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Author Topic: The flight plan, magnetic course, headwinds.  (Read 473571 times)

Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #195 on: January 09, 2012, 10:25:50 PM »



Meanwhile, FWIW, I've accepted your interpretation that the 29-06 telegram from Hill to Putnam was sent at sent at 11:32 PM.  That seems a reasonable interpretation of "FA 11 32" and fits with the boilerplate on the forms that says the time that the message was received should be in the first line.
Especially with the "NL," "Night Letter" behind the time group.

 Information about two "point-to-point" stations showing the massive antenna farms needed is here and here.

gl
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Harry Howe, Jr.

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Re: The flight plan, magnetic course, headwinds.
« Reply #196 on: January 09, 2012, 10:32:08 PM »


A cursory look at Browser items on the Vidals gives some info:
Eugene Luther Vidal, Sr.(EV) was an aviator, athlete(Olympic Games competitor in the Decathalon), an ardent supporter of commercial aviation, an aeronautics instructor at West Point.  During the time of the World Flight he was Bureau Chief in the Bureau of Air Commerce within the US Dept. of Commerce.

He was a good friend of George Putnam(GPP) and Amelia(AE). Two books, East To The Dawn by Butler and Sound of Wings by Lovell suggest that He(EV) and Amelia were associated with the formation of three commercial airline companies and also had a love affair.

Eugene Luther Vidal, Jr (later known as Gore Vidal after he adopted his mother's maiden surname)(GV)  was born in 1925 and was 12 when he, according to him, heard a conversation between his dad and Putnam about the delay at Lae.
No Worries Mates
LTM   Harry (TIGHAR #3244R)
 
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #197 on: January 10, 2012, 12:39:49 AM »




Yes, I understand the difficulties of proving a negative.


So you have given this some thought, have you? ;)

gl
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Heath Smith

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Re: The flight plan, magnetic course, headwinds.
« Reply #198 on: January 10, 2012, 04:27:17 AM »


Quote
Since the leg from Lae to Howland is 2222 NM and the common estimate of DR accuracy is 10% of the distance flown then one could expect to fly the distance from Lae to Howland solely by dead reckoning and still be confident of coming within in 222 NM of Itasca and so be close enough to pick up the radio signal and track inbound to Howland. So if AE was willing to rely only on radio she didn't need Fred. But obviously they wouldn't just rely on radio.

Gary,

Thank you for the detailed information in the previous post. I have yet to read over both of your links but will check it out after work. I have a simple question about the maximum error of 10% of the distance traveled. In your above example 10% DR results in 222NM. Is this the 'total error' meaning you could be 5% North or South of your target or does this mean you could be 10% too far South or 10% too far North? For example, if you were about to start searching, are the end points to the error window 111NM to the North and 111NM to the South or is it 222NM to the North and 222NM miles to the South?

Assuming that it is 111NM North and 111NM South, and you started searching in the Northerly direction, would you travel the entire 111NM or stop short of the visibility range and turn around to go South? I am guessing on the trip South you would make the offset short of 2 times the visibility range. Would the choice of choosing an Easterly offset or a Westerly offset be arbitrary on your first pass?

Thank you in advance.

Gary,

After reading over your page I am fairly convinced that when you state "within" an amount of error, this describes a radius around the target. Using your 2222 NM and 222 NM error, this describes a circle around the target with a radius is 222 NM.

You seem pretty convinced that FN was able to get a fix at 17:42 GMT as they announced they were 200 miles out. Why is that? If FN was able to get a fix then the fact that they did not make it to Howland seems irreconcilable. I do not think we can entirely ignore the claim by Bellarts who supposedly heard AE state "cloudy and overcast" at 14:10 GMT. Perhaps we need to look at the Itasca weather log a bit closer.

As far as intercepting a LOP NW of Howland goes, it seems that they time stamps in the radio log do not allow for that. It appears that they came straight in expecting to find the Island. As Jeff pointed out, perhaps the plan really was a RDF approach but only when that did not pan out did FN take over to find Howland. AE spent quite a bit of the time on the radio either attempting to take a bearing or have Howland take bearings and she probably wasted a significant amount of time on that effort. Perhaps FN was working out a plan in the meantime but obviously whatever that plan was, it failed as well.

I am also a bit troubled as to why they would have stayed on the 157/337 line an hour after having arrived at where they thought Howland was. It makes sense that they would have started a expanding square search pattern as you suggest but this would not be the case if you were flying on the line N and S on the 157/337 LOP an hour after you had arrived. Perhaps there was not plan or knowledge of how to begin the search pattern since they were lost. Perhaps they did search and going back in the line was a last ditch effort as the fuel started to run very low.

