Speed reduction

[littlejet]

when ATC requests from pilots to reduce speed in the approach area say from 270 to 210 kts what is the deceleration rate ATC needs? Any reference document for that?
Thnx

L.

[Tarq57]

In our manual the suggested rate we can reasonably expect is about 1 knot per second, with a suggestion that this might not be achieved if the aircraft is descending/clean.
Once dirty the expected rate is a bit higher.
There is no mention of a required deceleration rate.
Our MATS was originally based on the English one, and this hasn't changed in the time I've been a controller, so I doubt it's different in Europe.

[Antek]

Likewise - our (UK ATC) simulator is programmed for speed reduction at about 1kt/sec for medium size airliners.

Also, that's what I was taught many years ago as a rule of thumb. Mind you, aircraft are a lot cleaner these days. Also, I'd think it could make quite a difference if there are a couple of big prop discs sticking out (ATR, DHC8 etc).

[autopilot_off]

Also, I'd think it could make quite a difference if there are a couple of big prop discs sticking out (ATR, DHC8 etc). In level flight they do indeed help a lot but in the descent they're about as much use as a chocolate fireguard! With a rate of descent anywhere above -1600fpm we're lucky to lose any speed at all.

[PaulW]

I guess it depends on type, Saab 2000 will happily slow down with v/s up to 2500. Neutral torque flight idle descent ie 10-15 power units,which is about 3000 feet a minute 5.0 descent at 370kt Tas and will hit all the standard speeds ie 250 below fl100 230 in zone 210 on downwind 180 on base without touching power levers all the way down (950 rpm in crz pwr mode, no prop levers on Saab) maintaining 5.0 degrees with v/s as groundspeed slows. That's without even discing the props by closing the power levers let alone using the never normally used high rpm ice shedding mode which is 1100 rpm. So even with high rates of descent the Saab will slow. So keep our speed up please thank you and let us be number one please.. We can maintain 250 to final (if light short final) and still be stable through standard configuration at 1000 with a continuous descent. 3.0 CDA speed control is a no problem in this fine aircraft.