> Extremely bad to be messing with those frequencies. Potentially catastrophic.
If someone with a hobby electronics kit can cause that much damage, the system needs to change. Hobby projects like this can help expose the serious flaws in aircraft control, making us all safer.
Security by obscurity is no security at all. Security by hoping people don't do bad things is even worse.
I think what the comment is about is that the system should be built safer with less security with obscurity but more actual measures. You can (partially) scan people getting onto the plane for bombs etc but it's practically very hard to pinpoint a jamming RF transmitter possibly from kilometers away from ground. Security shouldn't rely on those frequencies being clear.
Because aircraft systems are multiply redundant, there is little likelihood of a jammer directly causing an accident.
However, any deterioration in that redundancy is considered a serious safety risk and immediate action is usually taken.
Bottom line: The high redundancy is there to prevent accidents, however any idiot who compromises that redundancy deserves to learn an expensive lesson.
This system does not at all rely on security by obscurity.
This system relies on safety be reliability / availability. All of the operating parameters are public, to prevent anyone from accidentally interfering with these systems. They are not designed against adversarial attacks, and really with radio systems. It is very hard to defend against jamming attacks. Doing so successfully makes the system a lot more complicated. More importantly, doing so successfully makes the system use much more bandwidth.
Bandwidth is actually really scarce. If you start doing defensive stuff, then more and more frequencies get used, and you end up with everyone screaming over each other just to be able to add all the required error correction. That is why we decided to coordinate on frequency allocation. It prevents a tragedy of the commons. As a side effect, it also means transmit power can be lower. This allows you to operate more systems in the same area without interfering.
Now, this does leave a somewhat fragile system. Because jamming (and other attacks) are not mitigated by the system. But this is an acceptable price to pay to actually allow people to use radio communication.
Besides, jamming attacks have an interesting downside. They are somewhat easy to track down. The higher level attacks can be defeated by cryptography. There is a mid-level of smart jamming, that attacks the low level protocols with more than just power. These require significant effort to develop though. And military hardware tends to have mitigations against this sort of thing. A sufficiently sophisticated attacker could disrupt civil systems, but to what gain?
It doesn't. Jamming TCAS or ILS systems doesn't cause crashes. At worst, a go-around and increased workload in the Tower.
But since you're disabling safety equipment or their redundancies, in practise it's rightfully treated as harshly as it is. TCAS almost never activates in practise but if your HAM radio jams it and a crash happens... You disabled that redundancy to prevent accidents.
If someone with a hobby electronics kit can cause that much damage, the system needs to change. Hobby projects like this can help expose the serious flaws in aircraft control, making us all safer.
Security by obscurity is no security at all. Security by hoping people don't do bad things is even worse.