillespie could have made his 'not even close' comment.

Given all the ink that has been spilled about 2-2-V-1 by Ric Gillespie, it strikes me that Tom Palshaw's findings deserve a serious reply from Gillespie. It could be that Gillespie is correct that C-47 wing is 'not even close', but it isn't enough for Gillespie to simply say it, he needs to explain why that is so. 

[1] See TIGHAR TRACKS, Vol. 8 No. 1/2, article titled 'WE DID IT'. Accessible at:
[2] See TIGHAR Earhart Research Bulletin #7, 7/26/98. Accessible at:
[3] See TIGHAR forum thread titled 'RE: 2-2-V-1 Wing Panel Comparisons', post #2. Accessible at:,2074.msg43099.html#msg43099

Note: I originally learned about Tom Palshaw's findings from a post made on the Aviation Mysteries forum. I would link to that post here if I could find it. The post was made long ago and is now buried somewhere deep within the discussion threads there.

Friday, October 26, 2018

The Origin of the Nikumaroro Sextant Box

When I started this blog I knew that I’d be writing about the origin of the Nikumaroro sextant box, but I didn’t think it would take me so long to get to it.  A brief review of what the Nikumaroro sextant box is and how it fits into the matter of the disappearance of Amelia Earhart’s is in order before I get to the main point of this post.

Amelia and her navigator, Fred Noonan, disappeared while attempting to fly across the Pacific Ocean in a Model 10E Lockheed Electra.  They took off from Lae, New Guinea on the morning of July 2, 1937, heading for tiny Howland Island, some 2500 miles away, and were never seen again. The group TIGHAR promotes the Nikumaroro Hypothesis — that having failed to find Howland, Earhart and Noonan landed the Electra on Gardner Island, now known as Nikumaroro, a then-uninhabited atoll located 400 miles to the southeast of Howland.  The Nikumaroro Hypothesis further supposes that a few days after Amelia landed the Electra on Nikumaroro’s fringing coral reef the plane was washed into the ocean and that Amelia and Fred died on Nikumaroro in the following weeks or months.

In support of the Nikumaroro Hypothesis, TIGHAR points to the story of the discovery of the remains of a castaway on Nikumaroro in 1940, not long after the island was settled by colonists from the British Gilbert and Ellice Islands Colony.  The settlement of Nikumaroro was carried out under the supervision of Gerald Gallagher, a British colonial official, in what was one of the final acts of expansion of the British Empire.  In September, 1940, Gerald Gallagher informed his superiors that the partial skeleton of a castaway had been found earlier in the year by a colonist work party, presumably while they were clearing vegetation for the planting of coconut palm trees.

Gallagher reported that searches of the vicinity of the castaway’s remains turned up several items, including a fragment of what he took to be a woman’s shoe and an empty sextant box marked with two four-digit serial numbers — 3500 and 1542.  Gallagher suggested to his superiors that the castaway might have been Amelia Earhart.  Gallagher’s superiors took this suggestion seriously and had the bones and items found near them sent to them for further analysis.  A doctor named David W. Hoodless, who taught at the Central Medical School in Fiji, examined the bones and concluded that the castaway had been a short, stocky male.  The sextant box was examined by Harold Gatty, a world-famous pioneer of air navigation who happened to be in Fiji. It is clear from Gatty’s remarks that he understood that he was being asked whether the sextant box could have come from Earhart’s Electra.  Gatty’s opinion was that the sextant box could not have been that of a navigation sextant used in modern aviation — ‘modern’ here meaning the late 1930s.  With the possibility of the castaway being Amelia Earhart ruled out, there was no further interest in determining the identity of the castaway.

