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It is worth mentioning that transport aircraft carry Mode S [0] transponders which emit a unique ICAO 24 bit address assigned by aircraft registration. This dat

It is worth mentioning that transport aircraft carry Mode S [0] transponders which emit a unique ICAO 24 bit address assigned by aircraft registration. This data is available regardless the pilot-entered 4 octal digit Mode A transponder code. The transponder can still be turned off, however. This contrasts to small aircraft which typically have Mode A/C only (no mode S). [0] http://en.wikipedia.org/wiki/Aviation_transponder_interrogation_modes http://en.wikipedia.org/wiki/Aviation_transponder_interrogat...

samstave 13y ago
So.... why? All airplanes should have a MAC address. No plane should have a user-servicable-power-switch to the transponder. Can you tell why the opposite woud be needed?
- maxerickson 13y ago
  In case an electrical fault is detected. Protecting the passengers from the pilot is anyway a false goal. You can't really do it without removing the pilot.
  - samstave 13y ago
    This and: (electrical faults, interference with airport radars, safety of maintenance technicians). Sound like utter BS. Show me a case where an IN-FLIGHT transponder shutdown is a needed issue, or where this does not need a better engineered solution. Also - Don't tell me why this is not done (based on past issues) - tell me why this is impossible to fix. I challenge you to give me any reason in the universe which is acceptable for not tracking, in real time - uninterrupted streams, flying packages of hundreds of humans. Give me any reasonable response to why this is not something that should be fixed.
    - maxerickson 13y ago
      It's obviously not possible to give you a response that you find reasonable, so why bother trying again? But an electrical fire in a plane is sort of a real problem that there needs to be contingencies for. Planes doing something strange doesn't happen often enough for it to be the most important thing in the universe.
      - samstave 13y ago
        Obviously - so thanks for being defeatist.
        einhverfr 13y ago
        I don't think it is defeatist. The whole point of security is risk management. You address your most common risks first, and then the less common risks later. Electrical fires are more common than hijackings, especially after you figure in airport security. Therefore in plane design you worry about electrical fires far more than you do hijackings. Additionally this is the first incident of its kind. This is not a typical hijacking. In fact it is entirely unprecedented. For this reason it is a game changer, and I think you are right to point that out. But electrical fires are orders of magnitude more common so you aren't going to ever risk one based on a much less likely possibility here. To be honest, I have faith that investigators will eventually track the culprits down. Then once we know who and why we can decide what to do about it. However consider what is required to pull this off: 1. Having an airport capable of landing a 777 that nobody knows about 2. Having refuling equipment and fuel. 3. Having a hangar capable of storing the 777 out of the eyes of satellites. These are not small requirements. Whoever did this was quite prepared. It was not pilot suicide based on the data we have. Whoever did this was large, organized, and had tons of resources (we are talking about a large drug ring or a small country here). Against a determined enemy like that I don't know that you really can stop them at the plane. Instead you need real defence in depth, and we can't even talk about that until we know more.
    - Perdition 13y ago
      >Show me a case where an IN-FLIGHT transponder shutdown is a needed issue How would the system determine it is in-flight and thus prevent a maintenance shut down? You would need another device to determine in-flight from ground operations, and thus another device that can malfunction and thus can be defeated by an attacker. >Give me any reasonable response to why this is not something that should be fixed. Give me a reasonable response why spending a bunch of money to fix this rare issue is worth it over other safety improvements? Old aircraft, poor maintenance, and overworked pilots kill many times more people than hijackers. P.S. Why don't we track buses? Why don't we track cars? Why don't we track everybody?
