Transponder output

[Etienne]

Hi

Noticed something funny in the Transponder serial output. The values are not bounded to -1200 to 31500'. If the pressure altitude drops below -1200' (highly unlikely, but none-the-less), the reported altitude sent to the transponder suddenly jumps to 31500'. I haven't been able to test it, but if the pressure altitude rises above 31500', my guess is that the reported altitude would wrap around back to -1200'...

Is this expected and common behaviour? It's likely to give some ATC's a heart attack ;D

Thanks
Etienne

 

[dynonsupport]

Not expected, but also not common. Even on a very low pressure day, within a short time of leaving the ground, you're probably off the bottom peg (that has the bug).

We haven't confirmed whether or not there's any wraparound on the high side (would require a bit more testing than we have readily at our desks), but it would only affect a few really high altitude customers that we have. We haven't heard any negative reports from those guys as of yet though.

 

[Etienne]

I wouldn't expect it to be a problem for 99.999% of the people out there, myself included!  

Just thought it was worth a note. Interesting also to note that the altitude tape behaves correctly, and bottoms out at -1200'...

Oh well - guess it's just another rare edge case ;D Thanks for looking into it...