In 1998 TIGHAR had Dr. Richard Jantz, a forensic anthropologist at the University of Tennessee, reanalyze the bones measurements made by Doctor Hoodless during his 1940 examination of the castaway’s bones (the castaway’s bones and the other items found nearby have long since disappeared).  Jantz cautiously concluded that the bones were ‘more likely female than male’ and were ‘more likely white than Polynesian or Pacific Islander’ [1].  This wasn’t exactly a resounding affirmation of the Nikumaroro Hypothesis, but TIGHAR made much of Jantz’s findings, sometimes neglecting to indicate the degree of uncertainty in Jantz’s conclusion.  In 2015 Pamela Cross of the University of Bradford and Richard Wright of the University of Sydney published a paper disputing Jantz’s conclusions, arguing that there was no reason to disbelieve Dr. Hoodless’s original conclusion that the castaway was a man [2].  In response to the Wright and Cross paper, Jantz conducted a new re-analysis of Dr. Hoodless’s notes, and this year published a paper that essentially concluding that there is a high probability that the castaway was Amelia Earhart [3].  I’m not a forensic anthropologist and the subject of this post is the Nikumaroro sextant box, so I will leave the question of whether the castaway was a short, stocky man or Amelia Earhart to those who by training are better qualified to address it.

So now onto the matter of the Nikumaroro sextant box.  The British colonial officials to whom Gallagher sent the sextant box understood that the four-digit numbers it was marked with might allow them to determine the box’s origin, but since they had determined that the castaway wasn’t Earhart this line of investigation was never pursued [4].  TIGHAR took up the challenge of using the serial numbers to trace the sextant box numbers to its owner.  It was eventually learned that the sextants used by the United States Navy in the early decades of the twentieth century are marked with two serial numbers.  One serial number is the sextants manufacturer, and the other is a serial number assigned by the U.S. Naval Observatory, which had the task of inspecting and maintaining the U.S. Navy’s sextants.

Brandis Sextant, Brandis Serial Number 3985

Same Sextant -- its Naval Observatory Serial Number

The boxes made to hold these sextants are marked with the manufacturer’s serial number of the sextant they originally held; some are also marked with the sextant’s Naval Observatory serial number.  The pair of numbers on the Nikumaroro sextant box, 3500 and 1542, match up well with serial number pairings on surviving examples of U.S. Navy sextants made by one particular sextant manufacturer, Brandis and Sons. If 3500 was a Brandis serial number and 1542 a Naval Observatory serial number, there was good reason to think that the Nikumaroro sextant box once held a Brandis sextant made for the U.S. Navy.  As discussed in my earlier posts on the Brandis serial number chronology, a Brandis sextant with serial number 3500 would have been made around the time of the First World War.

How could a World War One era Brandis nautical sextant box be connected to Amelia Earhart’s final flight?  TIGHAR proposed that the Nikumaroro sextant box once belonged to Fred Noonan, Amelia Earhart’s navigator.  Noonan had been a navigator on the Pan Am Clipper seaplanes that were the first to provide passenger air service across the Pacific Ocean. On those flights Noonan used a bubble octant, a kind of sextant made specifically for air navigation, to stay on course for the tiny islands that Pan Am Clippers would stop at to refuel when crossing the Pacific Ocean.  It is reasonable to think Noonan used a bubble octant to navigate Earhart’s Electra [5]. Bubble octants were quite unlike the nautical sextants that Brandis made during the First World War and so were the boxes used to store them.  When Harold Gatty remarked that the Nikumaroro sextant box could not have been used for modern air navigation, what he presumably meant was that the Nikumaroro sextant box was not made to hold a 1930s air navigation octant.

While Gatty’s remarks seem to rule out the possibility that the Nikumaroro sextant box was Noonan’s, TIGHAR points out that in a letter describing his navigational techniques while working for Pan Am, Noonan wrote: “Two sextants were carried – a Pioneer bubble octant and a mariner’s sextant. The former was used for all sights; the latter carried as a ‘preventer’ ”.  It is not clear what Noonan meant by ‘preventer’.  TIGHAR speculates that Noonan meant that he used a mariner’s sextant as a back-up for the Pioneer bubble octant that was his primary navigating instrument.  TIGHAR further suggests that Noonan’s mariner’s sextant was made by Brandis, offering as evidence a photograph of the navigator’s station of a 1930s Pan Am Clipper in which a box that looks like a Brandis nautical sextant box can be seen.  Since traditional nautical sextants were poorly suited for air navigation, TIGHAR further speculates that Noonan’s Brandis sextant had been modified into a Byrd sextant, an early version of an air navigation sextant; a sextant so modified would still fit in its original box.  TIGHAR further speculates that Noonan had his Brandis-Byrd sextant with him on the lost flight to Howland Island,  and that it is the box for this sextant that Harold Gatty passed judgement on in Fiji in 1940.