      - samstave 13y ago
        >P.S. Why don't we track buses? Why don't we track cars? Why don't we track everybody? Buses are at alt==0 and never over an ocean - you're an idiot for comparing the two. Why don't we track everybody? Do you understand what the NSA has been doing?
        ColinWright 13y ago
        I'm sure you have valid points to make, but I would ask that you reconsider how you make them. From the guidelines[0]: In Comments Be civil. ... When disagreeing, please reply to the argument instead of calling names. E.g. "That is an idiotic thing to say; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3." [0] http://ycombinator.com/newsguidelines.html http://ycombinator.com/newsguidelines.html
        Perdition 13y ago
        >Buses are at alt==0 and never over an ocean And what does that have to do with it? In the event of a passenger jet crashing into the ocean an enhanced transponder system would not raise passenger survival by any notable rate (because aircraft crashes where the passengers survive and aren't immediately rescued are incredibly rare in the modern age). Aircraft hijacking where the craft and passengers go missing is incredibly rare even among hijacking incidents.
      - michaelt 13y ago
    - lutusp 13y ago
      > Show me a case where an IN-FLIGHT transponder shutdown is a needed issue, or where this does not need a better engineered solution. Certainly. There's always more than one transponder on board a big jet, for safety and redundancy reasons. If a transponder begins to misbehave, it might position the aircraft incorrectly on the ATC screen, very dangerous, or the transponder could be getting bad information from the altimeter (class C transponder), which would cause ATC to paint the aircraft at the wrong altitude -- also very dangerous. These are just two reasons among many, for flight deck officers to require an immediate way to disable a transponder. > Give me any reasonable response to why this is not something that should be fixed. There's something you need to understand about the relationship between an aircraft and its pilot. The aircraft is designed to protect the pilot and the passengers, not the other way around. All this talk about protecting the aircraft from the pilot and passengers has it backwards. Obviously this means if a pilot goes crazy or someone unauthorized gets into the cockpit, the results can be catastrophic.
    - dingaling 13y ago
      > Show me a case where an IN-FLIGHT transponder shutdown is a needed issue When changing squawk codes, it is procedure at most airlines to put the transponder into stand-by mode. This prevents inadvertent transmission of incorrect squawks should the pilots mis-key. e.g. once squawk 7500 Hijack is transmitted, ATC must implement appropriate measures regardless of what the crew subsequently do or say. Consider that fact given 7050 is a valid non-emergency squawk. Once the squawk has been confirmed as correct the transponder is returned to active status.
    - davepage 13y ago
      If you have a look at the FAA AIM, there is controller phraseology "squalk standby" which means to disable the transponder. This is to be used when the transponder is seen by the controller to be emitting unreliable or incorrect information. Keep in mind the transponder system design originated in WW2 and is quite crude. The crew and controllers are the main form of error detection and correction.
- Perdition 13y ago
  Transponders are active radio transmitters, there are plenty of situations where they need to be shut down (electrical faults, interference with airport radars, safety of maintenance technicians). A plane being hijacked in this way is so incredible rare that having always-on transponders is not worth the safety trade off.

