ACARS Confirms 9/11 UA 175 Aircraft Was Airborne Long After Crash! Just WOW!

reply to post by snowcrash911


Yes, thank you for confirming what I had pointed out earlier, in this thread:

....quoting from the interview with Michael J. Winter:

Mr. Winter explained the Aircraft Condition and Reporting System ACARS uses radio ground stations RGS at various locations throughout the United States for communication. The messages from the aircraft utilize the RGS in a downlink operating system. A central router determines the strongest signal received from the aircraft and routes the signal/message to UAL flight dispatch.

(Please note also, as I previously mentioned, the mistake in the actual terminology of the acronym 'ACARS'. Is this sloppy work of or by the person who transcribed Mr. Winter's comments?)

The thing is, that describes downlink, not uplink.

Again, correct.


Re: the last bit (not re-posted here):

That last sentence is confusing: it doesn't actually mean "confirmation", it connotes the origin of the message, but it can be (deliberately) misconstrued to mean "confirmation", and that's what I think happened.

I think what I'm on to here is the anatomy and the genesis of P4T's article.

Yes. Precisely.

Originally posted by ProudBird
reply to post by snowcrash911

 

Yes, thank you for confirming what I had pointed out earlier, in this thread:

I think I must have overlooked or forgotten that, sorry. I guess we're on the same page then.

I think you guys are getting to the heart of it now.

The way I see it is in regular flights the ACARS sends it's position report every 10 minutes as stated, the ARINC system tracks this and continually routes the up links to the correct station.

The question is what does the ARINC system do when it stops receiving the position down link? I don't know, but would guess that being as how its a program that it would follow a normal routine, for example checking the stations farther along the planned route, or at least the direction of flight. Uplinks are lost, not frequently but sometimes, I would imagine that there would be a trouble shooting part built into this multimillion system which would attempt to reconnect with the airplane.

Sorry have to stop in mid thought, got something I need to deal with

I also love how you can fill in the blanked out sections in one document with information from the other, or from external sources. What difference does it make to blank out a portion of the document containing the squawk code for hijack, which everybody knows is 7500?

Or... where the name of the dispatcher who sent the ACARS message "I heard of a reported incident" is blanked out in the MFR but clearly identifiable as UAL San Francisco maintenance David Price in the FBI 302 (PDF page 33)...

Something else:

Knerr provided a cursory explanation of how ACARS works. All such communications are routed through a contracted service provided by AIRINC. That service is simply a transmission service consisted on some 300 ground stations throughout the United States. Dispatchers type in a free text message at their terminals and the AIRINC transmission service converts that message into a standardized air-ground format that is then sent to the plane. The message is received on a small terminal screen in the aircraft and can be printed out. There are two forms of acknowledgement [sic]; an automatic avionics acknowledgement [sic] that the message reached the plane and a crew acknowledgement [sic] that the crew has actually seen the message. Not all messages require the latter acknowledgement [sic].

Source

So, according to Knerr, there is an automatic avionics acknowledgment, the question is, IF Knerr is technically correct, where is that acknowledgment stored? We already know the date/time at the bottom references telex printer times; which means we apparently don't have the actual acknowledgment information in the FOIA data.

P4T list the ACARS message by Rogers in their article, and it contains what P4T claims to be the "time of receipt" by UA 175, but the MFR claims this message wasn't received. Therefore, either we have additional confirmation that the time stamp below doesn't reflect a receive confirmation, or Knerr's data disagrees with the notion that it wasn't received. Given what we've seen in this thread, and given that we know UA 175 crashed into WTC 2 from other evidence, it's the former. But, I'd prefer it if this was nailed down unforgivingly, knowing who we're dealing with.That's the crux of the matter. P4T feasts off confusion.

First part

Originally posted by snowcrash911

Originally posted by bubs49
The Memorandum for the Record is a document released by the 9/11 Commission, therefore it is not a straw man argument to identify the Commission as its source.

Oh. Well in that case, when you cite Ballinger from the same document, you should "identify the Commission as its source" as well. Why the double standard?

The same document??? Oh my God…
OK, let's start from the basics then. The document you took the quote "1303:17 Rogers-initiated message not received by the aircraft" from is MFR 04017215. These are the minutes from various sessions of the Commission from November 17 to November 21, 2003. David Knerr was only one of the participants. Other managers from United Airlines and American Airlines in key roles were also present. This is clearly specified at the very beginning.

