Getting my head around ACARS

cjnewson88

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cjnewson88
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Oct 19, 2011
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Every now and again I've seen the ACARS claim pop up from P4T claiming UA175 received a message 20 minutes after it had hit the South Tower. It all seems to stem from this;

331321151.png


According to P4T, the time stamp at the top is the date/time the message was sent, and the time stamp at the bottom is the date/time where it was received by the aircraft, in this case, by UA175 at 1323 UTC (0923 ET).

So, trying to get my head around this, I have a couple of questions for anyone familiar with this system. First;

1. Does the last line indeed time stamp when the aircraft receives the message? Or is this a point that P4T are wrong on?

2. Do the transmitting stations automatically change based on the flight plan of the aircraft, or if not, how does ACARS determine which ground station to transmit from?

3. Was there any second track or flight plan UA175 put into the system, in the same way AAL11A was put in after its hijacking? Or did one automatically create when UA175 switched its transponder code?

Trying to get my head around it. I've read through past threads here, but they seem to be a mess.

Cheers.
 
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I'm not sure what I'm looking at (I'm on my phone) but going on the notion that there is a timestamp there, its an interesting question. Just guessing but perhaps the second timestamp indicates when the network stopped attempting to send the message to UA175 after being unable to make contact. With the various components involved in flight constantly requiring up-to-date information, I could see a time limit being placed on the sending/receiving of text information. The informationin the message might no longer be relevant by the time it is received and could cause confusion. An example: where I live, I often hit cell dead zones including while inside my home. Often, as I drive to work I get swamped with text messages as I exit a dead zone. My phone only gives the time I received them so some messages are no longer relevant and cause confusion. "Oh you mean that invite to hit the pub was for last night, not tonight?"
 
Blaupunkt69 said:
I'm not sure what I'm looking at (I'm on my phone) but going on the notion that there is a timestamp there, its an interesting question. Just guessing but perhaps the second timestamp indicates when the network stopped attempting to send the message to UA175 after being unable to make contact. With the various components involved in flight constantly requiring up-to-date information, I could see a time limit being placed on the sending/receiving of text information. The informationin the message might no longer be relevant by the time it is received and could cause confusion. An example: where I live, I often hit cell dead zones including while inside my home. Often, as I drive to work I get swamped with text messages as I exit a dead zone. My phone only gives the time I received them so some messages are no longer relevant and cause confusion. "Oh you mean that invite to hit the pub was for last night, not tonight?"
Click to expand...

There are several interpretations of the second timestamp, none of which have anything to do with the time UAL175 "received" the message. Yours is one. It is also a printed copy, so it could be the time the message was printed. It could be a transit timestamp through the system, so where the first timestamp is the time it was entered into the system, the second is the time it hit the network for transmission. One thing is likely: When taking odds whether PffffffT's interpretation is correct or not, I will always bet against them.
 
CJ, IIRC, most of the acars debunking didn't actually happen here at jref, it happened in a thread over at unexplained-mysteries. One of the members over there spent the money and bought the literature explaining how the system works from the company that operates it. I'll see if I can go find the old thread and link to it here.

Hopefully Reheat will show up in this thread sometime soon, he probably has the best grasp on the subject of acars on this board. I won't be of much help because I never really had a good understanding of it and what little I learned, I've already forgotten.

In an extremely rare display of humility, Captain Bob locked the thread down at his forum because the authors couldn't "get their stories straight." It Captain Bob is willing to admit that a crazy conspiracy theory is wrong, then that should be a pretty good indicator that it actually is.



ETA: Reheat provided the original link to the unexplained mysteries forum in a previous thread. Below is the link. I hope it helps.
http://www.internationalskeptics.com/forums/showpost.php?p=7853893&postcount=57
 
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Boone 870 said:
ETA: Reheat provided the original link to the unexplained mysteries forum in a previous thread. Below is the link. I hope it helps.
http://www.internationalskeptics.com/forums/showpost.php?p=7853893&postcount=57
Click to expand...

Just noticed this thread. Someone has to wake me if there is an issue with which I can help.. I'm here daily, but usually somewhere else in the forum as this specific sub-Forum is about dead..

This is typical ballsucker stuff. How many times has Woody Box lead him and his idiots down the path to what should be embarrassment for normal people? This is simply another in the long list of charades in which they've engaged chasing stuff that more knowledge and more common sense should have precluded. No surprise as all they have and all they ever had was misinformation, spurious speculation, or outright lies from the beginning.
 
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