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No reaction from ATC on transponder failure


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Hi Everyone,

 

I'm relatively new to FSX and I wanted to give a try some equipment failure for the first time. I've chosen transponder failure. The flight was IFR to Frankfurt International (EDDF) with heavy thunderstorm weather scheme.

 

After receiving approach pattern and contacting Frankfurt Tower I activated transponder failure.

I'm aware that in case of radio problems I should set transponder to squawk code 7600 but in my case it was the transponder failure so I wouldn't expect any effect, no matter how I try to set my transponder.

I was rather expecting that ATC will contact me to notify me that they aren't getting data from my transponder anymore and eventually give instructions on how to stay safely away from other traffic.

 

Waiting for any contact from them (my ATC window didn't have any option to tell them about the problem) I continued approach following the last order from the tower. I was unable to visually recognize the incoming danger. The tower didn't also try to warn other aircrafts about unrecognizable traffic (me).

So the flight ended by being hit by another landing aircraft.

 

A couple of question arise:

1. Forgetting about that I used simulator option to trigger transponder failure, would I be able as a pilot to always recognize that my transponder stopped working?

2. Is it expected from ATC to remain silent if one of the IFR flights stops transmitting data from transponder?

3. Should I try to switch to squawk code 7600 anyway? And would that make any difference if the transponder was down.

4. What else could I do to avoid the crash?

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Interesting that ATC did not notice the transponder failure. The only time ATC ever notified me was when I was playing around in the cockpit after setting the initial transponder freq, I tuned it to another freq and got an immediate response from ATC that I was squawking the wrong freq.

 

My thoughts that in the real world ATC would be on you quickly if they lost your transponder signal. If you were in the pattern for landing, I would bet you would be given priority and any other aircraft would be cleared out of the path. In the Sim, you are up the creek and no paddle to be found;)

Still thinking about a new flightsim only computer!  ✈️

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Thank you for your response.

Exactly, very interesting. I will retry this scenario and try to emit squawk code 7600 - maybe this will trigger something.

I will also try going below cloud base hoping for visual contact with the tower but hey, they do have radar at EDDF, don't they?

If it's a bug then it's quite disappointing.

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Thank you for your response.

Exactly, very interesting. I will retry this scenario and try to emit squawk code 7600 - maybe this will trigger something.

I will also try going below cloud base hoping for visual contact with the tower but hey, they do have radar at EDDF, don't they?

If it's a bug then it's quite disappointing.

 

I just tried a quick test at KSFO in my 737. I set the transponder failure to happen in 5 minutes. I got my IFR info from Clearance/Clarence and set the proper freq. While the transponder was operational, I did change the freq and got an immediate response from Ground to change it back. When the failure occurred the Transponder was dead and no contact from ATC in regards to it. Must be a flaw in the Sim!

Still thinking about a new flightsim only computer!  ✈️

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I did the experiment. Changing squawk to 7600 had no effect as expected. Going below the cloud base resulted in "cleared to land" when I was quite close to the airport and I was able to see the details including tower. I'm still not sure if it was because the tower "spotted" me or faulty transponder was still mishandled by the simulator.

There was also no traffic alert but maybe there was simply no aircraft close enough to cause collision danger.

The conclusion is that at least to some extent it doesn't work realistically.

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To test you could: fail transponder- request flight following- see if they accept your transponder.

 

I have a feeling these type of failures affect gauges. Just like the failure of the althoduer affects the main gauge, but not the standby alt, and not the red lettering altitude at top of the screen.

So I expect with the squak gauge gone, you can still select the squak from the atc menu and have fsx set it for you that way.

[sIGPIC][/sIGPIC]
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7600 does nothing special in fsx. You either have the correct code, or you don't. If you have the wrong code you get told to change it back.

 

Atc is very basic. You can't declare emergency either.

[sIGPIC][/sIGPIC]
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OP, you're expecting too much realism from a very mundane Sim with a craptacular ATC. Check my, "If I won the lotto" thread. LOL! :D

 

Yeah, the only time I had ATC say anything to me about my squawk was when I changed its code.

 

Also note, the squawk code is not a frequency. It's exactly what it says: a code. It's actually PCM ( Pulse Codded Modulation) and transmits on 1090 MHz. So 1090 MHz is the frequency. Everyone uses (or typically uses) 1090 MHz. It's just that each aircraft has a different PCM coded signal sent from their plane. So a squawk code of 4780 is 4,780 pulses per second. If I can remember right.

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Yes, unfortunately you all confirm my findings. FSX ATC is a crap. The only effect of setting squawk code to 7500, 7600 or 7700 is that ATC won't complain. Aircraft hijacked? So what? Radio problem? Keep calm. Emergency? Don't bother us.

Don't know how this should work. If the transponder fails you can't squawk anything.

Furthermore 7600 is the code for COM fail.

It's quite obvious why there's no squawk for a transponder failure ;)

Yes, exactly. I was aware from the very beginning if you read the first post. I just wanted to see if there's any way to force FSX ATC to notice the problem. You know, transponder in FSX is not a real broken device but just a piece of software. As a programmer I can assure you that nothing can stop a software transponder from sqawking 7600 to a software ATC despite it's not working, if a software developer overlooked it ;)

It seems like the only implemented behaviour of ATC is: in case of 7500, 7600 or 7700 don't ask the pilot to set correct squawk code...

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Also note, the squawk code is not a frequency. It's exactly what it says: a code. It's actually PCM ( Pulse Codded Modulation) and transmits on 1090 MHz.

It's not radio frequency but PCM frequency - I knew that. The carrier and a message are two different things. Therefore you can transmit 4,780 pulses per second (everything what happens periodically "per second" actually has a frequency measured in Hz) via the carrier which is radio frequency 1090 MHz. But don't get me wrong. Your clarification is valuable. Thanks for it.

And thank you all for the activity in this thread.

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  • 1 year later...

I was in the middle of an IFR flight when I read this thread, so I decided to try it. I failed the transponder and got nothing from ATC. Even though the gauge was dark, I clicked on the window to change the code, and ATC informed me immediately that I had an incorrect squawk.

 

So... Apparently, failing the transponder does nothing but fail the display. Otherwise, it appears to be functioning as it should.

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