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Author Topic: Odds of Spotting Survivors from the Air  (Read 126080 times)

Gary LaPook

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Re: Odds of Spotting Survivors from the Air
« Reply #30 on: November 14, 2011, 01:24:28 AM »

Gary forgot to attach the definitions from page 150 of the CAP manual.  Here they are:

Meteorological Visibility - the maximum distance at which large objects, such as a mountain, can be seen.

Scanning Range - the lateral distance from a scanner's search aircraft to an imaginary line on the ground parallel to the search aircraft's ground track. Within the area formed by the ground track and scanning range, the scanner is expected to have a good chance at spotting the search objective. Scanning range can be less than but never greater than the search visibility.

Search Visibility - the distance at which an object on the ground (CAP uses an automobile as a familiar example) can be seen and recognized from a given height above the ground. Search visibility is always less than meteorological visibility. [Note that on the POD chart that the maximum search visibility listed is four nautical miles.]


I interpret this to mean that Search Visibility changes based upon the size of the object. CAP uses an automobile as a familiar example.  At best, you can see a car on the ground from four miles away. That's why the maximum search visibility listed is four nautical miles.  Scanning Range is much more specific and is "the lateral distance from a scanner's search aircraft to an imaginary line on the ground parallel to the search aircraft's ground track."

If anything is proved by all this it's that the CAP POD tables do not contemplate a search for anything smaller than a car.  Most people are smaller than most cars.
-----------------------------
Just for you Ric, I am attaching page 74 from the CAP manual since it appears to apply to you.

"Scanning range sometimes may be confused with search visibility..."

gl
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John Ousterhout

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Re: Odds of Spotting Survivors from the Air
« Reply #31 on: November 14, 2011, 06:43:40 AM »

Considering the large number of motorcycle accidents caused by car drivers who "didn't see the motorcycle", Gary's example also illustrates the common problem of preconception on the part of the search person.  Car drivers are expecting to see something that looks like a car when they are watching for a gap in traffic (as one common scenario).  When the gap in the stream of cars arrives, they accelerate through it, not noticing that a motorcycle is in that "gap".  The motorcycle doesn't register at all.  I've witnessed this many times as a motorcyclist.
The relevance to the discussion is the question "what were the searchers expecting to see"?  I doubt we can answer this question, given what little we know.  I think it safe to assume they would have been likely to have noticed an aircraft, and might have been looking for one as the principal indication of EA/FN present on an island or reef.  The searchers mention that Gardner Island was covered with "low bushes and trees" (please correct my memory if this quote is inaccurate) when in fact the bushes and trees were very large.  This may indicate a mistake in perceived scale that would have been likely to fool an observer looking for people.  A person on the beach would appear much smaller than expected, making them less likely to be noticed.
Also, a person on the west side of the island might be hidden in the morning tree shadow.  Wasn't the flight about 09:00?  How much of the western beach was in full sunlight at that time?  Might a person on the beach know it was important to stand in the sun in order to be seen, or would they make th emistake of standing in the shade waving their arms?
Cheers,
JohnO
 
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Friend Weller

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Re: Odds of Spotting Survivors from the Air
« Reply #32 on: November 14, 2011, 08:33:26 AM »

Considering the relationships of scale, consider this paraphrased exchange between a friend of mine meeting his father at the Salt Lake International Airport many years ago.  Both were college-educated and worked in geology-related fields.  His father was visiting the west for the first time: 

"Jeff, tell me, what kind of moss is that on the hills?

"Ummm, Dad, those are trees on the mountains...."

LTM,
Friend
Friend
TIGHAR 3086V
 
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Gary LaPook

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Re: Odds of Spotting Survivors from the Air
« Reply #33 on: November 14, 2011, 12:08:54 PM »

Quote from: Ric Gillespie on November 13, 2011, 09:02:03 AM

    Gary forgot to attach the definitions from page 150 of the CAP manual.  Here they are:

    Meteorological Visibility - the maximum distance at which large objects, such as a mountain, can be seen.

    Scanning Range - the lateral distance from a scanner's search aircraft to an imaginary line on the ground parallel to the search aircraft's ground track. Within the area formed by the ground track and scanning range, the scanner is expected to have a good chance at spotting the search objective. Scanning range can be less than but never greater than the search visibility.

    Search Visibility - the distance at which an object on the ground (CAP uses an automobile as a familiar example) can be seen and recognized from a given height above the ground. Search visibility is always less than meteorological visibility. [Note that on the POD chart that the maximum search visibility listed is four nautical miles.]

