Perhaps the 1/2 hour fuel comment didn't really happen ...
From "The 1937 Search: The First 24 Hours" by Randall S. Jacobson, Ph.D.:
Thompson’s actions apparently were based upon his conviction that Earhart had said, at 07:42 (1912 GMT), that she only had half an hour of fuel left. Because there is no land other than Howland and its sister island Baker which could possibly be reached within that fuel limitation, the conclusion that the airplane went down at sea is inescapable. If the quote is accurate Thompson was certainly correct in beginning the search rather than sitting at Howland waiting for an airplane that was already in the water. Where does the quotation come from? The only source is what Thompson calls the “Other Log” which he quotes in his July 19th report as saying “Earhart on now says running out of gas only 1/2 hour left.” The entry was made by Radioman 3rd Class O’Hare who had been on watch since 02:00. Evidence that the phrase was not said includes: - Radioman 3rd Class Galten’s entry in the Itasca’s radio log, “KHAQQ calling Itasca. We must be on you but cannot see you but gas is running low. Been unable reach you by radio. We are flying at a 1,000 feet.”11
- An entry in the Itasca’s deck log by Lt. (jg) W. J. Sevarstan, “0742 Planes position reported as near the island and gas running low.”
- Lt. Cooper’s report, “0741. Earhart. We must be on you but cannot see you but gas is running low...”12 However, this is a second-hand report, as Cooper was still on Howland Island.
- The July 4th press release sent by Itasca, “0730 Quote we must be on you but cannot see you but gas is running low...”13
- At 08:43 (2013 GMT), a full hour after Earhart supposedly said she had “only 1/2 hour gas left,” Earhart was still aloft and transmitting.
- Not once in the three messages received by Itasca after the 07:42 message did Earhart repeat her concern over fuel.
- In Thompson’s typed report the quote from the “Other Log” is followed by the parenthetical comment “(unverified as heard by other witnesses)” but the “un” in “unverified” has been lined through by hand.14 However, it is impossible to determine when this line-out occurred and/or whether it was there when originally delivered to the Coast Guard.
- The available evidence argues strongly that the phrase “½ hour gas left” was never said. It may, in fact, have been a simple misunderstanding. In three of the nine transmissions heard by Itasca, including the next message received 16 minutes later, the ship’s radio log recorded Earhart’s use of the phrase “half hour,” but always in reference to the radio schedule, never to fuel.
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It is Friday evening and you are leaving the office. One of your office mates suggests that a few
of you stop for a beer at the sport bar that is on your way home. So you guys stop for a beer and
while ordering a second round, watching a Cubs game on the big screen TV, you strike up a
conversation with a stranger standing at the bar. He introduces himself as “Jim.”. He says he just
recently moved to this town and asks you if there are any good restaurants in the area. You say to
him, “I live down near the corner of First Avenue and Main Street and there are a number of
very good restaurants right at that corner.” Jim says, “wow, that is good to know, I live at Third
and Main so those restaurants will be convenient for me and my wife.”
When you get home you tell your wife that you met a newcomer named “Jim” and “that he lives
at Third and Main.” Later you tell your son about this meeting and tell him, “Jim lives close to
us.”
The next Friday you are again at the same bar and this time you meet “Bill.” Pretty much the
same story as with Jim and you tell Bill the same thing, “I live down near the corner of First
Avenue and Main Street and there are a number of very good restaurants right at that corner.”
Bill says, “that is good to know since I live close to there.”
You go home and tell your wife about this meeting. You tell her, “Bill lives close to us.” But
you cannot say to her the same thing you told her about Jim something like “Bill lives at the
corner of Third and Main” because you do not have that piece of detailed information. If you just
made up a detail like that then you would be lying.
In Jim’s case, both of your two statements tell the truth, you know from his address that he “lives
close to you” so your generalized paraphrasing of his actual words is still telling the truth and is
commonly done, especially when making notes. But when making notes you do not make up a
detailed “fact” when you only have a general statement to work from. Think back on your own
experience, I’ll bet that you have often paraphrased information into a general form but that you
haven’t made up detailed “facts” from just a general statement.
One of the radio logs contains: “Earhart on now, says running out of gas, only ½ hour left, can’t
hear us at all.”
The other log records: “We must be on you but cannot see you, but gas is running low, been
unable to reach you by radio.”
If Earhart had said only “gas is running low” or “running out of gas,” if you were the radio
operator would you have made up the specific and detailed “only ½ hour left” and entered it in
your log? I thought not.
Or is it more likely that she actually said "half hour of fuel left" and the other radio operator
paraphrased that to the more general "running low on fuel?" Writing down a more general
summary from a specific statement is still speaking the truth, a ”half hour left” IS “running out
of gas.” But going the other way means "making up" the "half hour" fact and so is NOT a true
statement if she didn't actually say it
The Niku people and the Mili people and the New Britain people do not like Earhart’s statement
but if your keep an open mind I think you will agree she most likely actually said “only ½ hour left.”
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But she was still flying a full hour after her statement was logged so is this proof that she did not
say “only ½ hour left?”
Well, no.
The fact that the fuel lasted an hour after Earhart reported only one half hour left is unsurprising.
Fuel gauges in airplanes are notoriously inaccurate today and they were no better 74 years ago.
Federal regulations (posted below) requires that the fuel gauge only has to be accurate at one
point, it must read "zero"at the level of "unusable fuel" which is fuel remaining in the tanks that
might not be usable in extreme flight attitudes such as holding the nose extremely high or in
slipping or skidding flight or if doing aerobatics. You
can use this "unusable fuel"
if you fly at normal flight attitudes. Another way to look at this regulation is that the engine can not run out
of fuel prior to the gauge indicating "zero" but the engine may continue to run after that point if you maintain
normal flight attitudes. So if Earhart looked at the fuel gauge and estimated that there was only a
half hour left until it reached "zero" then it is not surprising at all that there was an additional half
hour of "unusable fuel” remaining after the gauge got down to "zero" and that this “unusable
fuel”continued to feed the engines since they were not doing any extreme maneuvering.
Here are the current Federal Aviation Regulations found in title 14 of the Code of Federal
Regulations “CFR.” Part 23 prescribes the requirements for certification of airplanes such as
Earhart’s Electra. Prior to the current Federal Aviation Regulations, aircraft had to meet the
requirements in the Civil Air Regulations, Part 3. CAR 3.437 and CAR 3.672 spelled out the
exact same requirements for fuel gauges.
14 CFR 23.1553:
§ 23.1553 Fuel quantity indicator.
A red radial line must be marked on each indicator at the calibrated zero reading, as specified in
§23.1337(b)(1).
§ 23.1337 Powerplant instruments installation.
......
(b) Fuel quantity indication. There must be a means to indicate to the flightcrew members the
quantity of usable fuel in each tank during flight. An indicator calibrated in appropriate units and
clearly marked to indicate those units must be used. In addition:
(1) Each fuel quantity indicator must be calibrated to read “zero” during level flight when the
quantity of fuel remaining in the tank is equal to the unusable fuel supply determined under
§23.959(a);
§ 23.959 Unusable fuel supply.
(a) The unusable fuel supply for each tank must be established as not less than that quantity at
which the first evidence of malfunctioning occurs under the most adverse fuel feed condition
occurring under each intended operation and flight maneuver involving that tank. Fuel system
component failures need not be considered.
see:
http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=f0270f2e0237f7e8240bd450104e78e0&rgn=div8&view=text&node=14:1.0.1.3.10.6.100.17&idno=14
gl