For those interested in the various aircraft systems for PA (public address) and aircraft status system for aircrew, I found this interesting training doc PDF online [1] for the A320/321.
I have been looking at section "03-010 CABIN INTERCOMMUNICATION DATA SYSTEM"
It does not mention the "medical intercom jacks" in overhead bins that are mentioned at the end of the article
Another idea is that there is a source file that is copied onto the flash card on a regular basis and someone has hacked the source back at the office or something. Seems more likely because that wouldn't require the perpetrator to be on each flight and thus less likely to get caught. Some of these flights play music as you board the plane, could it be that this comes from music on a flash card and someone has replaced that?
They would probably notice that but it does seem like some former passenger most likely installed something that's patched into the system. It may just be a recording from a flash drive. Or it could also be more sophisticated and patch into the wifi as well. You could also imagine it having a microphone for added hijinx but none of the interactions seem to suggest that.
If there is such a flash card, this sounds like the easiest explanation. Someone swapped the card with a file that starts with the real announcement, then X minutes of silence, followed by joke sounds.
Looked at that too, but since unless I am missing something, that appears to be in the captain’s cabin based on linked document from the parent of this comment thread; which means it would not only be hard to access, but once placed, very likely be hard to recover and would have been checked too, likely even in flight while the audio continued to be heard.
If those are 1/4" or 6.35mm audio phone jacks, I'm sure there are lots of electrical engineers who could design a pre-recorded player that would fit
ENTIRELY inside the jack without protruding outside the jack whatsoever.
I'm struggling to understand how this would explain the account here:
>Then the master power button up at 1L for the cabin power kept getting I pushed so it would shut off all the IFE, seat power and outlets. I had to push the button on again about 3 times inflight. Then the 2 got a call with the same groaning noise and thought it was one of us playing a joke but it wasn't us.
>It certainly was freaking all of us and the passengers. They wanted off the plane as bad as we did. The 2 be FAs said they had been on the plane the other day and the same thing happened. I had a visual on each FA when the noise would come over the PA and one time when the FO was doing a break so unless the captain was playing a long sick, joke I don't have an explanation.
While it is plausible that the hack compromises the entire comm system, it's unlikely. My bet is that the steward made an incorrect association between the sounds and normal system behavior. These inaccurate retellings are extremely common in ghost stories.
Only time will tell, but I'm almost certain I'm right on this one.
My best guess its an unfunny "Easter Egg" that triggers after something like 5,000 hours of uptime. I think I remember some bug in Boeing or some other system that they need to actually be rebooted every 100 days.
I'm one of those people who thinks easter eggs are great, and miss the days when you had a decent chance of coming across one in a program or game.
The FAA does not agree with that. The FAA probably thinks that easter eggs in avionics software are a crime. And I agree with that position! Aviation, medical, military, and any other critical software should not contain easter eggs, and it should be an offense to knowingly include one. Stuff like this (even though it's probably not an easter egg) is a great example why. Just imagine the cost to patch this if it's widespread... and it has to be patched, because this one can literally kill people if you don't fix it (think spooked flight crews making rushed or generally poor decisions if you don't think this is potentially lethal).
These sounds are familiar to me from using “ pink trombone”, or praat, both vocal synthesizer. I would guess that a text - to - speech system is bugging out.
https://dood.al/pinktrombone/
The sounds probably aren't a prank or a recording of a human at all. I am guessing it is just a resonant frequency of a standard part being picked up as a feedback loop due to some component which was recently exposed after a change in maintenance protocols. (or something similarly mundane) I have heard all sorts of ghoulish sounds picked up while tinkering with RF and old microchips. Our brains tend to anthropomorphize such sounds when we have never experienced them before. Going straight to the wildest explanations like "hacking" or "ghosts" is fun for our brains but further reinforces the inaccurate picture we had painted for ourselves initially.
I listened to the recording in the article, and it sounds like a human. Further, it sounds like the same human. And I found myself reading the emotional message behind the sounds. So...yeah, it's an interesting theory, but I think it's more likely a prank or someone making a point.
