In Tracon 2012, what are reasons aircraft would refuse a slow command?

[pinback]

My approach guys are continually telling me "negative" even for reasonable requests like "reduce speed to 250 knots".  Any idea why?

[707FAN]

I have found that the syntax to get them to slow down is quite difficult and have not had much success at it. You have to be very specific with the commands.

Talking to ATC controllers in Aus. they say that speed control is not usually used or needed after the A/C are on tower freq as they should be separated by the approach controller. Also listening to US ATC on Live ATC & monitoring various airports, I do not hear speed control used much at all.

Kev M

[pinback]

I did find out you have to say "knots" at the end, but even with that, they often refuse.  No biggie, like you said.  (However, I listen to KLAS on an almost nightly basis, and speed commands are given on a regular, almost continual, basis.)