4 ms·

This is wild to listen to. A) this is a busy atc channel and it's amazing how much complexity is coordinated over noisy radio. B) within minutes of the accident

by fblp 2y ago

This is wild to listen to. A) this is a busy atc channel and it's amazing how much complexity is coordinated over noisy radio. B) within minutes of the accident happening (at 11:48) the ATC controller is calmly asking helicopters in the air if they can assist in search rescue operations asking, if they have search lights and direction them. This is whilst diverting and grounding flights.

consp 2y ago
> over noisy radio I've been told the noise on the recordings is always a lot worse than in practice due to the location of the recording antenna not being ideal. I have no idea if this is correct or not. Maybe someone can enlighten this.
- thowawatp302 2y ago
  Yes, having tried to listen to ATC with an SDR— the public recordings are made from antenna that placed near the airport, while the official recordings are made from the feeds that the ATC is listening to— and those antenna have their lobes pointed toward the sky.
- FL410 2y ago
  Yep. Radios are much clearer in the air. VHF is mostly line of sight and planes have the benefit of altitude. Approach/center comms can get a bit scratchy at times mostly due to distance, but approach/tower is almost always perfectly clear.
- jillesvangurp 2y ago
  I watch a lot of pilots on Youtube. Most of them use some kind of audio splitter to record sound. You hear what the pilot hears. But minus the plane noise, vibrations, etc (unless that's mixed in via some open microphone). So, it's actually better. So, it really is that bad. Especially when flying low, on the edge of the range of the radios, etc. VHF radio is ancient technology. It's not great even under ideal conditions. If your phone calls sounded that bad, you'd want to upgrade your phone or switch operator. Really not acceptable for consumer grade communication. Not even close. This is how phones sounded half a century ago. "can you hear me .... are you there ..... can you talk louder ....". My grand mother never really unlearned 1930s phone etiquette. Phone calls with her were short (cause expensive) and she'd be shouting at you because that's what you did. Be brief, loud, hang up as soon as possible. That's what pilots still do. My grand mother was born during WW I (not II) and she's been dead for nearly 20 years. The aviation world is very conservative with new/better/any technology. They stick with "what works". Even if arguably it barely works. Like pretty much the vast majority of radio exchanges between pilots and controllers over VHF radio. Learning how to talk on the radio is the second hardest part of getting an instrument rating. The only thing that's harder is flying a plane with zero visibility ... while suffering extreme information overload because of the constant radio chatter and dealing with confused/stressed/pissed off controllers who have to juggle you and 20 other planes. A lot of radio exchanges are routine exchanges that involve very basic information: call signs, transponder codes, codes for approaches/departures, courses, altimeter settings, altitudes, weather information, etc. And then a lot of double checking the other side heard correctly, repeating back what you heard, etc. Radio communication compensates for the lack of a more robust/sane way of exchanging information. There literally is no way for a controller to send you information in written format. Other than using their private phones. So, it all gets spelled out over low quality VHF radio. There's no good technical reason to not do something vastly more reliable, less intrusive, and less error prone. Some might say safer. Many planes have star link connections these days. The passengers get better connectivity than the pilot. They could be having video calls with the controller with crystal clear audio from anywhere on this planet instead of yelling to them over VHF only when they are in range. They could be sending each other emails, documents, digital maps, and lots of other machine readable information, etc. Not a thing. It's more a challenge of agreeing on what such a vastly better thing would be and then updating each and every plane and tower, airport, controller world wide with equipment that supports that. Add design by committee to the mix and the "state of the art" is something that would make any competent engineer born after 1970 blush.
  - throw0101c 2y ago
    > A lot of radio exchanges are routine exchanges that involve very basic information: call signs, transponder codes, codes for approaches/departures, courses, altimeter settings, altitudes, weather information, etc. They are also in a fairly standardized format with reserved "keywords" for many important aspects of operation ("hold short", "line up and wait", "cleared to X"): * https://skybrary.aero/sites/default/files/bookshelf/115.pdf https://skybrary.aero/sites/default/files/bookshelf/115.pdf English is the lingua franca of ATC, but it is recognized it is obviously not everyone's first language.
  - jcrawfordor 2y ago
    Honestly a lot of those recordings probably do sound a lot worse than the radio audio. I rarely see YouTube recordings that are as audible as the radio is in person. Here's what seems to be the reason: The common splitters you can buy to break out your headset connector to a recorder don't account for the signal level, which is very high on the headset connectors as aviation headsets are traditionally pretty high impedance. I've struggled with the headset audio blowing out even a fairly nice recorder (a Zoom) with the gain turned all the way down. Phones and pocket reporters don't even offer a gain adjustment and the recording can end up almost unusable. In a lot of YouTube videos of pilots, even most, it's pretty obvious that it's clipping at the recorder the whole time. Perhaps even worse, a lot of people are using like a GoPro with auto-gain, so you get the worst of both worlds: it ramps up gain until the noise is loud, and then when someone starts talking, it ramps down the gain, but a little too slowly, and it's still clipping even when it hits minimum. It's not very common to have trouble understanding the controller when in the air. AM radio at line of sight (as is the case when you're flying) is pretty robust. Maybe the hardest thing to understand are helicopter pilots because there's often rotor noise on their end.
  - FL410 2y ago
    YouTube is not a good representation of what you hear in a headset. Half the time the mic taps aren't impedence matched and sound like shit. Besides that, most "controlling" (i.e. instructions that require action) comms have a handshake of sorts - the pilot repeats back the instruction for the controller to confirm. They don't just bark out instructions and hope you heard it, they listen for you to read them back, and will keep doing so until successful. So, even in cases when the comms are degraded, you will go back and forth until there has been positive confirmation (readback) you heard the instruction correctly (or they'll just give you a new frequency).