There's a point in the MP3 that sounds possibly non-human at 0:18 to 0:19. The pitch goes quite high in a way that sounds artificial.
But overall I agree that it sounds very human. For example, the grunt at 0:13 doesn't sound like random noise at all, it could easily be a sound effect in a movie or game.
Another way to think about it: there are a lot of planes and different ways the PA system could go wrong. You’re much less likely to read an article about a plane being ‘haunted’ by a strange clicking or buzzing or humming or white noise sound.
There was a post on Reddit, I think, that explained that there were ports in the luggage bins every so many seats that were for for medical comms to run on. Someone plugging something into this port could play whatever they wanted from a computer. It's probably the same person doing the same joke over and over.
The only problem for them is that AA could cross reference the travelers on those flights to figure out who it was, if it was a passenger using these ports to prank.
>Two indicator lights (red/green) serve as attention getters and ensure a far reaching call function when a respective message is displayed. The red light is used for system and emergency information, the green light for communication information. The lights are steady in normal situations and will flash in emergency situations.
>The ACPs give a long-range visual indication about the system status (e.g. PAX call active). They are installed at the ceiling in the middle of the aisle between the passenger/crew doors, close to
the attendant stations.
>The lighted segments are activated either continuously (steady) or flashing.
In case of "normal" calls they are not flashing (steady), in case of "abnormal" or "emergency" situations they will flash. Only the blue PAX call field will never flash, this will be always a "normal" indication
These indicator lights would be helpful in narrowing down if the emergency system was being engaged or not. Could potentially point to exploitation/hack of the PA system rather than rogue utilization of normal functions.
It could also be a maintenance person who has access to other parts of the plane. Did all the flights go through the same airport at any point? Or what if it’s something a flight attendant did? If so, it could even be flights through different airports.
This might narrow it down some, but I have been on weekend flights that I recognized people on the return leg from the away leg. But even going from 200+ people to 10 would help
Pretty interesting. If it’s a hoax, it’s a pretty good one.
If it’s a hack of any sort someone is taking their life in their hands because being caught tampering with any commercial airline systems could mean significantly jail time. Cleaning crews and other staff have enough time on the plane to do something… I’m thinking like an Adafruit Waveshield with a timer or something.
If it’s a ghost, it seems like a horny adolescent one.
"Whoever ... causes to be made unworkable or unusable ... any part ... used in connection with the operation of such aircraft, if such placing ... is likely to endanger the safety of any such aircraft"
The "part" is the PA system. While the device is playing the prank sound, it is temporarily "made unworkable" for its intended purpose of allowing the crew to communicate with the passangers. This "endangers the safety of the aircraft" because in certain situations it's possible the crew would need to communicate quickly with passangers or have silence so that they can understand each other and focus on solving an issue.
Edit: Looks like captain could override, flight attendants couldn't. That still causes a safety risk because in an emergency the cockpit might want to focus on flying the plane while the flight attendants instructed the passangers. Plus the distraction factor remains.
49 U.S. Code § 46504 - Interference with flight crew members and attendants
An individual on an aircraft in the special aircraft jurisdiction of the United States who, by assaulting or intimidating a flight crew member or flight attendant of the aircraft, interferes with the performance of the duties of the member or attendant or lessens the ability of the member or attendant to perform those duties, or attempts or conspires to do such an act, shall be fined under title 18, imprisoned for not more than 20 years, or both. However, if a dangerous weapon is used in assaulting or intimidating the member or attendant, the individual shall be imprisoned for any term of years or for life.
* Unless someone had made dongle that once inserted looked like the same plugs, but raised enough to hide the dongle and match the color/texture of the surrounding plastic. The fake plugs on the outside would not even need to be functional and the device could be set to start on a delay, so whoever is placing them is not physically on the flight when it starts. It could even have an accelerometer to turn on after take-off and turn off on landing. If the person intentionally booked a seat at end of the plane, very likely they could easily add it when everyone is trying to leave the plane.