Ballinger's quote is taken from MFR 04020009. The date is April 14, 2004. That session was an interview exclusively to Ed Ballinger, not other people.
Two different sessions, two different dates, two different documents. Although both are called Memorandum for the Record, they are two separate documents. Both come from the Commission, both were released by the Commission, however they are clearly not the same document.

Originally posted by snowcrash911

Originally posted by bubs49
Unlike FBI302, who contains interviews by the FBI to several people, among then David Knerr and Michael J Winter, the Memorandum for the Record is not a direct interview to Knerr.

There is no difference. In both cases, there is an interviewer and an interviewee, wherein the interviewee is referred to in the third person by the interviewer.

Completely false. There is huge difference.
Let's take a look at the very beginning from MFR 04020009:

Event: Ed Ballinger, former United Airlines flight dispatcher
Type: Interview

Clearly it is an interview, clearly it is an interview only to Ed Ballinger.
Now let's take a look at the very beginning from MFR 04017215:

Event: Interviews of United Airlines and American Airlines personnel in key roles on September 11, 2001
Type: Site visit

First, it is not an interview. Second, it is a "site visit". Again, David Knerr was only one of the participants.

Originally posted by snowcrash911

Originally posted by bubs49
Also, the Commission focused only on "messages of interest" and, for whatever reason, decided to ignore others. Knerr was obviously present at that session and we may also speculate he was the source for "The last message (1303:17Z) was not received"

False. There is no speculation. Knerr is the source. Knerr is identified as the provider of the data and the briefing. I quote:

David Knerr, Manager, Flight Data Automation, provided the briefing. Knerr stated that he accomplished an "ACARS audit" on 9-11 on both UA 175, and UA 93 "by noon." He verbally certified that he presented to Mr. Kara in compiled form all of the ACARS information relevant to both flights that day.

Source

Period.

Thank you for quoting that relevant part of the "ACARS" section from MFR 04017215. Now please tell me where is Knerr referenced in the following sections "United Flight 175 messages of interest", "United Flight 93 messages of interest", "Aircraft Situation Display (ASD)" and "Other Items". It is your speculation that Knerr is the source. There is no indication such as "Mr Knerr said that Flight 175…".
Also please note that the in following section, called "Aircraft Situation Display (ASD)", American Airlines is also referenced and it is clear that this information can not come from David Knerr, which was Manager, Dispatch Automation at UNITED AIRLINES INCORPORATED UA at that time.

MFR 04017215 is not a direct interview to David Knerr. Period. I am open to admit he was the source for "1303:17 Rogers-initiated message not received by the aircraft", but you have no evidence to prove that it was his decision to remove a lot of relevant messages to/from United 175 and United 93 from that document. This is why I said and confirm that MFR 04017215 is a document coming from the Commission and not from Knerr. And you have no basis to disprove my claim.

Second Part

Originally posted by snowcrash911

Originally posted by bubs49
however the MFR is not an affidavit or a document by David Knerr.

Neither is an FBI 302.

I quote:

An FD-302 form is used by FBI agents to "report or summarize the interviews that they conduct" [3][4] and contains information from the notes taken during the interview by the non-primary agent.

It consists of information taken from the subject, rather than details about the subject themselves.

A forms list from an internal FBI Website lists the FD-302 as Form for Reporting Information That May Become Testimony.

Source

Unfortunately for you, all this supports my claim, not yours. FBI302 is the transcription of interviews made by the FBI to many people, among them David Knerr and Michael J Winter. MFR 04020009 is the minutes from the Commission's session on April 14, 2004, which was an interview to Ed Ballinger as clearly specified at the very beginning ("Type: Interview").
Instead, MFR 04017215 is not an interview to David Knerr ad explained above. You are wrong again.

Originally posted by snowcrash911

Originally posted by bubs49
I remind you that Knerr declared to the FBI in 2002 that United 93 kept on receiving messages until 10:12 EDT and only after that time the ACARS uplinked by the airline were rejected.

Thanks for the reminder. I read the document. Here's what Knerr said, I quote:

In the final moments, at 10:12 AM EST, of UA FLIGHT 93's flight, ACARS messages were being sent from ground communications but were not being received. This was causing the ACARS messages to be rejected. KNERR advised that FLIGHT 93's low altitude may have caused this dilemma or the fact that FLIGHT 93 had already crashed at the time the messages were sent.

