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A mysterious voice is haunting American Airlines’ in-flight announcements

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Re: A mysterious voice is haunting American Airlines’ in-flight announcements

#251

Post by joezydeco »

oefrha wrote: post #181
panarky wrote: post #168

Earlier quoted context omitted.

I've flown American six times in the last ten days, and four of the flights had chaos with the entertainment system. No groans or heavy breathing on the PA, but flight attendants had to "reboot the system" once or twice every flight.

I once captured the Linux boot screen of a United Boeing 737 infotainment system. Apparently I still got that photo. OCRed text for lols: video capture buffer0 40b37460 video capture buffer1 40a8dd60 wideo_capture buffer2 409e4610 geode_: gamma black+csccorrection VAL2: Registered "NSC Geode V4LZ UBI driver" as char device B1, 224 VAL2: Registered "NSC Geode V4L2 Capture driver" as char device 81, geode_v: Unknown st…

Oh man, the NatSemi Geode (aka Cyrix MediaGX). What a system. I'm amazed anyone got a usable Linux system out of it at all.

Re: A mysterious voice is haunting American Airlines’ in-flight announcements

#252

Post by [deleted] »

stickfigure wrote: post #165
rx_tx wrote: post #6

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 [1]: https://caisatech.net/uploads/XXI_3_AIR…

A bit of searching for airplane medical communications jacks turned up this picture: https://aviation.stackexchange.com/questions/12776/how-are-t... Jacking into that would not be inconspicuous.

[deleted]

Re: A mysterious voice is haunting American Airlines’ in-flight announcements

#253

Post by FartyMcFarter »

balex wrote: post #246
duckqlz wrote: post #235

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 anthropomorph…

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.

Re: A mysterious voice is haunting American Airlines’ in-flight announcements

#254

Post by zoomablemind »

It may be a wrong and long-stretch of an idea, but what if this is an audio being played into that headphones jack at a seat?

Directly, this should not be possible (input vs output on the amp), but in case the PA mic signal is routed to common amp after keying and preamp, this technically may be possible.

Now, if the "keying" includes some specific signal to allow the routing to PA, the question is if the "keying" signal can be sent from the seat's console. Then just play back the annoying track into the headphones jack.

Re: A mysterious voice is haunting American Airlines’ in-flight announcements

#255

Post by atkailash »

balex wrote: post #246
duckqlz wrote: post #235

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 anthropomorph…

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.

No post body was provided.

Re: A mysterious voice is haunting American Airlines’ in-flight announcements

#257

Post by O__________O »

In cabin medical audio jacks [2] are the likely explanation, but it would be easy to inspect those:

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

Re: A mysterious voice is haunting American Airlines’ in-flight announcements

#258

Post by O__________O »

zoomablemind wrote: post #254

It may be a wrong and long-stretch of an idea, but what if this is an audio being played into that headphones jack at a seat? Directly, this should not be possible (input vs output on the amp), but in case the PA mic signal is routed to common amp after keying and preamp, this technically may be possible. Now, if the "keying" includes some specific signal to allow the routing to PA, the question is if the "keying" si…

Linked article appears to state the PA system is physically isolated — which I would assume means only known components of the PA system interact with each other:

>> Professional reverse engineer/hardware hacker/security analyst Andrew Tierney (aka Cybergibbons) dug up the Airbus 321 documents in this thread, and is stumped too.

https://twitter.com/cybergibbons/status/1573328954517499904

Re: A mysterious voice is haunting American Airlines’ in-flight announcements

#259

Post by zoomablemind »

O__________O wrote: post #258
zoomablemind wrote: post #254

It may be a wrong and long-stretch of an idea, but what if this is an audio being played into that headphones jack at a seat? Directly, this should not be possible (input vs output on the amp), but in case the PA mic signal is routed to common amp after keying and preamp, this technically may be possible. Now, if the "keying" includes some specific signal to allow the routing to PA, the question is if the "keying" si…

Linked article appears to state the PA system is physically isolated — which I would assume means only known components of the PA system interact with each other: >> Professional reverse engineer/hardware hacker/security analyst Andrew Tierney (aka Cybergibbons) dug up the Airbus 321 documents in this thread, and is stumped too. https://twitter.com/cybergibbons/status/1573328954517499904

I vaguely remember that PA messages are heard in headphones, so the PA signal is being patched through at some point.

It's not clear how the "seats" bus is isolated. I assume it's a bus, so that seats are addressable. The seats should at least be able to send the "need attendant" signal.

I hope a qualified technical analysis already pointed a few possible vectors for this. The question is in remediation and, well, identification of the perp(s).

Either way, at this moment the story seems to act more as an attracting magnet than repelling for the airline. Back during summer, it certainly was another level of annoying and disturbing.

Re: A mysterious voice is haunting American Airlines’ in-flight announcements

#260

Post by bagels »

6stringmerc wrote: post #216
bagels wrote: post #209

Earlier quoted context omitted.

I have a similar kind of fun story. The emergency phone on the elevator at work had a phone number somewhat close to that of an appliance store. People would call the number, the elevator phone would immediately put them on speaker phone. I figured this out one time I heard a faint phone breathing sound, and I started speaking with the caller. This happened again about once a year, and I had a fun time explaining to…

Okay thank you for sharing - I answered a spam call on an elevator emergency phone once and I was puzzled but found it funny. So there’s an actual number…oh boy if only there was a registry…

Yeah, unfortunately I couldn't get the elevator number from the callers. I really wanted it to play pranks on coworkers.
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