The case TIGHAR made for the Nikumaroro sextant box being Fred Noonan’s is a circumstantial one, but it nevertheless was plausible.  The big problem with it is that TIGHAR has never been able to prove that Fred Noonan actually owned a Brandis sextant, much less that he had one with him when he and Amelia Earhart disappeared on their way to Howland Island.

I began to follow TIGHAR in 2012, and the hypothesis that the Nikumaroro sextant box belonged to Fred Noonan was of particular interest to me.  At some a point an alternate hypothesis for the origin of Nikumaroro sextant box occurred to me.  In late 1939, only a few months before the castaway’s remains were found, the USS Bushnell, a U.S. Navy submarine tender outfitted as a hydrographic mapping vessel, visited Nikumaroro to survey the island and its lagoon.  My alternate hypothesis was that a Bushnell surveyor inadvertently left the box for the Brandis sextant somewhere in the vicinity of the castaway’s remains, where it was found a few months later in the search for the castaway’s personal effects.  Much of Nikumaroro is covered in forest and scrub and so it is conceivable that a Bushnell surveyor could have passed close to the castaway’s remains without seeing them.

Documents available on the TIGHAR website show that the Bushnell’s surveyors had set up a network of reference points throughout the island for the surveying work they were doing [6].  Some of that work involved measuring water depths from small boats making transects across the lagoon.  It occurred to me that the Bushnell surveyors might have determined their position when making these transects by using sextants to triangulate on the land-based reference points they had set up.  A hydrographic surveying manual published by the U.S. Coast and Geodetic Survey in 1931 confirmed that sextants were in fact used in this way [7].

So, sextants could have been used by the Bushnell surveyors on Nikumaroro, the boxes for those sextants could well have been marked with Brandis and Naval Observatory serial numbers, and a Brandis sextant box left on Nikumaroro by the Bushnell in late 1939 would have been there in time to be found after the discovery of the castaway in 1940.  When I offered up my alternate hypothesis on TIGHAR’s discussion forum, Ric Gillespie, TIGHAR's Executive Director, responded dismissively and with downright hostility, something he often did when a tenet of the Nikumaroro Hypothesis was in some way threatened. To give a sense of how that went I’ll mention that at one point, after I suggested that TIGHAR should search for records that might indicate whether a sextant with serial numbers 3500 or 1542 was issued to the Bushnell, Gillespie’s response was to say any such effort would be ‘wasting time on snipe hunts’; he also said that my hypothesis was ‘thoroughly bizarre’ and that I should ‘go do some real research’ [8]. In the rest of this post, I’ll discuss what Ric might have learned had he spent a few afternoons researching the USS Bushnell at the National Archives in Washington, D.C., a two-hour trip from his home.

My first National Archives trip was in December of 2016. If the Bushnell’s surveyors had used sextants to determine position while surveying Nikumaroro’s lagoon, I had reason to think that they would have recorded the serial numbers of the sextants they used.  The 1931 U.S. Coast and Geodetic Survey’s Hydrographic Survey Manual showed an example of a data sheet for a hydrographic survey on which serial numbers of the sextants that were used are recorded (see photo below).  My goal was to find if something like those data sheets existed for the Bushnell survey of Nikumaroro.

U.S. Coast & Geodetic Hydrographic Survey Data Sheet

My first day was spent at the National Archives and Record Administration (NARA) facility in Suitland, Maryland.  I knew that Suitland was a repository for maps produced by the U.S. Navy and so it seemed like a good place to look for the Bushnell’s field surveying  records if they still existed. At Suitland I was able to find rough maps of the water depths of Nikumaroro’s lagoon that were produced while the Bushnell was still at Nikumaroro.  The raw data from which these maps were prepared were not at Suitland, however.  On the shelves of the Suitland reference room I found a decades-old finding aid for the records of the Bushnell’s hydrographic surveying work.  The finding aid showed that the maps I found at Suitland and notebooks containing the data from which those maps were prepared were at one time kept together somewhere in a single collection. That collection had long since been broken up and the maps eventually ended up at Suitland.  I was told that if the field notebooks for Nikumaroro still existed, they would be at the NARA archive in downtown Washington, D.C.  The Suitland staff member I spoke with held out little hope that those notebooks would still exist.