Source

Nowhere in there does Knerr "declare" anything you say he did, except if you allow yourself some creative interpretation, which, clearly you do. Not only is 10:12 erroneously referred to by the FBI as Flight UA 93's "final moments", all Knerr is stating is that at that time, messages were to UA 93 were being rejected, not that they had successfully arrived before that. FBI gets the time wrong, and Knerr doesn't say what you claim he does.

You clearly ignore this subject, my friend. Knerr's statement fully corroborates Winter's statement from the same document:

Messages #18 and #19 were sent to the aircraft from CHIDD using the RGS near Champaign, IL CMI as designated in the line "AN N591UA/GL CMI...". Both messages were sent to the printer and Message #19 also activated an audible signal in the aircraft.

Here are the messages Winter is referring to:

DDLXCXA CHIAK CHI68R
.CHIAKUA 111410/ED
CMD
AN N591UA/GL CMI
- QUCHIAKUA 1UA93 EWRSFO
- MESSAGE FROM CHIDD -
DO NOT DIVERT TO DC AREA
CHIDD ED EALLINGER

;09111410 108575 0706


DDLXCXA CHIAK CHI68R
.CHIAKUA 111410/ED
CMD
AN N591UA/GL CMI
- QUCHIAKUA 1UA93 EWRSFO
- MESSAGE FROM CHIDD -
DO NOT DIVERT TO DC AREA
CHIDD ED BALLINGER

;09111411 108575 0707

Messages #20 to #24 were sent to the aircraft from CHIDD. However, all of the messages were rejected indicating the aircraft did not receive them.

Here is an example of the last failed uplinks to UA93 Winter is referring to (Messages #20 to #24):

CHIAO CHI68R
.CHIAOUA 111420/ROB
CMD
AN N591UA/GL DEC
- QUCHIAOUA 2
DDLXCXA
***UA93 EWRSFO***


There is no room for speculation, nor for interpretation. Winter declares that messages #18 and #19 were received by the aircraft and United 93 was over Champaign, IL at that time. Note the transmitting RGS (CMI), note the timestamp (14:10 Z, i.e. 10:10 EDT). Received and confirmed by Winter.
Note finally how this perfectly matches Knerr's statement:

In the final moments, at 10:12 AM EST, of UA FLIGHT 93's flight, ACARS messages were being sent from ground communications but were not being received. This was causing the ACARS messages to be rejected. KNERR advised that FLIGHT 93's low altitude may have caused this dilemma or the fact that FLIGHT 93 had already crashed at the time the messages were sent.

In fact, the message sent by UAL at 14:20Z (10:20 EDT) was not received.

There is no room for skirting around here and refute evidence backed by official documents. Knerr's statement corroborates Winter's statement. Both UAL managers confirm that United 93 was still airborne at least until 10:10 EDT at more than 350 nm from Shankville. There is no way such ACARS could possibly be received by United 93 if United 93 were actually in Shanksville as the official version claims. The max. coverage area of an RGS is 200 miles.

Third part

Originally posted by snowcrash911

I'm not sure what your point is. Since you guys claimed in the past, using the flight explorer video from MSNBC, that UA 175 flew northeast of NYC after its crash, have you figured out yet which data set you'd prefer to mislead your supporters with?

My point is that there is full and solid evidence that United 93 was airborne and far from the alleged crash site and that United 175 was far from New York at 9:23.

Your post contains a lot of mistakes, inaccuracies and speculation. Nothing you or others presented here so far disproves Pilots for Truth's claim.

Originally posted by gman1972

Originally posted by ThePostExaminer

Ballinger worked through the ACARS messages for the FBI as seen in the ACARS PDF. Are you really trying to tell us that this guy's "opinion" isn't worth taking into consideration over yours (whatever it is now) and gman's??

I don't have an opinion examiner, I am sharing my knowledge on the subject and my access to be able to share it. I invited people to teach me something that I may not know. Not sure why you guys keep dragging me though the mud, I haven't said one bad, condescending, aggressive, or otherwise remark this whole time.