samstave 13y ago

So.... why? All airplanes should have a MAC address. No plane should have a user-servicable-power-switch to the transponder. Can you tell why the opposite woud be needed?

maxerickson 13y ago
In case an electrical fault is detected. Protecting the passengers from the pilot is anyway a false goal. You can't really do it without removing the pilot.
- samstave 13y ago
  This and: (electrical faults, interference with airport radars, safety of maintenance technicians). Sound like utter BS. Show me a case where an IN-FLIGHT transponder shutdown is a needed issue, or where this does not need a better engineered solution. Also - Don't tell me why this is not done (based on past issues) - tell me why this is impossible to fix. I challenge you to give me any reason in the universe which is acceptable for not tracking, in real time - uninterrupted streams, flying packages of hundreds of humans. Give me any reasonable response to why this is not something that should be fixed.
  - maxerickson 13y ago
    It's obviously not possible to give you a response that you find reasonable, so why bother trying again? But an electrical fire in a plane is sort of a real problem that there needs to be contingencies for. Planes doing something strange doesn't happen often enough for it to be the most important thing in the universe.
    - samstave 13y ago
      Obviously - so thanks for being defeatist.
      - einhverfr 13y ago
        I don't think it is defeatist. The whole point of security is risk management. You address your most common risks first, and then the less common risks later. Electrical fires are more common than hijackings, especially after you figure in airport security. Therefore in plane design you worry about electrical fires far more than you do hijackings. Additionally this is the first incident of its kind. This is not a typical hijacking. In fact it is entirely unprecedented. For this reason it is a game changer, and I think you are right to point that out. But electrical fires are orders of magnitude more common so you aren't going to ever risk one based on a much less likely possibility here. To be honest, I have faith that investigators will eventually track the culprits down. Then once we know who and why we can decide what to do about it. However consider what is required to pull this off: 1. Having an airport capable of landing a 777 that nobody knows about 2. Having refuling equipment and fuel. 3. Having a hangar capable of storing the 777 out of the eyes of satellites. These are not small requirements. Whoever did this was quite prepared. It was not pilot suicide based on the data we have. Whoever did this was large, organized, and had tons of resources (we are talking about a large drug ring or a small country here). Against a determined enemy like that I don't know that you really can stop them at the plane. Instead you need real defence in depth, and we can't even talk about that until we know more.
  - Perdition 13y ago
    >Show me a case where an IN-FLIGHT transponder shutdown is a needed issue How would the system determine it is in-flight and thus prevent a maintenance shut down? You would need another device to determine in-flight from ground operations, and thus another device that can malfunction and thus can be defeated by an attacker. >Give me any reasonable response to why this is not something that should be fixed. Give me a reasonable response why spending a bunch of money to fix this rare issue is worth it over other safety improvements? Old aircraft, poor maintenance, and overworked pilots kill many times more people than hijackers. P.S. Why don't we track buses? Why don't we track cars? Why don't we track everybody?
    - samstave 13y ago
      >P.S. Why don't we track buses? Why don't we track cars? Why don't we track everybody? Buses are at alt==0 and never over an ocean - you're an idiot for comparing the two. Why don't we track everybody? Do you understand what the NSA has been doing?
      - ColinWright 13y ago
        I'm sure you have valid points to make, but I would ask that you reconsider how you make them. From the guidelines[0]: In Comments Be civil. ... When disagreeing, please reply to the argument instead of calling names. E.g. "That is an idiotic thing to say; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3." [0] http://ycombinator.com/newsguidelines.html http://ycombinator.com/newsguidelines.html
      - Perdition 13y ago
        >Buses are at alt==0 and never over an ocean And what does that have to do with it? In the event of a passenger jet crashing into the ocean an enhanced transponder system would not raise passenger survival by any notable rate (because aircraft crashes where the passengers survive and aren't immediately rescued are incredibly rare in the modern age). Aircraft hijacking where the craft and passengers go missing is incredibly rare even among hijacking incidents.
    - michaelt 13y ago
  - lutusp 13y ago
    > Show me a case where an IN-FLIGHT transponder shutdown is a needed issue, or where this does not need a better engineered solution. Certainly. There's always more than one transponder on board a big jet, for safety and redundancy reasons. If a transponder begins to misbehave, it might position the aircraft incorrectly on the ATC screen, very dangerous, or the transponder could be getting bad information from the altimeter (class C transponder), which would cause ATC to paint the aircraft at the wrong altitude -- also very dangerous. These are just two reasons among many, for flight deck officers to require an immediate way to disable a transponder. > Give me any reasonable response to why this is not something that should be fixed. There's something you need to understand about the relationship between an aircraft and its pilot. The aircraft is designed to protect the pilot and the passengers, not the other way around. All this talk about protecting the aircraft from the pilot and passengers has it backwards. Obviously this means if a pilot goes crazy or someone unauthorized gets into the cockpit, the results can be catastrophic.
  - dingaling 13y ago
    > Show me a case where an IN-FLIGHT transponder shutdown is a needed issue When changing squawk codes, it is procedure at most airlines to put the transponder into stand-by mode. This prevents inadvertent transmission of incorrect squawks should the pilots mis-key. e.g. once squawk 7500 Hijack is transmitted, ATC must implement appropriate measures regardless of what the crew subsequently do or say. Consider that fact given 7050 is a valid non-emergency squawk. Once the squawk has been confirmed as correct the transponder is returned to active status.
  - davepage 13y ago
    If you have a look at the FAA AIM, there is controller phraseology "squalk standby" which means to disable the transponder. This is to be used when the transponder is seen by the controller to be emitting unreliable or incorrect information. Keep in mind the transponder system design originated in WW2 and is quite crude. The crew and controllers are the main form of error detection and correction.
Perdition 13y ago
Transponders are active radio transmitters, there are plenty of situations where they need to be shut down (electrical faults, interference with airport radars, safety of maintenance technicians). A plane being hijacked in this way is so incredible rare that having always-on transponders is not worth the safety trade off.