I also read on your page the following:

Quote
There has been concern expressed that clouds could have prevented Noonan from taking star sights that late (1940 Z). They had reported flying at 12,000 feet, which normally is above most clouds. Even if some clouds where higher than 12,000 feet it is unlikely that they blocked the entire sky for hundreds of miles along the flight path.

I have never seen this 12,000ft altitude figure before. I recall outside of Lae they climbed to 10,000ft but had reduced to 8,000ft by the time they had passed Nukumanu Island. As I recall the telegrams from the guy at Lockheed Martin suggested 8,000ft as the cruise altitude. Can you point me to where this 12,000ft altitude came from?
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John Ousterhout

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Re: The flight plan, magnetic course, headwinds.
« Reply #199 on: January 10, 2012, 06:30:21 AM »

Am I the only one who jumped to the conclusion that one possible reason for AE to tell Itasca that she was flying North and South on the (157/337) line was to help them DF her position?  Her technique may have been lacking, but knowing the direction a target is moving helps establish its location to a DF station. 
She obviously didn't understand that Itasca could not get a DF bearing on her frequency. Too bad she didn't establish two-way communications when she had the opportunity.  She coulda asked questions on 3105 (am I getting louder?), and received answers on 7500 (_._ _ or _.).  All she and Fred needed was a time machine and web link to TIGHAR for answers to their navigation questions.
Cheers,
JohnO
 
« Last Edit: January 10, 2012, 06:31:53 AM by John Ousterhout »
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Martin X. Moleski, SJ

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Re: The flight plan, magnetic course, headwinds.
« Reply #200 on: January 10, 2012, 09:17:47 AM »

Too bad she didn't establish two-way communications when she had the opportunity.  She coulda asked questions on 3105 (am I getting louder?), and received answers on 7500 (_._ _ or _.).

I've started a new topic for my reply to this observation.
LTM,

           Marty
           TIGHAR #2359A
 
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #201 on: January 10, 2012, 01:29:56 PM »


"Dispatch" was the commonly used word in the newspaper industry to mean "a story sent in by a correspondent." The dispatch was received late at night on June 29th but early enough for this telegram to be send to Putnam, still on the 29th. So let's say it arrived around 10:00 p.m. New York time. Lae is 15 hours ahead of New York so the message was sent some time prior to 1:00 p.m. in Lae on June 30th, the day after Earhart had arrived in Lae.


Yes, that's possible.


American Heritage Dictionary of the English Language

(also dspch) A news item sent to a news organization, as by a correspondent.

Collins English Dictionary

journalism a report sent to a newspaper, etc, by a correspondent

Webster's New World College Dictionary, 4th Ed

a news story sent to a newspaper or broadcaster, as by a correspondent


gl
« Last Edit: January 10, 2012, 01:51:05 PM by Martin X. Moleski, SJ »
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Martin X. Moleski, SJ

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Re: The flight plan, magnetic course, headwinds.
« Reply #202 on: January 10, 2012, 01:53:44 PM »

  • (also dspch) A news item sent to a news organization, as by a correspondent.
  • journalism a report sent to a newspaper, etc, by a correspondent
  • a news story sent to a newspaper or broadcaster, as by a correspondent

None of those prevent said "news item," "report," or "news story" being phoned in.

Even granting the dictionary definition is sound (and I do grant that), people often use words in a sloppy fashion. 

The original source for the 30 June article may still be out there somewhere ...
LTM,

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Irvine John Donald

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Re: The flight plan, magnetic course, headwinds.
« Reply #203 on: January 10, 2012, 02:27:51 PM »

Is it possible that the story was radiogrammed or telegrammed to a shore station and then phoned in from there?  Could that be what was heard on the telephone?  The telegram station calling with the story rather than someone having to deliver it by paper form.
Respectfully Submitted;

Irv
 
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #204 on: January 10, 2012, 03:14:40 PM »

Is it possible that the story was radiogrammed or telegrammed to a shore station and then phoned in from there?  Could that be what was heard on the telephone?  The telegram station calling with the story rather than someone having to deliver it by paper form.
That was how telegrams were delivered near the end of the telegram era, after phone calls became cheap. Prior to that, it was less expensive to put a guy on a bicycle to hand deliver the telegram.
gl
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #205 on: January 10, 2012, 03:21:10 PM »




I also read on your page the following:

Quote
There has been concern expressed that clouds could have prevented Noonan from taking star sights that late (1940 Z). They had reported flying at 12,000 feet, which normally is above most clouds. Even if some clouds where higher than 12,000 feet it is unlikely that they blocked the entire sky for hundreds of miles along the flight path.