Geese even when i was misquoted I didn't come out with, "obviously you can't read" or "Please reread what I wrote you obviously didn't pay attention." or any of the other common remarks.

Can you guys just calm down a bit so we can have a rational discussion on this?

Gman, I think that was the first post that I've addressed directly to you. I don't see how you find it "aggressive" or how I'm dragging you "through the mud". As I said in the post, I wasn't sure whether you or Proudbird made the "backlog" remark. It was you wasn't it?

You've stated that the timestamp at the bottom of the printout "definitely" isn't "time received". That's about as finite as it gets, no?

I agree (and always hope) that these issues can be discussed rationally That's why I want to narrow the parameters of the argument instead of everybody putting their doots up!

1. As for the second timestamp being the "printer", what logical purpose does it serve to know what time it was printed??

2. When you said that the printer takes "one or two minutes"...I've read on a ARINC newssheet from 2000 that the messages can range from 15-30 seconds to 1-2 minutes to reach the aircraft. This matches the majority of ACARS messages linked to in the PDF, doesn't it? And why would a printer take 1-2 minutes within a self contained office?

There's also this quote from a dispatcher at airline.net from 2007

And ACARS messages are fast. Out of my office window I can see aircraft departing from 19R at ARN. When the aircraft lifts off ACARS sends the off message. VHF to the local ACARS transceiver at ARN, then landline to our base at LHR, then back to my printer as a MVT message. I hear the printer clack out a MVT msg and look up and see the A319 at 100ft on departure. It is also useful when they arrive. I don't have to meet aircraft, just be ther a few minutes later. So I can relax in the office and wait till the arrival ACARS msg arrives on the printer. They all make exactly the same sound so I can tell it is a MVT msg from across the room. Then I put my coat on and get in the van.

I know it's an automated response from the aircraft to ground control, but the guy is obviously saying that there is an interaction between a message sent and the printer. Acknowledgement.

3. Again I ask you (apologies if you've answered this already) to read through the points I raised, especially regarding the logic of ground control sending a message that may entail a request for immediate diversion, for example, and the apparent claim being made here that ground control doesn't know whether the message has been received or not. That's what your basically saying, right?

Cheers

Originally posted by ThePostExaminer
Proudbird, nice cherrypicking of my points. Particularly the section I clearly stated were "my 2cents".
There's no need for "us" to contact Ballinger regarding his claims that the timestamps refer to time sent/time received. You're claiming he is wrong. No if, no buts, he's simply wrong according to GLs.

Let's see if you can respond to the points that you omitted.

1. You say that Ballinger was merely stating "his opinion" in that the timestamps referred to time sent and time received, yet we should take your (still retracted?) "opinion" which is based on the latest most spinnable claims until the next one comes along?

Ballinger worked through the ACARS messages for the FBI as seen in the ACARS PDF. Are you really trying to tell us that this guy's "opinion" isn't worth taking into consideration over yours (whatever it is now) and gman's??

2. What's being said here? That a communications system which is used for many purposes which range from the relatively "mundane" to timesaving to possible life threatening situations such as weather fronts (the need to divert) or warnings such as "possible hijackings" is simply left to chance??

That a message sent from ground control is simply thrown into the ether? That ground control receive no digital confirmation that the message has been received?

3. Read the ACARS PDF notes show at 09:21AM

pilotsfor911truth.org...

There was no "backlog" or "delay" in the printer or whatever. The message was physically sent at @09:21AM according to the notes. End of story.

I'm not sure whether it was you or gman who made the "backlog" claim. Do you agree now that this wasn't the case?

4. The message was apparently received and recognized by the cockpit MU in Pittsburgh 20 minutes after UA175 allegedly impacted. The timestamps "sent/received" claim is backed up by Ballinger, And Ballinger's "opinion" logically makes sense (re: point 2) and obviously holds more weight than anything you say.

Why did the ACARS message specify Pittsburgh if as you say it was just following the flightpath? Why specifically "stop" there over an hour after it had taken off?

Deep breaths now...

Bump.

That's for GL SnowCrash too, if he wants.

reply to post by snowcrash911

We already know the date/time at the bottom references telex printer times; which means we apparently don't have the actual acknowledgment information in the FOIA data.

Do we? Where was that cleared up?

Originally posted by gman1972
I think you guys are getting to the heart of it now.