Credit card skimmers do something similar all the time:
This must be the explanation. The one thing I can't quite understand though is how someone could be simultaneously so very technically clever and yet execute such a mundane level of prank. This could be so much more epic if someone got more creative with the choice of audio track. I mean, it could be anywhere from totally hilarious to actual terrorism. Scary to think of the possibilities.
If this is truly the explanation though, I wonder if the public will ever get to hear confirmation or if they'll just remove it and refuse to talk about it / threaten employees to keep it quiet.
I wouldn't be surprised at all if this was the case - kind of like an internet flash mob all in on the joke, waiting for reputable news sources to pick it up and show their lack of journalistic integrity.
I mean, the only thing I could see them doing is asking the flight attendants or AA, but both of those are likely hard to get an actual answers for (AA would most likely say 'we are investigating' and would never follow-up). If something is on social media and there are enough corroborating accounts, it's probably enough to write a news article about.
> my go-to assumption when the source originates from Tiktok is to assume it's fake or staged.
Wise, although wiser to make that assumption for most sources. Until this starts being reported independently by more reliable sources then I assume it’s fake.
In this article the author claims to have talked to American Airlines about it:
>American Airlines inspected the Boeing 737-800 as well as the P.A. system itself after these reports. They tell me that maintenance “determined the sounds were caused by an issue with the PA amplifier. There was no external access to the system.”
> “determined the sounds were caused by an issue with the PA amplifier. There was no external access to the system.”
Hard to agree. Those sounds are almost certainly a human voice, presumably digitized. Unless the issue with the PA amp is that someone connected a sample player to it.
Where did it say the source was from tiktok? They cited several separate Tweets about this same issue across multiple flights. They have recordings too
Readit News
It does not mention the "medical intercom jacks" in overhead bins that are mentioned at the end of the article
[1]:https://caisatech.net/uploads/XXI_3_AIRBUS_H51_A320_O_CCOM_R...
I wonder if someone replaced the standard announcement with a 5 hour long file with intermittent burps and groans....
https://aviation.stackexchange.com/questions/12776/how-are-t...
Jacking into that would not be inconspicuous.
Deleted Comment
>Then the master power button up at 1L for the cabin power kept getting I pushed so it would shut off all the IFE, seat power and outlets. I had to push the button on again about 3 times inflight. Then the 2 got a call with the same groaning noise and thought it was one of us playing a joke but it wasn't us.
>It certainly was freaking all of us and the passengers. They wanted off the plane as bad as we did. The 2 be FAs said they had been on the plane the other day and the same thing happened. I had a visual on each FA when the noise would come over the PA and one time when the FO was doing a break so unless the captain was playing a long sick, joke I don't have an explanation.
https://twitter.com/xJonNYC/status/1572358118985633795
Any ideas?
I can't even get passed the first sentence of this. What does any of this mean?
Only time will tell, but I'm almost certain I'm right on this one.
https://youtu.be/0l2jUPI1fpk
The FAA does not agree with that. The FAA probably thinks that easter eggs in avionics software are a crime. And I agree with that position! Aviation, medical, military, and any other critical software should not contain easter eggs, and it should be an offense to knowingly include one. Stuff like this (even though it's probably not an easter egg) is a great example why. Just imagine the cost to patch this if it's widespread... and it has to be patched, because this one can literally kill people if you don't fix it (think spooked flight crews making rushed or generally poor decisions if you don't think this is potentially lethal).
Deleted Comment
But overall I agree that it sounds very human. For example, the grunt at 0:13 doesn't sound like random noise at all, it could easily be a sound effect in a movie or game.
Dead Comment
The only problem for them is that AA could cross reference the travelers on those flights to figure out who it was, if it was a passenger using these ports to prank.
Deleted Comment
>The ACPs give a long-range visual indication about the system status (e.g. PAX call active). They are installed at the ceiling in the middle of the aisle between the passenger/crew doors, close to the attendant stations.