    I interpret this to mean that Search Visibility changes based upon the size of the object. CAP uses an automobile as a familiar example.  At best, you can see a car on the ground from four miles away. That's why the maximum search visibility listed is four nautical miles.  Scanning Range is much more specific and is "the lateral distance from a scanner's search aircraft to an imaginary line on the ground parallel to the search aircraft's ground track."

    If anything is proved by all this it's that the CAP POD tables do not contemplate a search for anything smaller than a car.  Most people are smaller than most cars.

Note, the definition of "search visibility" says "the distance at which an object on the ground (CAP uses an automobile as a familiar example) can be seen and recognized from a given height above the ground." It DOES NOT say "the distance at which an object on the ground (CAP uses an automobile as a familiar example) can be seen and recognized from a given distance." So your assertion that the CAP considers 4 mi as the distance that a car sized object can be spotted is disproved by the definition itself.

Andrew pointed me to this reference:

http://www.cap-es.net/NESA%20MAS/Aircrew%20Chapter%209%20-%20Search%20Planning%20and%20Coverage.ppt

and I am attaching the definitions slide from there. You will note in this reference there is no mention of an automobile in the definition of "search visibility" so there is no reason to think that the distance that you can see an automobile is taken as any kind of standard for determining "search visibility."
gl

https://tighar.org/smf/index.php?action=dlattach;topic=508.0;attach=311
* Aircrew Chapter 9 - Search Planning and Coverage-1.pdf (89.08 kB - downloaded 3 times.)
« Last Edit: November 14, 2011, 01:46:03 PM by Martin X. Moleski, SJ »
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Gary LaPook

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Re: Odds of Spotting Survivors from the Air
« Reply #34 on: November 14, 2011, 12:13:25 PM »

Considering the large number of motorcycle accidents caused by car drivers who "didn't see the motorcycle", Gary's example also illustrates the common problem of preconception on the part of the search person.  Car drivers are expecting to see something that looks like a car when they are watching for a gap in traffic (as one common scenario).  When the gap in the stream of cars arrives, they accelerate through it, not noticing that a motorcycle is in that "gap".  The motorcycle doesn't register at all.  I've witnessed this many times as a motorcyclist.
The relevance to the discussion is the question "what were the searchers expecting to see"?  I doubt we can answer this question, given what little we know.  I think it safe to assume they would have been likely to have noticed an aircraft, and might have been looking for one as the principal indication of EA/FN present on an island or reef.  The searchers mention that Gardner Island was covered with "low bushes and trees" (please correct my memory if this quote is inaccurate) when in fact the bushes and trees were very large.  This may indicate a mistake in perceived scale that would have been likely to fool an observer looking for people.  A person on the beach would appear much smaller than expected, making them less likely to be noticed.
Also, a person on the west side of the island might be hidden in the morning tree shadow.  Wasn't the flight about 09:00?  How much of the western beach was in full sunlight at that time?  Might a person on the beach know it was important to stand in the sun in order to be seen, or would they make th emistake of standing in the shade waving their arms?
--------------------------
You are absolutely right that car drivers don't see motorcycles because they are not looking for them. My experiment suffered from this same problem, I was not looking for motorcycles yet I first spotted it a .5 miles. If my goal had been to spot motorcycles I most likely would have noticed him even further away.

gl
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richie conroy

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Re: Odds of Spotting Survivors from the Air
« Reply #35 on: November 14, 2011, 04:24:35 PM »

so would the writeing on side of plane be readable to some 1 on the ground ? at that height ?

i ask this because if amelia were'nt to expect an Air search then what if the planes were Japanese an seen her an took her hostage ?

so decided to wait for a ship but it turned out to late ?
 

We are an echo of the past


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richie conroy

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Re: Odds of Spotting Survivors from the Air
« Reply #36 on: November 14, 2011, 04:33:40 PM »

<h2>A TRAGEDY OF THE PACIFIC</h2><iframe src="http://www.britishpathe.com/embed.php?archive=7439" name="pathe_flash_embed" width="352" height="264" scrolling="no" frameborder="1"><p>Your browser does not support iframes.</p></iframe>

also on 1.19:44 ov this video wen the view from plane was on ships, u can see ships but u cant see planes on the ships ?

what height can we ashume the planes are ?
We are an echo of the past


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Gary LaPook

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Re: Odds of Spotting Survivors from the Air
« Reply #37 on: November 14, 2011, 04:49:26 PM »

so would the writeing on side of plane be readable to some 1 on the ground ? at that height ?

