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Author Topic: 17:47 GMT Transmission  (Read 40492 times)

John Ousterhout

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Re: 17:47 GMT Transmission
« Reply #30 on: February 18, 2012, 08:03:18 AM »

"... improves the glide performance."

Gary,  do you have any estimate of the expected descent rate with both engines out and both props in "low drag" position?
Cheers,
JohnO
 
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Harry Howe, Jr.

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Re: 17:47 GMT Transmission
« Reply #31 on: February 18, 2012, 10:37:41 AM »


John
Been a long time but I think my Piper Warrior PA 28-160 had a fixed prop and a glide ratio approaching 10 to 1  Hardly a brick.
No Worries Mates
LTM   Harry (TIGHAR #3244R)
 
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Gary LaPook

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Re: 17:47 GMT Transmission
« Reply #32 on: February 18, 2012, 02:42:27 PM »

"... improves the glide performance."

Gary,  do you have any estimate of the expected descent rate with both engines out and both props in "low drag" position?

With most twins you don't lose both engines at exactly the same time
because the engines are being fed from two separate tanks and they don't
hit empty at exactly the same time. Earhart's plane was different and
the fuel system did supply both engines from the same tank so AE would
lose both engines at the same time when she ran out of fuel. From repoort 487
I computed that her max L/D ratio was 11.89 which would be approximately her
glide ratio but it would be something less, due to the drag of the windmilling
propellers so a ratio of 10 to 1 is reasonable to assume. At her empty
weight, the best glide speed would be about 100 mph so this means she
would be going down at a rate of 10 mph which is 14.7 feet per second.
One thousand feet divided by 14.7 feet per second means the airplane
would splash down in 68 seconds. Different reasonable assumptions for
glide ratio and best glide speed won't make a big difference in the time
to splash.

Every book that discusses ditching recommend making a controlled
ditching prior to using the last drop of fuel. With power still
available you can choose the best heading that is parallel to the swells
and you can adjust your touch down point to avoid hitting the face of a
wave and can land on top of the swells which gives you the best chance
for survival. According to AFM 64-6, Aircraft Emergency Procedures Over
Water
, with winds less than 25 knots you do not try to land into the
wind but land parallel to the swells. If the swells are not
perpendicular to the wind then choose the heading that is parallel to
the swells and has the larger headwind component. Only with a wind speed
greater than 35 knots should you select a heading directly into the
wind. Between 25 and 35 knots you choose an intermediate heading.

gl
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Monty Fowler

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Re: 17:47 GMT Transmission
« Reply #33 on: February 19, 2012, 11:35:42 AM »

"so AE would lose both engines at the same time when she ran out of fuel."

That's an assumption, Mr. LaPook. You weren't there. Neither was anyone else who participates on these discussion boards (that we are aware of) - so flatly making statements about what the final moments of her flight were like are, at best, idle speculation. And so are any scenarios derived from same, without hard evidence to back them up.

LTM,

Monty Fowler,
TIGHAR No. 2189 CER
Ex-TIGHAR member No. 2189 E C R SP, 1998-2016
 
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John Joseph Barrett

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Re: 17:47 GMT Transmission
« Reply #34 on: February 19, 2012, 12:15:42 PM »

Actually, no disrespect Monty, I think Gary is correct on this. If both engines are drawing from the same tank, they would both lose power at the same time, or very nearly so. The only differences between which goes first would be due to a fairly significant difference in the mixture settings and a greater length of plumbing of the fuel lines. I don't think, given the rate of fuel burn, that the length of lines is going to provide enough extra fuel to keep one engine turning much longer than the other. Essentially, they are both going to lose power close enough to the same time to say it is. As a non-pilot, why would you want both engines drawing from one source? Seems to me if you encounter a fuel problem in a twin, you would at least have some time to sort it out if one engine remains on line. Where all Electras plumbed to draw from one tank for both engines or was that due to the additional tanks in this Electra?   LTM- John
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JNev

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Re: 17:47 GMT Transmission
« Reply #35 on: February 19, 2012, 12:50:18 PM »

John,

Yes, Gary's more or less correct in the narrow technical sense - IF AE got to that point.

However - and with no disrespect to you or Mr. LaPook, what I see in Monty's post that I strongly agree with is that here Gary is slipping flame-out and ditch-n-sink into the '17:47 GMT Transmission' thread - as if a statement of fact.  What, pray tell, would have led to this predicament? 

There was ample fuel remaining at this point according to all we know about NR16020's capacities and endurance capabilities.  How odd that we've been led to 'splash-n-sink' so quickly from a humble review of the rising sun and it's import on the flight's placement...

LTM -
- Jeff Neville

Former Member 3074R
 
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Harry Howe, Jr.

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Re: 17:47 GMT Transmission
« Reply #36 on: February 19, 2012, 01:03:59 PM »


John Joseph
Aircraft designer/builders have learned not to put all there fuell eggs in one basket so to speak and present twins don't draw from one tank.
Also pilots are trained to alternate fuel usage from fuel in one wing tank to the other for reasons of balance. We're also taught to draw from fuel from both tanks during critical times in the flight, like takeoffs, climbs, landings, etc.
You may  rmember the John Denver fatal crash.  The plane he had just bought was a home-built that had the fuel tank selector valve controller in a non-standard location (behind his  left shoulder) and it required a tool (pliers, channel locks) to operate it.
I hope I have the salient facts right, but Gary LaPook can correct me, he was an attorney in the law case.  When the fuel was exhausted in one wing tank and he was, pesumably, trying to switch to the other wing tank the engine stopped turning, as engines are want to do without fuel, and he went into the water.