The way I see it is in regular flights the ACARS sends it's position report every 10 minutes as stated, the ARINC system tracks this and continually routes the up links to the correct station.

The question is what does the ARINC system do when it stops receiving the position down link? I don't know, but would guess that being as how its a program that it would follow a normal routine, for example checking the stations farther along the planned route, or at least the direction of flight. Uplinks are lost, not frequently but sometimes, I would imagine that there would be a trouble shooting part built into this multimillion system which would attempt to reconnect with the airplane.

Sorry have to stop in mid thought, got something I need to deal with

From the Pilotsfor911Truth site:

Two types of flight tracking (or flight following) protocols are used for this process. Category A and B. First is Category A. This type of flight following uses Flight Tracking messages automatically sent from the aircraft, typically every 10 minutes. These messages are a data link and do not contain any text, therefore the customer airline does not receive these messages, they are used for Flight Tracking purposes only. When the Flight Tracking message is sent, the Central Processing System (CPS) recognizes which stations it has been sent through and picks the three best stations for routing messages to and from the aircraft. After roughly 10 minutes, another Flight Tracking message is sent from the aircraft, through a new set of ground stations in the vicinity of it's new location, and the Central Processing System dumps the old stations and replaces it with new stations better for routing messages to the aircraft. This process continues throughout the flight automatically. The second type of Flight Tracking, Category B, is a bit more simple. The aircraft continuously monitors all stations as it travels on it's course. The Central Processing System continuously chooses the best station for routing purposes while the aircraft is in flight. If the flight plan route is amended in flight, and a diversion is necessary, the Central Processing System chooses a new remote ground station along the diverted flight path based on this flight tracking protocol, tracking the aircraft

This is the part you must have missed..

The reason for this type of flight tracking, Category A and B, is due to the fact aircraft divert from their flight plans all the time, daily. Some have argued that MDT and PIT were chosen for ground station routing due to the original planned route of flight, BOS to LAX. However, if ACARS routing was based on original flight planned route, aircraft diverting from their original route of flight would not be able to communicate via ACARS as they would quickly leave the areas in which remote ground stations have been chosen, rendering the network useless for the airline, and most importantly, the aircraft. On 9/11 especially, many aircraft were diverted from their original flight plans. If the ACARS network was solely based on flight planned route, 100's if not thousands of aircraft, would not have been able to communicate with their company and/or ATC via ACARS. Chaos would have ensued as ACARS communication is a valuable asset to facilitate aircraft operations and flight safety, and the skies would never have been cleared as quickly as reported.

and

The reason Dispatchers have an ASD is due to the fact the aircraft across the globe deviate from their cleared flight plans daily due to weather, traffic, etc. With an ASD, Dispatchers can keep track of their flights and alert for weather (or other adverse conditions) along the route. Even if Dispatchers had the capability to choose which specific ground station to route a message, why would they choose MDT and then later PIT if the aircraft is diverting back to the east on their monitors? The answer is, they wouldn't. The hypothesis that Remote Ground Station routing is based on original flight plan is completely absurd and usually attempted by only those who obviously are not interested in the facts, instead need to speculate to hold onto their beliefs. As described, the Central Processing System routes messages through remote ground stations based on Flight Tracking Protocol(5).

Source

Hi there, I still haven't figured out how to copy posts in different parts so i'll put my replies under your typing, hope that's okay.

Originally posted by ThePostExaminer

Originally posted by gman1972

Originally posted by ThePostExaminer

Ballinger worked through the ACARS messages for the FBI as seen in the ACARS PDF. Are you really trying to tell us that this guy's "opinion" isn't worth taking into consideration over yours (whatever it is now) and gman's??

I don't have an opinion examiner, I am sharing my knowledge on the subject and my access to be able to share it. I invited people to teach me something that I may not know. Not sure why you guys keep dragging me though the mud, I haven't said one bad, condescending, aggressive, or otherwise remark this whole time.

Geese even when i was misquoted I didn't come out with, "obviously you can't read" or "Please reread what I wrote you obviously didn't pay attention." or any of the other common remarks.

Can you guys just calm down a bit so we can have a rational discussion on this?

Gman, I think that was the first post that I've addressed directly to you. I don't see how you find it "aggressive" or how I'm dragging you "through the mud". As I said in the post, I wasn't sure whether you or Proudbird made the "backlog" remark. It was you wasn't it?