I have never seen this 12,000ft altitude figure before. I recall outside of Lae they climbed to 10,000ft but had reduced to 8,000ft by the time they had passed Nukumanu Island. As I recall the telegrams from the guy at Lockheed Martin suggested 8,000ft as the cruise altitude. Can you point me to where this 12,000ft altitude came from?
Thanks for pointing out that error to me, I wrote that page a long time ago. I decided to make some improvements to that section:
-------------------------------------------------------------------------


"There has been concern expressed that clouds could have prevented Noonan from taking star sights that late (1740 Z). Early in the flight they had reported flying at 10,000 feet so could have been at that altitude again later in the flight too, (or even higher since they were much lighter) which normally is above most clouds. Even if some clouds where higher than their altitude it is unlikely that they blocked the entire sky for hundreds of miles along the flight path. It has been claimed that Earhart reported at 1415 Z and again at 1515 Z "cloudy and overcast" but these words are not found in either radio log. But what is actually recorded in the radio log, more than an hour after this 1515 Z possible report of "overcast" conditions, is at 1623 Z Earhart reported "partly cloudy." There are no reports after this "partly cloudy" report so it is the most current report, in both time and location, so there is no actual evidence that the weather deteriorated later so as to prevent celestial observations. Earhart did not report descending to 1,000 feet until almost two hours later at 1818 Z.

Based on this last report of in-flight weather conditions, we can be certain that Noonan was able to take sights at 1623 Z, only two hours and forty-nine minutes before the "must be on you" transmission at 1912 Z. At that point Noonan had a large selection of celestial bodies to shoot with his octant. Almost directly in front of the plane (5° left of the nose) was the third brightest object in the sky, the planet Venus, and next to it (10° left of the nose) was the second brightest object in the sky, the Moon. Noonan didn't have to look for elusive stars darting between whatever clouds  existed at that point, it's hard not to see the moon! Because they were almost directly ahead, observations of these objects would have produced LOPs that ran approximately perpendicular to the course and so would have given them an accurate measure of the distance remaining to Howland. Off to the right, just 9° ahead of the right wingtip, was the 10th brightest star in the whole sky, Achernar. An observation of it would have produced an LOP approximately parallel to the course line and let them know if they were on course or how many miles they were off course, either to the right or to the left. In addition, there were five other, slightly dimmer, stars also positioned off to the right and left that would have also produced course line LOPs if Achernar happened to be hidden by a cloud at the moment. All of these objects were at heights that were convenient for observation. Crossing the LOP from the Moon (or Venus) with an LOP from one of the stars off to the side would have produced a fix with an uncertainty that should not have exceeded 10 NM. So looking at this as the worst case scenario, we can do the same computations as before about the uncertainty of the D.R. position at 1912 Z. In two hours and forty-nine minutes the plane would have covered 366 NM at 130 knots so the uncertainty caused by dead reckoning for 366 NM is 18 NM for the 5% estimate; 36 NM for the 10% estimate and 60 NM using the most pessimistic estimate of DR accuracy. We have to add to these estimates the original 10 NM uncertainty in a fix obtained at 1623 Z so the totals are 28 NM, 46 NM and 70 NM of uncertainty at 1912 Z. Noonan knew the time that he obtained his last celestial fix and would have used the right amount of offset to allow for the possible uncertainty."
--------------------------------------------------------
I am also going to add some more concerning the availablity of the Moon as they approached Howland, stay tuned.

gl
« Last Edit: January 10, 2012, 08:21:56 PM by Gary LaPook »
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #206 on: January 10, 2012, 07:24:34 PM »

Am I the only one who jumped to the conclusion that one possible reason for AE to tell Itasca that she was flying North and South on the (157/337) line was to help them DF her position?  Her technique may have been lacking, but knowing the direction a target is moving helps establish its location to a DF station. 
She obviously didn't understand that Itasca could not get a DF bearing on her frequency. Too bad she didn't establish two-way communications when she had the opportunity.  She coulda asked questions on 3105 (am I getting louder?), and received answers on 7500 (_._ _ or _.).  All she and Fred needed was a time machine and web link to TIGHAR for answers to their navigation questions.
Jump back.

There are three reasons that this is not supported. First, you are ascribing a level of understanding of RDF to Earhart that obviously exceeded her level of understanding. Second, that would only make sense if she kept transmitting periodically, which she didn't do. And Third, that wouldn't work.   