At the National Archives in Washington the next day I had the good fortune of meeting Chris Killillay, a NARA staff member who has a deep knowledge of the U.S. Navy material held in the archives.  I didn’t have file reference numbers that would help him figure out if the field notebooks I was looking for still existed, or where in the voluminous collection of U.S. Navy material held by NARA those notebooks might be.  Mr. Killillay nevertheless had some ideas about where to look, and after disappearing into the file storage area for a while he came back out and told me that he had found the Bushnell’s field notebooks for Nikumaroro.  I was gobsmacked. I filled out a request form to have the notebooks delivered to the NARA reading room and a little while later up in the reading room a cart came out to me loaded with box after box of Bushnell surveying notebooks, and not only for Nikumaroro but for many other islands that the Bushnell surveyed during its 1939-1940 surveying season.

It was amazing to have the Bushnell’s surveying notebooks sitting in front of me on a cart.  I was probably the first person to ask for them in 70 years.  I located the notebooks for Gardner Island and started to look through them.  Inside there were pairs of preprinted pages on which the measurements needed for map construction were recorded. The photo below shows part of a typical two-page spread.  On the left page are water depth measurements and the times at which the measurements were made, and on the right page are measurements of two angles, indicated as ‘left’ and ‘right’, made on three reference points, indicated as GAR, GUN, and WIT.  The left angle was presumably that between reference points GAR and GUN, and the right angle that between GUN and WIT.  At the end of a series of measurements on some notebook pages the words ‘sextants check’ were written, as can be seen in the second photo below.

Notebook Pages from the Hydrographic Survey of the Nikumaro (a.k.a. Gardner Island) Lagoon

'Sextants Check' on a Notebook Page

 Clearly, sextants had been used in surveying Nikumaroro. But much to my disappointment I was unable to find sextant serial numbers in any of the notebooks I looked through, either for Nikumaroro or for any other island that the Bushnell visited during that same surveying season. I didn’t have time to look through every page of every notebook but I had looked through enough of them to think it unlikely that sextant serial numbers were recorded in any of the notebooks.  Apparently it was considered unnecessary to indicate the specific instruments used to make the measurements recorded in these notebooks. Rather than continue to look through the Bushnell’s notebooks for the 1939-1940 surveying season, I used the remaining time I had at the Archives to look at notebooks for the 1938-1939 season, during which the Bushnell conducted hydrographic surveys along the Caribbean coast of South America.  I managed to find a notebook page that contained the entry ‘Sextant #2806 & #2810 checked’ (see photo below). Here were sextants with four-digit numbers, but the numbers weren’t 3500 or 1542, and it wasn’t clear whether 2806 and 2810 were Naval Observatory numbers or manufacturer’s serial numbers.  I looked through other notebooks like the one in which the 2806 and 2810 appeared, but all of them were devoid of sextant serial numbers.

Sextant Numbers on a Page from the Bushnell Survey of the Coast of Venezuela

That was pretty much as far as I got on my first NARA visit.  The upshot was that I found documentary evidence that Bushnell surveyors used sextants in their hydrographic survey of Nikumaroro, but there was no proof that those sextants were Brandis sextants, much less that one of them was Brandis #3500, USNO #1542.

My next NARA trip occurred in August of this year.  A few months earlier a person named Lew Toulmin wrote a report about the findings of his research into the origins of the Nikumaroro Sextant box [9], which included research at the National Archives in Washington, D.C.  Toulmin examined an index card catalog for NARA’s holdings of U.S. Naval Observatory’s correspondence for the period 1909-1925.  The card catalog was organized by subject, and one of those subjects was sextants.  Each card gave a terse summary of correspondence in a Naval Observatory file and a file number that could be used to locate the actual correspondence.  Toulmin found nothing on the cards he looked through that allowed him to determine the origin of the Nikumaroro sextant box. On this Archives trip I wanted to have a look at the 1909-1925 card catalog that Toumlin had already looked through, because I thought it would point me to Naval Observatory correspondence that would allow me to refine the Brandis serial number chronology that I’ve discussed in earlier posts.  But I was also interested in a second card catalog that Toulmin hadn’t looked at, which was for NARA’s holdings of U.S. Naval Observatory correspondence for the period 1925-1943.  My thought was that the Naval Observatory, in its role as the U.S. Navy’s sextant service shop, might have supplied the Bushnell with Brandis sextants, and the 1925-1943 card catalog might point me to documents attesting to this. 

As I started to go through the index card catalogs in NARA’s reading room I quickly realized what a daunting task it was to glean information from them. There were a huge number of index cards on the subject of sextants and many of the cards were handwritten in a nearly illegible script. It was impossible to digest the information on the 1909-1925 index cards while sitting in the NARA reading room, so all I could do was photograph them so that I could decipher them when I got home. The 1925-1943 card catalog was easier to read, but I only found two index cards under the subject of sextants that seemed to have potentially promising leads. The first card read:

Sextants, patrol Bt. Brandeis - unfit for use - 144 turned in to N. Obvy - Supt. N. Acad. 1/14/37 - 2-2X3.

Brandeis’ was obviously a misspelling of Brandis, and I recognized ‘Sextants, patrol Bt.’ to be a reference to the 5-inch radius Brandis sextant that I wrote about in the post titled ‘Brandis Sextant Taxonomy, Part Five’. All the Brandis sextants of this type that I knew of had Brandis serial numbers in the 3000s, not far off from the presumed Brandis serial number on the Nikumaroro sextant box. Perhaps the full Naval Academy memo this card summarized actually listed the serial numbers of the Brandis patrol boat sextants that were turned into the Naval Observatory.  In Brandis Sextant Taxonomy, Part Five I noted that sextants of this type had features that made them well-suited for hydrographic surveying.  So when I saw this index card I wondered if the sextants were refurbished at the Naval Observatory and sent to the USS Bushnell. The Naval Academy letter was dated January 14, 1937, so there would have been enough time to get those sextants fixed and to the Bushnell in time for the voyage on which the Bushnell surveyed Nikumaroro.

The second index card read:

U.S.S. Bushnell - 1004 - Rq. for sextant mirrors - 24 Index + 24 Horizontal - C.O. 8/4/38. 2200.
6105  Yr. 1004 2200 Shipped this date P.P. Navobsy. Inv. 290 — To C.O. 8/5/38   1500

There was no mention of sextants in the terse summary written on this index card, but I wondered if the full message that the card summarized might say something about sextants.  By the time I found these two cards it was too late in the day to have the files for this correspondence retrieved.  My visit to the Archives had come to an end, and so I would have to come back another time to follow up on the two index cards.

It wasn’t until last week that I was able to return to the Archives and access the files that the cards referred to. I was disappointed to find that the full Naval Academy letter summarized on the first card said nothing about the serial numbers of the Brandis patrol boat sextants sent to the Naval Observatory.  The correspondence on the second card also led nowhere; what was written on the card was basically the full extent of the correspondence, which apparently had occurred by telegram or radio.

The information on those two index cards led me nowhere; I had reached a dead end. Was there anywhere else in the Archives left to search? The two disappointing index cards were filed under the subject ‘Sextants’ in the card catalog, and I remembered that further along in the card catalog were cards filed under the subject ‘Surveying Instruments’.  I went back through those index cards and found a few cards summarizing correspondence between the USS Bushnell and the Naval Observatory.  The card in the photo below was particularly tantalizing.  It summarized a chain of correspondence between the Bushnell and the Naval Observatory about surveying instruments that the Bushnell had sent to the Naval Observatory for repair in late 1938.  I put in a request for the files for this correspondence, but the file boxes that came to up to me in the NARA reading room didn’t contain the corrspondence I was looking for.  Chris Killillay was on duty when I went downstairs to the room where NARA archives specialists meet with researchers, and I told him that I had been unable to find the correspondence I wanted.  He went into the file storage area for a while, and when he came out he helped me fill out a request form for a file box that he thought was the only one left in the Archives that might hold the correspondence I wanted.

Index Card from the USNO Correspondence 1925-1943 Card Catalog

When that file box came to me in the NARA reading room I quickly saw that it contained the correspondence I wanted to see.  I found a memo to the Naval Observatory written by the commanding officer of the Bushnell in October of 1938 stating that the Bushnell would be sending surveying instruments to the Naval Observatory for repair; nineteen sextants were among the instruments to be sent. The Bushnell's C.O. was giving the Naval Observatory advanced notice because he wanted to make sure he got those instrument back in time for his next hydrographic survey cruise.  No serial numbers or manufacturer’s names were given for the sextants or for any of the other listed instruments.

A little further into the chain of correspondence I came upon a four page memo from the Bushnell dated November 15, 1938, listing each instrument to be sent to the Naval Observatory and the specific work that needed to be done.  The first two pages of this memo are reproduced below.  Item 12 on the list is 'Sextant, Brandis N.O. 1542  General Overhaul'.  A note penciled into the margin indicates that this sextant was returned to the Bushnell on January 17, 1939.  The ’N.O.’ is obviously an abbreviation for Naval Observatory [10].  So here in this memo it is documented that a Brandis sextant with U.S. Naval Observatory number 1542 belonging to the USS Bushnell was refurbished by Naval Observatory in late 1938 and was back aboard the Bushnell by January of 1939, about a year and a half after Amelia Earhart and Fred Noonan went missing, and about a year before the Bushnell stopped at Nikumaroro to survey it.  The sextant box found on Nikumaroro marked with the numbers 3500 and 1542 wasn’t Fred Noonan’s, it was a Brandis sextant box that a Bushnell surveyor happened to lose in the vicinity of the remains of the castaway’s final campsite.

List of Items Shipped from the Bushnell to the Naval Observatory, Page 1

List of Items Shipped from the Bushnell to the Naval Observatory, Page 2

Marginal Note on Page 2 Indicates Items 11 through 15 Returned to the Bushnell on 1-17-39

Comments, corrections, additional relevant facts, differing viewpoints, etc., are always welcome.  Send to

[1] Amelia Earhart’s  Bones and Shoes? Current Anthropological Perspectives on an Historical Mystery.  This report was ‘prepared for release’ at the 1998 annual convention of the American Anthropological Association. It can be downloaded at the TIGHAR website:

[2] The Nikumaroro Bones Identification Controversy: First-hand examination versus evaluation by proxy - Amelia Earhart found or still missing? Pamela J. Cross and Richard Wright. Journal of Archeological Science: Reports 3 (2015) 52-59.

[3] Amelia Earhart and the Nikumaroro Bones: A 1941 Analysis versus Modern Quantitative Techniques. Richard L. Jantz.  Forensic Anthropology Vol. 1, No. 2: 83–98

[4] Actually, at this point the colonial officials thought that a sextant with the numbers 3500 and 1542 had been found, not just an empty sextant box, but the idea is the same.

[5] Noonan borrowed a Pioneer aviation bubble octant from the U.S. Navy.  The signed receipt indicates it was to be used on the round the world flight with Amelia Earhart.  A copy of that receipt can be found at:

[6] Tighar’s collection of Bushnell documents is available for download at:

[7] Hydrographic Manual, U.S. Coast and Geodetic Survey Special Publication No. 143.  J.H. Hawley. U.S. Government Printing Office, Washington, D.C. (1931)

[8]  My quotes come from Replies 40, 41 and 121 on the Seven Site Thread  of the TIGHAR discussion forum (,508.0.html). There were other insulting remarks and a strange degree of obtuseness about my hypothesis from Gillespie and some of his loyal followers. 

[9] Toulmin’s report is titled: SEXTANTS AND NOONAN/EARHART: The Pensacola Fred Noonan Sextant and Box and the Amelia Earhart—Fred Noonan Disappearance and Sextant Research on the US Naval Observatory at the US National Archives.  It is dated May, 2018.  Mr. Toulmin’s report will be published on his website,, on the page on Finding Lost Airplanes.  Until then it is available  upon request at 

[10] We can be sure that 1542 was the sextant’s Naval Observatory number, not its Brandis serial number by looking at item 8, a Keuffel and Esser protractor, for which both the manufacturer’s number, K&E #10013, and Naval Observatory number N.O. #176, are given.