I was also looking at the P4T site when I made that comment, not really being dragged through the mud on this thread, but on the other site I was getting only selective quotes of what I wrote being posted and made fun of ect. Sorry i should have been more clear that it was a combination of the two. And no it wasn't me that made the backlog remark, I think it was proudbird... I dont' even know how to link to an external website yet lol.


You've stated that the timestamp at the bottom of the printout "definitely" isn't "time received". That's about as finite as it gets, no?

Well yes, that is what I said and then I provided proof of that by sending an acars to an aircraft which didn't exist. How could I get a "time received" stamp at the bottom if there was nothing to receive it?

I agree (and always hope) that these issues can be discussed rationally That's why I want to narrow the parameters of the argument instead of everybody putting their doots up!

I agree, the thread seem to have become much more productive and constructive in the last day.

1. As for the second timestamp being the "printer", what logical purpose does it serve to know what time it was printed??

Beats me, I guess that's the way it was set up to begin with. I did quote a maual from the people that designed the system saying that that is what that is, why they did it that way I don't know.

2. When you said that the printer takes "one or two minutes"...I've read on a ARINC newssheet from 2000 that the messages can range from 15-30 seconds to 1-2 minutes to reach the aircraft. This matches the majority of ACARS messages linked to in the PDF, doesn't it? And why would a printer take 1-2 minutes within a self contained office?

No, originally I said that they come through pretty fast like 15-30 seconds, then I was challanged if it's always that way or if it could take a few minutes. I said somtimes it can take like 1 or 2 minutes but usually it's done within 30 seconds or so... I'm posting from memory, so forgive me if I'm not requoting myself perfectly.

There's also this quote from a dispatcher at airline.net from 2007

And ACARS messages are fast. Out of my office window I can see aircraft departing from 19R at ARN. When the aircraft lifts off ACARS sends the off message. VHF to the local ACARS transceiver at ARN, then landline to our base at LHR, then back to my printer as a MVT message. I hear the printer clack out a MVT msg and look up and see the A319 at 100ft on departure. It is also useful when they arrive. I don't have to meet aircraft, just be ther a few minutes later. So I can relax in the office and wait till the arrival ACARS msg arrives on the printer. They all make exactly the same sound so I can tell it is a MVT msg from across the room. Then I put my coat on and get in the van.

I know it's an automated response from the aircraft to ground control, but the guy is obviously saying that there is an interaction between a message sent and the printer. Acknowledgement.

3. Again I ask you (apologies if you've answered this already) to read through the points I raised, especially regarding the logic of ground control sending a message that may entail a request for immediate diversion, for example, and the apparent claim being made here that ground control doesn't know whether the message has been received or not. That's what your basically saying, right?

Cheers

Out of characters will continue in another post

Originally posted by ThePostExaminer

And ACARS messages are fast. Out of my office window I can see aircraft departing from 19R at ARN. When the aircraft lifts off ACARS sends the off message. VHF to the local ACARS transceiver at ARN, then landline to our base at LHR, then back to my printer as a MVT message. I hear the printer clack out a MVT msg and look up and see the A319 at 100ft on departure. It is also useful when they arrive. I don't have to meet aircraft, just be ther a few minutes later. So I can relax in the office and wait till the arrival ACARS msg arrives on the printer. They all make exactly the same sound so I can tell it is a MVT msg from across the room. Then I put my coat on and get in the van.

Yup, that's a sound I know all too well as that means work done lol! FYI some planes sent those automatic messages at different times, some are when gear is selected up, some is when t/o power is applied, some is when the wheels leave the ground.

I know it's an automated response from the aircraft to ground control, but the guy is obviously saying that there is an interaction between a message sent and the printer. Acknowledgement.

I don't think so, not in an acknowledgement way anyway. It's like if you send an email, you have no idea if the other party received it. Sometimes the off blocks message doesn't get through to the printer for some reason, so I message scan the aircraft and find out what it was. There is no message that gets sent to the a/c saying message not transmitted or anything.

3. Again I ask you (apologies if you've answered this already) to read through the points I raised, especially regarding the logic of ground control sending a message that may entail a request for immediate diversion, for example, and the apparent claim being made here that ground control doesn't know whether the message has been received or not. That's what your basically saying, right?

