Speed Reduction

[DICKUS]

If, for example, ATC request a speed reduction from 300 to 250 knots IAS; how quickly are they expecting it to happen?
Do you expect us to use full speed brake? Or is a more gentle and proffesional reduction in speed permitted by using the automatics to sort it out, which is after all what we want to do, to keep the passengers comfortable.

Secondly, occasionally, we are told to maintain a certain speed, but clearly, landing at 300 knots requires a longer runway than is presently available. It is presumably up to the crew's decision when to reduce speed appropriate for the approach, but they should then inform ATC?

[zkdli]

speed control

If you are told to reduce speed in the LTMA then you are expected to comply with the instruction as quickly as is practicable. Obviously we don't want to have everyone sitting in the cockpit with their noses stuck to the windscreen, but we also don't want you to take the next thirty miles to do it!
If you don't reduce the speed reasonably quickly it will only delay you in the long run as it will mean that you end up in the hold while spacing is sorted that way instead of on the run up to the hold.
When you are instructed to maintain a certain speed, in the LTMA at least, you are expected to maintain it until ATC tell you otherwise. This INCLUDES when you descend below FL100! speed control is a separation and any unannounced change of speed could cause a loss of separation. Some a/c cannot maintain high speeds at all levels and they should notify us if they are unable to comply! If you are instructed to maintain a speed with our approach units, on final approach the instruction will include a distance from touchdown where the speed control ceases e.g. 160 knots to four DME.:O

[Short Approach?]

If you are told by app. to maintain hign speed eg. 300 knots, we are aware, of course, that you have to reduce at some point. But as this point varies quit a bit from company to company, airframe to airframe, driver to driver, please give us a call when starting to reduce. We can then if needed issue a new restriction.. :p

[jocko0102]

Unless you are Ryanair in which case they do what they want which means as fast as poss until the plane is on stand.Not really what we need.

[cossack]

As has been said earlier, slow as quickly as you comfortably can.
If you are under positive speed control then deviating from the assigned speed without requesting it is really a no no. If you have an operational reason (i.e. turbulence) then state it and no controller should refuse this request.

A real bugbear of mine is those who slow from an assigned speed without a word. 180kts 20 miles from touchdown is unreasonable in most circumstances when there is a lot of traffic about. I'm sure you'd get a bit miffed if we slowed you to 180 with 20 to go every time wouldn't you?

I have never had any problem with Ryanair. They invariably fly what is asked and will often fly faster for longer than other similar types if requested/permitted. This permits more flexibility on the part of the controller and often allow a sequence to be run more effectively than could have been the case with everybody slowed up.

[Vlad the Impaler]

At the end of the day, as mentioned before, speed control is a form of separation and if you deviate from that speed it can be at the worst, dangerous. As controllers, our end of the bargain is to allow to trade off in the speed/height equation and not ask the impossible. It is also the responsibility of the controller to follow it through, ie, if a plane comes on doing 325 indicated from an area sector to the TMA, unless we change it you could, and should hit the hold at that speed, so we must reduce your speed if necessary to an appropriate holding speed or whatever we can co-ordinate with the approach controller. The bottom line is please fly the assigned speed and ask before doing anything else, it is after all, your arse you will be saving........

[FWA NATCA]

DICKUS,

It depends, if I sounded like I was panic mode, you better slow down as fast as you can, If I sound all calm and under control, take your time.

In all seriousness, I use speed control to maintain seperation, not to create seperation. If I ask you to say slow from 250 kts. down to 190 kts, then I'm looking for your speed to be at 190 kts within 6 miles or less, I try to allow one mile per 10 knots of speed reduction.

I also don't expect you to be able to descend and reduce so I will do one or the other first, example, Reduce speed to 210, then descend and maintain, or descend and maintain, and when able reduce speed to.

Since I'm not an en-route person I'm not familiar with mach speeds and how long it takes you guys to slow down.

Mike

[5milesbaby]

In area when coming off a Mach number you will normally be told 'when able IAS ***kts' so to restrict all of descent. If you were in trail in this circumstance, the first would get 300kts, and the 2nd probably 280 or less, the 20 kts builds in the different descent rates and altitudes we see, and normally fine adjustments just aid confirming the separation needed.