by fblp 2y ago

consp 2y ago

> over noisy radio I've been told the noise on the recordings is always a lot worse than in practice due to the location of the recording antenna not being ideal. I have no idea if this is correct or not. Maybe someone can enlighten this.

thowawatp302 2y ago
Yes, having tried to listen to ATC with an SDR— the public recordings are made from antenna that placed near the airport, while the official recordings are made from the feeds that the ATC is listening to— and those antenna have their lobes pointed toward the sky.
FL410 2y ago
Yep. Radios are much clearer in the air. VHF is mostly line of sight and planes have the benefit of altitude. Approach/center comms can get a bit scratchy at times mostly due to distance, but approach/tower is almost always perfectly clear.
jillesvangurp 2y ago
I watch a lot of pilots on Youtube. Most of them use some kind of audio splitter to record sound. You hear what the pilot hears. But minus the plane noise, vibrations, etc (unless that's mixed in via some open microphone). So, it's actually better. So, it really is that bad. Especially when flying low, on the edge of the range of the radios, etc. VHF radio is ancient technology. It's not great even under ideal conditions. If your phone calls sounded that bad, you'd want to upgrade your phone or switch operator. Really not acceptable for consumer grade communication. Not even close. This is how phones sounded half a century ago. "can you hear me .... are you there ..... can you talk louder ....". My grand mother never really unlearned 1930s phone etiquette. Phone calls with her were short (cause expensive) and she'd be shouting at you because that's what you did. Be brief, loud, hang up as soon as possible. That's what pilots still do. My grand mother was born during WW I (not II) and she's been dead for nearly 20 years. The aviation world is very conservative with new/better/any technology. They stick with "what works". Even if arguably it barely works. Like pretty much the vast majority of radio exchanges between pilots and controllers over VHF radio. Learning how to talk on the radio is the second hardest part of getting an instrument rating. The only thing that's harder is flying a plane with zero visibility ... while suffering extreme information overload because of the constant radio chatter and dealing with confused/stressed/pissed off controllers who have to juggle you and 20 other planes. A lot of radio exchanges are routine exchanges that involve very basic information: call signs, transponder codes, codes for approaches/departures, courses, altimeter settings, altitudes, weather information, etc. And then a lot of double checking the other side heard correctly, repeating back what you heard, etc. Radio communication compensates for the lack of a more robust/sane way of exchanging information. There literally is no way for a controller to send you information in written format. Other than using their private phones. So, it all gets spelled out over low quality VHF radio. There's no good technical reason to not do something vastly more reliable, less intrusive, and less error prone. Some might say safer. Many planes have star link connections these days. The passengers get better connectivity than the pilot. They could be having video calls with the controller with crystal clear audio from anywhere on this planet instead of yelling to them over VHF only when they are in range. They could be sending each other emails, documents, digital maps, and lots of other machine readable information, etc. Not a thing. It's more a challenge of agreeing on what such a vastly better thing would be and then updating each and every plane and tower, airport, controller world wide with equipment that supports that. Add design by committee to the mix and the "state of the art" is something that would make any competent engineer born after 1970 blush.
- throw0101c 2y ago
  > A lot of radio exchanges are routine exchanges that involve very basic information: call signs, transponder codes, codes for approaches/departures, courses, altimeter settings, altitudes, weather information, etc. They are also in a fairly standardized format with reserved "keywords" for many important aspects of operation ("hold short", "line up and wait", "cleared to X"): * https://skybrary.aero/sites/default/files/bookshelf/115.pdf https://skybrary.aero/sites/default/files/bookshelf/115.pdf English is the lingua franca of ATC, but it is recognized it is obviously not everyone's first language.
- jcrawfordor 2y ago
  Honestly a lot of those recordings probably do sound a lot worse than the radio audio. I rarely see YouTube recordings that are as audible as the radio is in person. Here's what seems to be the reason: The common splitters you can buy to break out your headset connector to a recorder don't account for the signal level, which is very high on the headset connectors as aviation headsets are traditionally pretty high impedance. I've struggled with the headset audio blowing out even a fairly nice recorder (a Zoom) with the gain turned all the way down. Phones and pocket reporters don't even offer a gain adjustment and the recording can end up almost unusable. In a lot of YouTube videos of pilots, even most, it's pretty obvious that it's clipping at the recorder the whole time. Perhaps even worse, a lot of people are using like a GoPro with auto-gain, so you get the worst of both worlds: it ramps up gain until the noise is loud, and then when someone starts talking, it ramps down the gain, but a little too slowly, and it's still clipping even when it hits minimum. It's not very common to have trouble understanding the controller when in the air. AM radio at line of sight (as is the case when you're flying) is pretty robust. Maybe the hardest thing to understand are helicopter pilots because there's often rotor noise on their end.
- FL410 2y ago
  YouTube is not a good representation of what you hear in a headset. Half the time the mic taps aren't impedence matched and sound like shit. Besides that, most "controlling" (i.e. instructions that require action) comms have a handshake of sorts - the pilot repeats back the instruction for the controller to confirm. They don't just bark out instructions and hope you heard it, they listen for you to read them back, and will keep doing so until successful. So, even in cases when the comms are degraded, you will go back and forth until there has been positive confirmation (readback) you heard the instruction correctly (or they'll just give you a new frequency).