Reduce speed at 1kt/sec?

[huckleberry58]

When you ask us to reduce speed do you expect a certain rate of reduction? I was told 1kt/sec is expected. True?

[celeritas]

I've always worked on around 10kts per 1nm. Generally seems to work (although you do need to take winds and aircraft types into account); give it a whirl and let me see what you think!!

[huckleberry58]

Hi. Are you talking about descent profile or answering my question? Yeah, i use that as part of my calculation to check my descent profile which can be achieved easily in level flight but may not be so easy when in VNAV with speed intervention or using FLCH. What i would like to know is if ATC expect a minimum rate of reduction of speed when we are asked to slow down. Thanks.

[Bandbox4Training]

Personally, I would expect you to be at the requested speed by the time you were FL270 or below as soon as comfortably possible, but to be honest I've never thought about a rate of reduction.
Bear in mind that you are obviously being speeded for a reason, and by observing other aircraft we can relate their speed to yours. If the speeds aren't working I'll just use extra vectors to create more space.
Hope that helps?

[IMHFO]

H58

The ATC texts tell us to expect 1 knot/sec however this factor is really only a warning to less experienced controllers regarding unrealistic expectation.

Speed reductions can be anything from a rough best hope/guess to something system based like Maestro that is also, at best, a pluck. More experienced flow controllers will be manually feeding in many other variables such as known/forecast winds and variance at the different levels, IAS/TAS relationship, normal operator performance and compliance and even 'known voice' confidence. Same type aircraft flown by different operators, differently, can have a great influence. One thing is for sure, if what we want is not what we are seeing then expect a vector to get it right. Not discounting the use of combined vector/speed to permit you to maintain descent profile. Done well, flow is elegant to watch; done badly - well you all know about that.

[chevvron]

1 kt/sec is the PFA recommendation for speed reduction to test stalling speed; has someone got their wires crossed?

[IMHFO]

No,

The ATC texts tell us to expect 1 knot/sec

[ATSAWHO]

Get a life BOYS!

[chevvron]

What I meant was who cares? I just watch the groundspeed readout on my radar and adjust accordingly, it really doesn't matter what rate of speed reduction is used, that's the job of the pilot not the controller.

[MancBoy]

When LACC gets mode S in a few years then there won't be any hiding for those pilot colleagues of ours who don't quite tell the truth!!

[huckleberry58]

we're allowed +/- 10kts. :}

[MancBoy]

Where does it say that then?

Not in any of our MATS part 1 or 2's.


What's the point of issuing speed control instructions then if they aren't needed to be followed?

If i tell you to do 250 IAS or 310 IAS I expect you to do it.

Not 240/260 or 300/320!

[huckleberry58]

Pilots complying with speed adjustments are expected to maintain a speed within plus or minus 10 knots or 0.02 Mach number of the specified speed.

http://www.pilotfriend.com/aero%20information/ATC4.htm

[Gonzo]

Which publication is that?:confused:

[zkdli]

Huckleberry,
That may be correct in general. However, the UKAIP specifically states for LHR, STN, LGW, LTN that pilots are to fly ATC speed instructions precisely and that they are to adjust to the speed as quickly as practicable. All speeds are mandatory and if a pilot is unable to fly the speed instructed they are to advise ATC ASAP.:)

[huckleberry58]

I do whatever you guys tell me, you seem to know what you're doing! :E
Keep up the good work! :ok: