Forum artHighlights From the Forum

June 3 through 9, 2001

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Radios: Woulda Coulda Shoulda Patrick Gaston
Re: Radios: Woulda Coulda Shoulda Alan Caldwell
Re: Radios: Woulda Coulda Shoulda Ross Devitt
Niku Reef Edge Christian D.
Niku Reef Edge John Watson

Message: 1
Subject: Woulda Coulda Shoulda
Date: 6/5/01
From: Patrick Gaston

Serves me right for lapsing into colloquialisms on a Forum filled with technical types! Yes, Ric, I'm aware of the both the Army report on the Luke Field crash and Sgt. Rose's report on the Darwin difficulties, both of which ascribe the problem to a blown generator fuse and not the generator or transmitter itself.

I also should have said that the details of the Darwin malfunction were "confusing" rather than sketchy. Confusing because AE said the problem was in her "D/F receiver" while Rose found that it was a fuse in the "D/F generator," both comments suggesting that Earhart had a separate generator for the D/F equipment -- something which we don't know for a fact; which, I believe, TIGHAR denies; and which I therefore wanted to stay away from. We also don't know the circumstances under which the failure occurred. Darwin complained they "heard nothing" from her, but did they mean voice or a D/F signal? Why would a problem with the "D/F generator" affect voice communications? Etc., etc.

So I will accept 20 lashes with an antenna wire for my sloppy use of the vernacular. Manning didn't "blow the transmitter." He (apparently) pressed the key that blew the fuse that protected the generator that supplied the current that recharged the batteries that powered the electrical system (that included the radio, that was composed of a transmitter and a receiver) that was housed in the plane that Lockheed built. Something similar, which is not to say identical, happened on the approach to Darwin.

But the fact remains that Earhart's electrical system was demonstrably susceptible to failure -- perhaps from all that new-fangled equipment on board -- and keying the transmitter for more than a few seconds at a time seems to have provided the straw that broke the camel's back (metaphorically speaking; we are reasonably certain that no camels, bactrian or dromedary, were aboard the Electra). As Mike E. points out, even keying the transmitter for a full minute should not have been enough to produce this result under ordinary circumstances, "unless the rig is severely mistuned." Or, one might add, unless the electrical system already was loaded to the gills.

One could also theorize that this known susceptibility explains why Earhart's transmissions on the Lae/Howland run were both infrequent and brief. She was aware of the problem, and the last thing she wanted was a dead radio when she needed it the most, i.e., on the approach to Howland.

You speculate that, even with a blown generator fuse, AE shoulda been able to transmit for a short while on battery power alone. You point out that this phenomenon is not reflected in the Itasca radio logs, implying that no such malfunction occurred. But it could also mean that your premise is wrong. Certainly there is no mention in Last Flight of any further transmissions after the generator (fuse) went south. I would like to hear Mike E's take on this question. How long could AE have transmitted on batteries alone? Was her other instrumentation drawing power from these same batteries, and how would that affect the equation? What if the "rig" had indeed been mistuned, either by Gurr or by Balfour's subsequent fiddling at Lae? Would this have compounded the problem?

Lost in all of this is the whole point of my original post -- which was was to challenge the assertion that the seeming lack of urgency in AE's final transmission necessarily meant she had lots of fuel left.

Pat Gaston

Message: 2
Subject: Re: Woulda, Coulda, Shoulda
Date: 6/5/01
From: Alan Caldwell

Pat Gaston wrote:

> Lost in all of this is the whole point of my original post -- which was was
> to challenge the assertion that the seeming lack of urgency in AE's final
> transmission necessarily meant she had lots of fuel left.

Pat, I agree. The two don't necessarily go together. In flying school I was shooting a forced landing in a T-28. My instructor in the back seat keyed the intercom and in a quiet casual voice said, "Caldwell the reason you would have a forced landing is that you have lost your engine and you wouldn't have it to get you out of trouble. At the moment your airspeed is about 2 knots above stall so what you want to do is......"

He was calm as I was about to fall out of the sky. I was the one who expressed great urgency.


Message: 3
Subject: Re: Would Coulda Shoulda
Date: 6/6/01
From: Ross Devitt

Pat Gaston wrote:

>What if the "rig"
> had indeed been mistuned, either by Gurr or by Balfour's subsequent fiddling
> at Lae? Would this have compounded the problem?
> Lost in all of this is the whole point of my original post -- which was was
> to challenge the assertion that the seeming lack of urgency in AE's final
> transmission necessarily meant she had lots of fuel left.

Don't forget, there is at least one documented occasion of Earhart transmitting, then changing frequencies against advice and losing contact. Oddly, if I recall correctly, the frequency change was the other way around. The situation was vaguely similar. She was being read quite clearly on once frequency, announced she intended to change frequencies and was requested not to.

She changed anyway, and contact was lost until the approach to Howland when she was heard on the frequency that she had switched to when contact was lost.

Careful reading and re-reading of the report suggests that she was in two way communication that night, but does not actually say it, therefore we have usually assumed -- with good reason -- that she was only being heard.

The following quote indicates that on the day before they departed Lae the Electra had 2 way communications:

"At 6.35 a.m., July 1st, Miss Earhart carried out a 30 minute air test of the machine when two way telephone communication was established between the ground station at Lae and the plane."

And this one suggests that for the first part of the flight at least there was 2 way communications on 6210Kcs:

"The Lae Operator heard the following on 6210 KC -"HEIGHT 7000 FEET SPEED 140 KNOTS" and some remark concerning "LAE" then "EVERYTHING OKAY". The plane was called and asked to repeat position but we STILL COULD NOT GET IT." (my capitals)

'Asked To Repeat Position But We Still Could Not Get It' implies that the Earhart replied to their request. No further signal was received once she was on 3105.

In the morning however, she was received on 3105, but could not hear Itasca. It is documented that she considered 6210Kc to be her daytime frequency, and it appears it had been working in 2 way communication the day before so I suppose it was logical to at least try that frequency.

What interests me is why Earhart was heard by Itasca on 3105Kc until well into the morning when she used 6210 during daytime? I would have thought she'd change frequency sooner.


From Ric

You and I have debated this before. There's no way to know whether or not Earhart's repetition of the message that Balfour couldn't understand was in response to his request. It does appear that two-way communication was achived during the test flight and it's abundantly clear that Earhart experienced difficulties in that respect the very next day -- so it's worth asking, what was different?

From a reception standpoint we have the photographic evidence that she lost the belly antenna on takeoff. We don't know for sure what significance that had, but it's certainly something that was different. From a transmission standpoint, the test on July 1st was carried out virtually on top of the station. After departure on July 2nd it was four hours before Lae heard any of the hourly reports Earhart had promised to send. Because she was using 6210 at that time, the implication would seem to be that if the airplane was between one hour and four hours away (call it 100 to 500 miles) it could not be heard on 6210. Sound familiar?


Message: 4
Subject: Niku Reef Edge
Date: 6/6/01
From: Christian D.

I just flew out of Christmas Island: the airstrip is close to the shore, and the plane veers sharply very soon after take off, and indeed I have noticed colors which could indicate lots of roughly parallel canyons...

I could not judge depth differences, but the darker greenish fingers are there, obviously coral growth, may be 100ft long or much more, separated by a fraction of that distance. The space between the fingers looks like light colored sand, and hence quite possibly a "canyon"... From the varying shade of the coral "green", it seemed to me the finger top might not be quite level, but sloping down and out.

Now Xmas is in another island group, but Palmyra (just next door) seemed very similar to Kanton, as far as I could compare them from hiking on the reef flats.

I too could visualize these places as some kind of an "airframe catcher" on the edge of the reef drop off.

If needed, Kim, who runs a Dive shop on Xmas should be able to give more details to these structures.

Which reminds me: wasn't Nai'a supposed to do some reef exploration on their own a while back, to satisfy their own interest?

Christian D.

PS: by the way, the locals spend lots of time on Xmas diving for petfish for export, and I would suspect that they also visit these canyons. Also people go snorkelling in there to catch lobster for local consumption.... May be we should hire a couple of experienced local people? And the site of interest on Niku is on the sheltered side of the island, so it might be rather safe, on settled days.

From Ric

The information we're getting tends to support the idea that the canyons are no problem, as long as the sea is relatively calm. I also suspect that if the sea is rough there is no way to make it safe to go near the darn things. So we wait for a calm day.

Message: 5
Subject: The Reef Edge
Date: 6/7/01
From: Jon Watson

Have to say this – I move that henceforth divers from the Niku expeditions (past and future) HAVE to be known as Tighar Sharks.

By the by, how do these ravines, canyons, fingers, or whatever, end on the seaward side? Do they just keep getting gradually bigger and bigger (that is wider and deeper), or is this where everything just suddenly drops off to the bottomless pit?

jon 2266

From Ric

The 1989 dive team became known as The Bubble Heads. Don't ask.

I dug out the video they shot of the canyons they looked at. Pretty amazing stuff. There's footage of two canyons, both of which were reportedly south of Tatiman (pronounced Tasman) Passage – the main lagoon passage. The day was very calm and the underwater visibility was excellent.

The first canyon began at a water depth I estimate to be about 30 feet and went for perhaps 50 yards before ending in a jumble of coral boulders at a depth of what appears to be about 10 feet. Of course, there's no way to tell from the video what the state of the tide was. The seaward-side mouth of the canyon was about twelve feet across and gradually narrowed to about five feet across at the shallow end. The diver had no difficulty negotiating the canyon but the seaward surge of retreating water sucked him a few feet backward with each wave that passed overhead. On this particular day, the waves were not running parallel with the canyon but at about 45 degrees across its long axis.

The canyon was not a simple straight crack running toward the beach but had some minor changes in direction, a few branches running out to either side, and several large coral outcroppings in the middle along the way. An object of any appreciable size that fell into the canyon at the shoreward end would stand virtually no chance of being swept out and over the steep lip of the reef without getting hung up. You couldn't design a better wreckage-trap if you tried.

The floor of the canyon appeared to be pea-gravel sized chunks of coral rubble of indeterminate depth (but probably not more than a foot or two deep).

The second canyon was narrower and shorter than the first, becoming almost cave-like at one point as the walls closed in overhead. Otherwise it was very much like the first one.

It's clear from the video taken in 1989 that the underwater reef-edge environment off the west end of the atoll is not a simple drop into oblivion but features several yards of gradually descending terrain that is a very rugged jumble of coral. This is "the ledge" we've talked about. Along the shoreward side the ledge is periodically cut with spurs and grooves (canyons). On the seaward side it really does drop into oblivion.

From what I can see, it should be no problem for our divers to check out the reef edge approaching from seaward underwater at high tide on a calm day. Approaching from the landward side, walking on the reef flat, is probably not a good idea even on a calm day at low tide unless the area is already explored and mapped by the divers. In other words, if the divers find something worth investigating and it's in really shallow water, we might be able to get to it from the landward side safely if conditions are right.


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