i ask this because if amelia were'nt to expect an Air search then what if the planes were Japanese an seen her an took her hostage ?

so decided to wait for a ship but it turned out to late ?
-----------------------------
December 7, 1941, is four and a half years after Earhart disappeared. No reason to fear the Japanese since her original plan was to land in Tokyo. Phoenix islands are nowhere near the Japanese Mandated Islands so no reason or ability for Japanese planes fly that far, the nearest is Mili one thousand nautical miles away from Gardner. Even if Japanese planes came off of a carrier there was no reason for the Japanese to be mad at Earhart since Gardner is not a Mandated island so no reason to think Earhart was a spy.

gl

gl
« Last Edit: November 14, 2011, 04:52:37 PM by Gary LaPook »
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richie conroy

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Re: Odds of Spotting Survivors from the Air
« Reply #38 on: November 14, 2011, 05:31:36 PM »

dont matter the dates the japenese cud ov been secretly makeing maps of the islands in case of war ?

an ur answer dont answer my other question of how high the plane was in that video ?

also this is for Ric  "almost lost Ric in the -- uh -- guano pit that occupies the middle of the island, otherwise found nothink"

McKean Island haha  :)
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richie conroy

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Re: Odds of Spotting Survivors from the Air
« Reply #39 on: November 14, 2011, 05:32:49 PM »

what is it wid u an pits lol  :)
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richie conroy

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Re: Odds of Spotting Survivors from the Air
« Reply #40 on: November 15, 2011, 09:54:00 AM »

dont matter the dates the japenese cud ov been secretly makeing maps of the islands in case of war ?

an ur answer dont answer my other question of how high the plane was in that video ?

also this is for Ric  "almost lost Ric in the -- uh -- guano pit that occupies the middle of the island, otherwise found nothink"

McKean Island haha  :)
sorry didnt mean this to sound like i was being funny i just tend to type how i speak  :)
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Ric Gillespie

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Re: Odds of Spotting Survivors from the Air
« Reply #41 on: November 15, 2011, 10:19:03 AM »

I think we should re-title this thread "Interminable Flogging of Dead Horses."
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Bruce Burton

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Re: Odds of Spotting Survivors from the Air
« Reply #42 on: November 15, 2011, 02:10:22 PM »

I think we should re-title this thread "Interminable Flogging of Dead Horses."

I second the motion.  :)
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Gary LaPook

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Re: Odds of Spotting Survivors from the Air
« Reply #43 on: November 15, 2011, 03:54:21 PM »

I think we should re-title this thread "Interminable Flogging of Dead Horses."
----------------------------

Sure, we have both stated our positions clearly, others can read it and make up their own minds.

What is interesting is how we each approach this issue and the many other issues we have discussed over the last 9 years. I am a skeptic, I have serious doubts about your theory (I have much more serious doubts about the various Japanese capture theories though.) So when I see information that calls into doubt theories about the disappearance, such as the POD tables, I use it to evaluate the theory. Since the POD tables show a high cumulative probability that they should have been spotted IF they had been on the island, this just increases my doubts about your theory. You, on the other hand, KNOW, in your heart of hearts,  that Earhart was on Gardner so the search, no matter how thorough or professional must have missed seeing them for some reason, hiding in the bush, couldn't get to the beach in time, the pilots were untrained, drunk, blind, misapplying the POD tables, etc., always some way to explain away anything that doesn't comport with your certain knowledge that Earhart was on Gardner. After all, there must be something wrong with the search because Earhart WAS THERE.

I hope you are successful in finding indisputable evidence that actually proves your theory, I would like to know the answer to this mystery before I die, so good luck.

gl
« Last Edit: November 15, 2011, 03:59:35 PM by Martin X. Moleski, SJ »
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Ric Gillespie

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Re: Odds of Spotting Survivors from the Air
« Reply #44 on: November 15, 2011, 05:07:51 PM »

You, on the other hand, KNOW, in your heart of hearts,  that Earhart was on Gardner so the search, no matter how thorough or professional must have missed seeing them for some reason, hiding in the bush, couldn't get to the beach in time, the pilots were untrained, drunk, blind, misapplying the POD tables, etc., always some way to explain away anything that doesn't comport with your certain knowledge that Earhart was on Gardner. After all, there must be something wrong with the search because Earhart WAS THERE.

My belief that Earhart was there has nothing to do with my heart of hearts (there are many who would testify that I don't have one).
I am convinced by the abundant evidence - archival, photographic, physical, and anecdotal - that she was there.  You are not.  It's as simple as that.
As you say, others can make up their own minds.
 
   
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