>The lighted segments are activated either continuously (steady) or flashing. In case of "normal" calls they are not flashing (steady), in case of "abnormal" or "emergency" situations they will flash. Only the blue PAX call field will never flash, this will be always a "normal" indication
These indicator lights would be helpful in narrowing down if the emergency system was being engaged or not. Could potentially point to exploitation/hack of the PA system rather than rogue utilization of normal functions.
https://twitter.com/Lekonish/status/1455696144571326466
Deleted Comment
If it’s a hack of any sort someone is taking their life in their hands because being caught tampering with any commercial airline systems could mean significantly jail time. Cleaning crews and other staff have enough time on the plane to do something… I’m thinking like an Adafruit Waveshield with a timer or something.
If it’s a ghost, it seems like a horny adolescent one.
not sure. A cursory reading of https://www.law.cornell.edu/uscode/text/18/32 doesn't mesh with a silly prank. Which law do you think they are breaking?
The "part" is the PA system. While the device is playing the prank sound, it is temporarily "made unworkable" for its intended purpose of allowing the crew to communicate with the passangers. This "endangers the safety of the aircraft" because in certain situations it's possible the crew would need to communicate quickly with passangers or have silence so that they can understand each other and focus on solving an issue.
Edit: Looks like captain could override, flight attendants couldn't. That still causes a safety risk because in an emergency the cockpit might want to focus on flying the plane while the flight attendants instructed the passangers. Plus the distraction factor remains.
49 U.S. Code § 46504 - Interference with flight crew members and attendants
An individual on an aircraft in the special aircraft jurisdiction of the United States who, by assaulting or intimidating a flight crew member or flight attendant of the aircraft, interferes with the performance of the duties of the member or attendant or lessens the ability of the member or attendant to perform those duties, or attempts or conspires to do such an act, shall be fined under title 18, imprisoned for not more than 20 years, or both. However, if a dangerous weapon is used in assaulting or intimidating the member or attendant, the individual shall be imprisoned for any term of years or for life.
- law that says you aren’t allowed to vandalise other peoples stuff (for the verdict); and
- the thing being vandalised is the thing used to coordinate safe evacuation of passengers on a vessel (for a hefty sentence).
Like scribbling on a painting vs a bus stop — let the justice be done in the sentencing.
https://i.stack.imgur.com/5w241.jpg
* Unless someone had made dongle that once inserted looked like the same plugs, but raised enough to hide the dongle and match the color/texture of the surrounding plastic. The fake plugs on the outside would not even need to be functional and the device could be set to start on a delay, so whoever is placing them is not physically on the flight when it starts. It could even have an accelerometer to turn on after take-off and turn off on landing. If the person intentionally booked a seat at end of the plane, very likely they could easily add it when everyone is trying to leave the plane.
Credit card skimmers do something similar all the time:
https://www.google.com/search?q=how+to+spot+credit+card+skim...
____________
This guess is based on information provided by two prior HN comments:
[1] PDF of flight systems:
- https://news.ycombinator.com/item?id=32958432
[2] Photo of medical audio jacks:
- https://news.ycombinator.com/item?id=32959686
I mean, the only thing I could see them doing is asking the flight attendants or AA, but both of those are likely hard to get an actual answers for (AA would most likely say 'we are investigating' and would never follow-up). If something is on social media and there are enough corroborating accounts, it's probably enough to write a news article about.
Wise, although wiser to make that assumption for most sources. Until this starts being reported independently by more reliable sources then I assume it’s fake.
>American Airlines inspected the Boeing 737-800 as well as the P.A. system itself after these reports. They tell me that maintenance “determined the sounds were caused by an issue with the PA amplifier. There was no external access to the system.”
https://viewfromthewing.com/no-theres-no-ghost-in-the-machin...
Hard to agree. Those sounds are almost certainly a human voice, presumably digitized. Unless the issue with the PA amp is that someone connected a sample player to it.
Former pro audio engineer here.
Dead Comment