Unevaluted CHANGE can lead to unexpected and undesirable CONSEQUENCES.
No Worries Mates
LTM   Harry (TIGHAR #3244R)
 
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Gary LaPook

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Re: 17:47 GMT Transmission
« Reply #37 on: February 19, 2012, 01:39:54 PM »

. As a non-pilot, why would you want both engines drawing from one source? Seems to me if you encounter a fuel problem in a twin, you would at least have some time to sort it out if one engine remains on line. Where all Electras plumbed to draw from one tank for both engines or was that due to the additional tanks in this Electra?   LTM- John
Yes, as hard as it is to believe today, the standard fuel system on Electras had both engines fed from the same tank. There were two selector valves in series mounted low on the instrument panel as shown on Amelia's plane. The first one selected one of the four wing tanks and the second valve selected the engines to be fed from that tank. An Earhart's plane they add a fifth position on the tank selector valve that then went to the cabin tanks. Today's regulations would not allow such a fuel system.

gl
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Tom Swearengen

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Re: 17:47 GMT Transmission
« Reply #38 on: February 19, 2012, 05:05:35 PM »

Gary was an attorney in the John Denver case? Is that correct Gary? ----
HUM
Tom Swearengen TIGHAR # 3297
 
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Irvine John Donald

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Re: 17:47 GMT Transmission
« Reply #39 on: February 19, 2012, 06:30:31 PM »

That's right Gary. Rules in 1937 were different than today. It has been mistakes made in history that guide us today. Mechanical and electronic components have improved. New aids developed. Procedures improved.  But people don't change. Just their training. AE and FN would have used their heads when they didn't find Howland. They would have used their training and nav skills to come up with a plan  Or did they really just stick with trying to find Howland with searches until they ran out of fuel. No other plan?
Respectfully Submitted;

Irv
 
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Harry Howe, Jr.

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Re: 17:47 GMT Transmission
« Reply #40 on: February 20, 2012, 10:49:56 AM »


Jeff
Assuming that AE had only a half hour of fuel at 2025 GCT, 0843 Itasca, and Thompson knew she was flying N&S on 157/337, why didn't he put in a launch to search N and go S with the Itasca?    Tunnel Vision, a military failing?
No Worries Mates
LTM   Harry (TIGHAR #3244R)
 
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Irvine John Donald

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Re: 17:47 GMT Transmission
« Reply #41 on: February 20, 2012, 11:55:11 AM »



One good point from all the fuel talk drift here - the Electra did have a fairly simple fuel system.  I don't see evidence in what we know of the system being mishandled and causing an early loss of the flight.  I think that is unlikely to have happened.

LTM -

All very good points Jeff.  Your last point above reminds me that IF there was a mechanical issue with fuel consumption or excessive burn rate then the fuel gauge would have shown there was an issue. AE and FN would likely be matching fuel consumption to distance flown and realize there was an issue.  I would think they would have returned to Lae if this rapid fuel consumption was detected before the point of no return. I speculate that IF there was a fuel consumption problem the it was after the point of no return and AE would have likely made some reference to it.  Why make a reference?  A decent sized ship is waiting for them. No other task but to support AE. IF she had a fuel problem past the point of no return then call for help and ask Itasca to come to your assistance before you possibly run out of fuel.  Easier and safer to ditch beside the cutter instead of on your own with no survival gear including Very pistol.

But why no mention of this?  Because we already know the Electra had enough fuel.

So Harry, if you're down to a half hours fuel wouldn't you be trying to get Itasca, idly sitting at anchor waiting for you, to come to you?  Even though she had poor radio contact she still transmitted as though people could hear her.  If she thought she was going to ditch Gary then why not attempt to get Itasca to come to her.  At least send a message on all radio channels she had saying "ditching now...position is xx yy". 
Respectfully Submitted;

Irv
 
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Harry Howe, Jr.

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Re: 17:47 GMT Transmission
« Reply #42 on: February 20, 2012, 12:23:58 PM »


IRV
My comment about the "launch" was just a comment on Thompson's actions in steaming off to the NW.
I personally don't believe the "pnly half hour fuel "  entry.  I believe she had 5, perhaps more hours left after the 0855 transmission
No Worries Mates
LTM   Harry (TIGHAR #3244R)
 
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Irvine John Donald

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Re: 17:47 GMT Transmission
« Reply #43 on: February 20, 2012, 12:38:30 PM »

Harry.  In my book you're listed as a true TIGHAR believer.  I should also clarify that since there was no message from AE, Thompson should have done as much as he could to search for her. That's his job. He did leave some people on Howland.  I presume in case AE actually, miraculously, landed there. I don't know the range of his ships boats but I believe the sea state was relatively calm and he could have launched his boats in other directions. But hindsight is what we are using here. I feel some sadness for Thompson because he is all alone out there and he probably felt some responsibility for AE not getting to Howland.  Not because of what he did or didn't do but because his ship couldn't make radio contact or help AE in any significant way. Plus he has his crew to keep safe. Now he has to go find her and he can only make educated guesses based on what info he has.  Tough call.
Respectfully Submitted;

Irv
 
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Gary LaPook

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Re: 17:47 GMT Transmission
« Reply #44 on: February 20, 2012, 12:48:15 PM »

Gary was an attorney in the John Denver case? Is that correct Gary? ----
HUM
Yes.

gl
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