"KHAQQ THIS IS NRUI, WE HAVE MEASURED A BEARING TO YOUR TRANSMITTER, IT IS EITHER NINETY OR TWO SEVENTY, WE CAN'T TELL DUE TO THE ONE HUNDRED EIGHTY DEGREE AMBIGUITY INHERENT IN RDF BEARINGS, OVER,"

"NRUI THIS IS KHAQQ I WILL RUN NORTH AND SOUTH TO ALLOW YOU TO RESOLVE THAT AMBIGUITY, OVER."

" KHAQQ THIS IS NRUI, NO DO NOT DO THAT AS THAT WILL NOT RESOLVE THE AMBIGUITY. YOU MUST PROCEED IN ONLY ONE DIRECTION AND SEND ADDITIONAL  SIGNALS AFTER TEN MINUTES AND WE WILL THEN BE ABLE TO RESOLVE THE AMBIGUITY, OVER."

See attached diagram.

gl
« Last Edit: January 10, 2012, 07:47:43 PM by Gary LaPook »
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #207 on: January 10, 2012, 10:06:37 PM »



Since the leg from Lae to Howland is 2222 NM and the common estimate of DR accuracy is 10% of the distance flown then one could expect to fly the distance from Lae to Howland solely by dead reckoning and still be confident of coming within in 222 NM of Itasca and so be close enough to pick up the radio signal and track inbound to Howland. So if AE was willing to rely only on radio she didn't need Fred. But obviously they wouldn't just rely on radio.


Gary,

Thank you for the detailed information in the previous post. I have yet to read over both of your links but will check it out after work. I have a simple question about the maximum error of 10% of the distance traveled. In your above example 10% DR results in 222NM. Is this the 'total error' meaning you could be 5% North or South of your target or does this mean you could be 10% too far South or 10% too far North? For example, if you were about to start searching, are the end points to the error window 111NM to the North and 111NM to the South or is it 222NM to the North and 222NM miles to the South?

You're right, the 10% is the radius of the circle of uncertainty. Remember, you are much more likely to be near the center of the circle, near the DR position, than near the edge of the circle. The 222 radius would only apply if they DRed all the way from Lae which we know is not the case. We know they had a fix at Nukumanu island, 1,500 NM from Howland so the maximum circle radius would be 150 NM. They also had a fix over one of the ships or at Nauru which are closer, about 970 NM from Nauru, shrinking the circle further. "NOONAN MUST HAVE STAR SIGHTS" so if they couldn't get fixes then they would have turned around prior to the PNR, just short of the Gilberts, returned either to Lae or, more probably,Rabaul and try another day. We know she was mentally prepared to do this because that was part of the planning for the original leg fron Hawaii to Howland and she did turn around several times on previous legs.
(To avoid getting confused if making comparisons, keep in mind that I use nautical miles on my website but sometimes use statute miles on the TIGHAR Forum.)
Quote

Assuming that it is 111NM North and 111NM South, and you started searching in the Northerly direction, would you travel the entire 111NM or stop short of the visibility range and turn around to go South? I am guessing on the trip South you would make the offset short of 2 times the visibility range. Would the choice of choosing an Easterly offset or a Westerly offset be arbitrary on your first pass?

Thank you in advance.

I see your point, if you figured a maximum error or uncertainty in your DR is 60 NM and you had 20 NM visibility then you could aim to intercept the LOP only 40 NM out and look real hard out to the side as you approach the interception and you would then be able to see the whole 60 NM band. But, since it is much more important to be sure to find the island and not so important to save a couple of minutes (especially for Earhart as they had plenty of fuel left at that point, "Penny wise and pound foolish" comes to mind) the standard interception of the LOP is at the point of estimated maximum error and the visibility off to the side along the extended length of the LOP is taken as an additional safety margin. See standard flight navigation texts here. The same when you fly to the other end of the LOP, you go the total distance of the maximum uncertainty for the same reason before turning around to start a search pattern. 

Regarding which way to offset when starting the search pattern you would normally turn in the direction to take you to an area you haven't been through yet, if that is not the situation you normally offset into the wind, in this case to the east. But for Noonan, since they knew the wind was out of the east and they expected a smoke trail that would extend off to the west, it would be less likely that they missed to the west than that they missed to the east by overshooting the LOP because they would have had to have had a much larger error if they turned short of the LOP to miss the smoke, than if they had gone too far so they should offset to the west when returning to commence the modified square search pattern.
Quote
Gary,

After reading over your page I am fairly convinced that when you state "within" an amount of error, this describes a radius around the target. Using your 2222 NM and 222 NM error, this describes a circle around the target with a radius is 222 NM.

You seem pretty convinced that FN was able to get a fix at 17:42 GMT as they announced they were 200 miles out. Why is that? If FN was able to get a fix then the fact that they did not make it to Howland seems irreconcilable. I do not think we can entirely ignore the claim by Bellarts who supposedly heard AE state "cloudy and overcast" at 14:10 GMT. Perhaps we need to look at the Itasca weather log a bit closer.


