RA calls inhibited?

[acannata]

Hi,

I'm performing manual circuits (FD off, AT off) at KJFK on G-BNLA.
On landing RA calls are absent. RA calls seems to be inhibited. Which is the reason?
Thank you.

Aldo

[Gary Oliver]

We too experienced this weekend.  Out of 16 legs, I think we missed call outs on approx 40% of flights.

Video evidence available. 

[tomenglish2000]

I had the same problem when I was doing circuits.

It turned out I wasn't going high enough in the circuit to re-enable the RA callouts. This is a deliberate feature.

http://aerowinx.com/board/index.php?topic=3431.0

Hope that helps.
Tom.

[tomenglish2000]

Although that doesnt explain why it was missing when you were flying Gary. Definitely above 1400' for those legs!

Tom.

[acannata]

Thank you!
I'm wondering which is the operational reason for callout reset.

Aldo

[Hardy Heinlin]

We too experienced this weekend.  Out of 16 legs, I think we missed call outs on approx 40% of flights.

I see no problem in my code: It resets above 1400 feet radio altitude.

What have you changed in your system since your last unproblematic flights? Does your scenery system inject correct elevation data into PSX without any short-term peaks to near-ground level?


Cheers,

|-|ardy

[Gary Oliver]

Most likely... We shall investigate.

[Hardy Heinlin]

I'm wondering which is the operational reason for callout reset.

Every one-time event needs a trigger condition and a flag that inhibits re-triggering. For example:

"If below 400 ft, do XY" -- Without an inhibit flag, the system would repeat the XY job continuously ... XY, XY, XY, XY, XY, XY ... as long as the aircraft is below 400 ft. We don't want this repetition.

"If below 400 ft and inhibit flag is off, set inhibit flag on and do XY" -- Here the system would do the XY job only once and never again. That's what we want.

However, as we need the XY job again on the next flight, the inhibit flag must be reset to off at some point.


Cheers,

|-|ardy

[acannata]

Hardy, thank you for the explanation. I was unable to find it on my manuals.
If I understand that logic, reset avoids disturbing and useless callouts during a GA.
Regards

Aldo

[Hardy Heinlin]

No. Such an approach call ("400", "300", "Minimums", etc.) is triggered when descending through the respective trigger altitude, not when climbing through the respective trigger altitude.

You also need to understand that there is an infinite test loop that checks the aircraft height every few milliseconds.

E.g. for "400" the trigger condition is not "if aircraft height = 400". That would not work because the check loop will most likely miss it. When it checks it every few milliseconds, the loop will receive random values like 412, 403, 397, 388 ... so it will never get exactly 400 for the trigger. That's why the trigger condition is "if aircraft height <= 400". When it receives 399 or 397 or whatever, the trigger will definitely occur. But it requires an inhibit flag after the initial trigger, otherwise you will every few milliseconds hear "400", "400", "400", "400", "400", "400", ... as long as the aircraft is <= 400 ft.


|-|ardy

[acannata]

Now the concept is crystal clear, at least for me!
Infinite test loop is the key.
Thank you again.
Cheers

Aldo