Cheers

No, actaully that's a point that I wanted to bring up again. You can check if a message was received or not by scanning the acars up/down link page, if it didn't get received it would show as NOACK, instead of up. I did state this way back earlier. However on the copy that comes out of the printer it will not show this in any way, it will still show the time it was printed out, even if it wasn't received. I cannot get an example of this because there is no way for me to make a message be noack, just happens sometimes. I'll just have to ask you to take my word for it that even though it gets rejected and I can see it was rejected I will still have a copy of the ACARS message on my desk with the time stamps as usual.

Hope that clears it up.
Have a good one

Further to my above last point, it is also common in my airline that when you send a message of any kind of importance that you ask the pilots to confirm receipt of the message. Or pls ACK my previous, for example

reply to post by gman1972


This is exactly right, I'd forgotten about that!! Glad you mentioned it, it's so common and automatic (for us) that the act of acknowledging that we do isn't even thought about, we just do it.

....it is also common in my airline that when you send a message of any kind of importance that you ask the pilots to confirm receipt of the message. Or pls ACK my previous, for example.

^ ^ ^ ^ ^ This, closes the case on the ridiculous claims by "Woody Box" and "PfT" (or, "P4T").

When a "Free Text" message comes in, it has a button that is highlighted (I think it's 6R, the bottom right button, IIRC). The screen shows the abbreviation 'ACK' and ' > ' arrow prompt point to the button on then side of the screen, on the CDU.

*[ ACK> ]*

See how "DIRECTORY>" is shown on the screen in the image below:



It looks similar, just different key prompt message on the screen.

THAT is when the acknowledgement message is sent! NOT just merely because the airplane receives the ACARS message in the first place!!

I knew there was something not right in these claims, but wracked my brain to prove it. It is sometimes the simplest explanations that escape us!

reply to post by ThePostExaminer


Yes I read all that before but thanks for reminding me that I lost my train of thought on it last night.

It just doesn't make sense to me though.What I am getting at is, as I said during normal ops the position reports to ARINC tell the system where the a/c is and then it can sent the messages to the right station to transmit to the a/c. If the plane has to divert, or reroute then this would still keep updating and the messages would always be sent to the correct station to transmit to the a/c because the position reports keep updating where the plane is. Even if it was going hundreds of miles out of the way, the position reports would keep telling ARINC where to route the messages to.

The question is what happens if those position reports stop coming in, as in the plane crashed or something? Probably nothing until someone tries to uplink to it, then when they do the ARINC system probably tries to "find" the plane that it had lost contact with to transmit the message, I figure they probably have it programed to follow logical steps to try and reaquire the target so to speak. This is just an idea on my part and I have nothing to back it up, but maybe that would be why the uplink was sent to a station further along the ffiled ICAO flight plan, it was trying to find the aircraft so it could transmit the message to it.

But again I don't have anything to back this up, just thinking out loud. I would think that the people who designed the system would have built in something, so that if the system looses an airplane that it would take steps to try and locate it and send the message instead of doing nothing. Sometimes ACARS goes down, some times it's u/s, rarely but it has happened. There must be a back up way ARINC uses to try and uplink messages to planes that aren't sending position info to them. I find it hard to believe that if a flight diverts more that 200nm from it's route that ACARS would then be useless.

Again take my comments with a grain of salt.

reply to post by ProudBird


If I have a friendly pilot today, I'll ask if they hit that ACK button after they receive a message every time. So maybe the NOACK message is just because they didn't hit the button, I didn't know that lol. I'll report back in the afternoon if I get a chance to ask.

How sturdy is the system? What are the chances it could have been able to communicate after impact? How is it supplied with power?

This PDF might be of interest,
AIR GROUND DATA LINK VHF AIRLINE COMMUNICATIONS AND REPORTING SYSTEM
(ACARS) PRELIMINARY TEST REPORT
Albert Rehmann
February 1995
DOT/FAA/

2.2.1 Time Stamp. Every message, sent or received by the ground equipment has its own valid time stamp. Time stamps generated by the ground equipment were compared to the MU generated time stamps in the analysis of transit delay.

ntl.bts.gov...

On the aircraft, the ACARS system was made up of an avionics computer called an ACARS Management Unit (MU) and a CDU (Control Display Unit).

www.aviationarticles.net...