Yup, whether they got the last fix at 1623 Z ("partly cloudy") or as late as 1740 Z, Noonan would have planned a sufficient offset to allow for the maximum likely DR error in the leg from that fix to the interception point. That is the whole point of the landfall procedure, to cure any inaccuracy in the DR. So yes, it makes no sense that they didn't find Howland.

Quote

As far as intercepting a LOP NW of Howland goes, it seems that they time stamps in the radio log do not allow for that. It appears that they came straight in expecting to find the Island. As Jeff pointed out, perhaps the plan really was a RDF approach but only when that did not pan out did FN take over to find Howland. AE spent quite a bit of the time on the radio either attempting to take a bearing or have Howland take bearings and she probably wasted a significant amount of time on that effort. Perhaps FN was working out a plan in the meantime but obviously whatever that plan was, it failed as well.

Keep in mind, those radioed distances were not exact. It makes sense that they headed directly towards Howland, expecting to home in on Itasca's radio signal when they came within range. But they would have recognized that there was some problem with this plan when they couldn't receive the radio signal at the point that they expected to, let's say about 200 NM out. At that point, or shortly after that, Noonan would start the backup plan to do the landfall procedure. The earlier you turn off the direct course to aim for the interception point, the fewer extra miles you have to fly so they would not have delayed this turn unnecessarily. There was little downside to doing this because, if on the way to the interception point, they then started to receive the radio signal, they could turn immediately to home on the station after adding very few extra miles to their flight path.
Quote

I am also a bit troubled as to why they would have stayed on the 157/337 line an hour after having arrived at where they thought Howland was. It makes sense that they would have started a expanding square search pattern as you suggest but this would not be the case if you were flying on the line N and S on the 157/337 LOP an hour after you had arrived. Perhaps there was not plan or knowledge of how to begin the search pattern since they were lost. Perhaps they did search and going back in the line was a last ditch effort as the fuel started to run very low.


The only way I can make sense out of this statement is that they were flying a modified search pattern with longer legs parallel to the LOP and shorter legs perpendicular to it. Earhart might say that she was flying north and south "on the LOP" when on one of these long parallel legs.

gl
« Last Edit: January 13, 2012, 03:08:21 AM by Gary LaPook »
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #208 on: January 10, 2012, 11:57:40 PM »


I can agree that if true it would support that NR16020 should have been above most clouds.  But that's also a fairly stout altitude for cruising hours on end, especially at night - the concern would be with crew physiology. 

Had AE and FN good reasons (like perhaps to obtain celestial shots) they might well have done so (and if they said they did, I'd agree they must have).  It just seems odd that they would do that for any extended period of time, so I too would like to know the source of the "12,000 ft" reference for the flight that night.  It would also be useful to understand for how long they may have been at that altitude, if it can be known.

Here are a couple of useful links about flying at atitude -

"The 91 Percent Solution"

"Oxygen Issues for General Aviation Pilots..."

LTM -
And current regulations require that the pilot use oxygen anytime the cabin altitude is above 14,000 feet and also after 30 minutes above 12,500 feet. You must make oxygen available to the passengers above 15,000 feet. I remember deadheading in an empty plane and I took it up to 17,500 feet without oxygen. It was a Sunday and I was reading the Sunday comics section of the newspaper, and boy were they hilarious!

When I was preparing to parachute from 30,000 feet I went to Wright-Patterson AFB and rode their altitude chamber up to 35,000 feet where we took our masks off and tried to do various math problems on a piece of paper and the results were also quite funny. The best part of the ride was the explosive decompression demonstration. They brought the small section of the chamber down to 8,000 feet and then took the large section up to 40,000 then they popped the connecting door open and we were instantly at 30,000 feet. The chamber fills instantly with fog because the moisture condenses out with the sudden reduction in pressure and everybody "out-gasses." Then you put your mask on before you pass out. Lots of fun.

You can buy an oxygen monitor that clamps on your finger at your local drug store for about fifty bucks, or here.

gl
« Last Edit: January 11, 2012, 12:41:11 AM by Gary LaPook »
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Gary LaPook

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Re: The flight plan, magnetic course, headwinds.
« Reply #209 on: January 11, 2012, 01:52:41 AM »

Well, not so fast.

All of my research confirms that there was no telephone service, either by undersea cable or by radiotelephone, from Lae to the outside world in 1937. Even local radio telephone service in New Guinea did not come on line until 1939.

What is the source of the image?



Purdue.

gl
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