Expected rate of descent?

[Sphinx]

When you UK ATC people ask aircraft to descend what rate of descent do you require? And is this subtley different to the rate of descent you expect?

My understanding was that you plan on 1000 ft per min, but that aircraft can do what they like as long as it's at least 500 ft per min. Is my understanding correct? Thanks.

[Pierre Argh]

From my own perspective I don't recall ever having been told to expect or plan for a given rate of descent... we're used to aircraft going down at a reasonable rate. If it's not fast enough, or we require a specific objective we will tell you to "expedite" or to be at a certain level by a certain point... but am prepared to accept that might not be the whole story?

[knertius]

Hi there!
any new ideas on this topic? I´ve been having numerous discussions with my FOs about this. Quite a few of them seem to have a fetish for very low rates of descent (eg. 300fpm) when given a very early descent clearance. I heard somewhere that 1000 fpm is a minimum expected by ATC but I have not been in a position to have this verified by any official publication. I don´t want to tell the FO that he MUST descend at 1000fpm if I´m not in a position to prove that I´m right. I´m not based in the UK so answers from non-UK ATCs would also be appreciated!

thanks

[SM4 Pirate]

I don't expect any particular rate, but I would anticipate at least 500ft/min always, if I need to know the current VSI I'll ask for it, if I need improvement on that I'll ask for it.

"standard rate", oh my brain hurts,

The phrase “STANDARD RATE”, when included in a clearance, specifies a rate of climb or descent of not less than 500FT per minute, except that the last 1,000FT to an assigned level must be made at 500FT per minute.

In the case of a step-climb or descent, the specified rate will be applicable to all level clearances issued in the course of the step climb or descent. If unable to comply with the prescribed rate, the pilot in command must advise ATC.

But hey that may not be a 'standard thing' just down here in sleepy hollow.

[javelin]

I've always used 500 fpm as the minimum rate of descent.

Also, if controllers want me to start down at a silly range - outside the 3 or 4 times height distance, that is all you will get until you complain.

We are on fuel plans which calculate an optimum descent point but also include block standing agreements.

That said, I never go thin on fuel unless payload issues dictate, I am merely trying to conserve some of our $700 a tonne fuel !

The Americans are the worst......................... and yes they usually bleat after 3 or 4 minutes at 500 fpm :ok:

[Data Dad]

If it helps.....

From the UK AIP ENR 1-1-3-1

"2.2

Minimum Rates of Climb and Descent


2.2.1 In order to ensure that controllers can accurately predict flight profiles to maintain standard vertical separation betweenaircraft, pilots of aircraft commencing a climb or descent in accordance with an ATC Clearance should inform the controller if they anticipate that their rate of climb or descent during the level change will be less than 500 ft per minute, or if at any time during such a climb or descent their vertical speed is, in fact, less than 500 ft per minute.

2.2.2 This requirement applies to both the en-route phase of flight and to terminal holding above Transition Altitude.



Note:


This is not a prohibition on the use of rates of climb or descent of less than 500 ft per minute where necessary to comply with other operating requirements."

Regards

DD

[Scott Voigt]

Javelin;

We are the worst because we only start you down when we HAVE too and expect you to get down. We start you down for many things, sometimes it is trafffic, sometimes it is so that we can get speeds equal with a stream of traffic that is lower than you, sometimes it is to comply with a letter of agreement with another sector or another facility. We don't start you down for a whim. When you come over here, just remember that we do have about 70% of the worlds traffic when you count GA along with Air Carrier and Military. There are a LOT of folks out there...

regards

Scott

[javelin]

Hi Scott,
I don't mind being stepped down early, provided we have the information to pass through to our flight planners in order that Jepps can put it in the flightplan.
We have standing agreements at certain boundaries in the UK and these are incorporated into our plans.
Here is an example.
We take the A330 into SFB, Florida, we are given a reclearance flightplan from our company in order to keep fuel down and use - say Dulles as the alternate. I am not a fan of these plans because they can leave you thin at destination, so I normally calculate what I want to arrive in SFB w.r.t weather and traffic - Saturday is busy.
So, let's say I want to touchdown with 8 tonnes, (1500kg for a missed approach, another try, another go around, then still enough for Tampa.)
Now, from this figure, I add the burn, then the taxi and that should give me a good ramp fuel to depart.
This assumes econ to the ocean, .81 over the ocean, then back to econ.
If I am now surprised by a request for a descent to FL240, 280 miles out from SFB, instead of say 150miles, I start cutting into my comfort zone and therefore, I want to stay high as long as possible, so I go down at the minimum posted rod until you guys query it.
Put a couple of good thunderstorms in, a 767 and 747 in front and bingo, I am now on the ramp with 5 tonnes !
If there are standing agreements, let us know, if you want us down early, say why and when, we will do our best to comply.
I appreciate the US skies are busy, however not as busy as the European sectors we normally fly and at least we don't ask for ride reports all the time :ok:

[West Coast]

I wish they would ask. I've had my teeth rattled on speedbird more times than on those who do ask...

Anyway, to the issue. If there is enough captured data on early descents, then its up to your management to work with the controlling agency to find compromise.

[BOAC]

This thread dovetails with this (http://www.pprune.org/forums/showthread.php?t=227961). I had another one the other day, inbound and routing up the west country - "descend FL290" - 200+ miles before economical descent point. So, I start down from FL350 at 500fpm. I politely enquire "Are there any restrictions on the descent?" having not been given any to be met with a gruff and un-neccessary exchange involving the fact that 1500fpm or more was needed. Why not say so? Maastricht are generally pretty good in this respect - far less R/T time. It should by now, following these two threads, be plain to ATC that in the absence of a published altitude restriction, any early un-specified descent request WILL, as Javelin says, probably be conducted at 500fpm by most crews to try and protect their fuel reserves. A given rate or a 'level by xxx' will sort it all out.

[Scott Voigt]

Javelin;

Well if you routinely get an early descent then I would think that you would tell your company about it. There are far to many users of the system to try to go out and tell them all what to expect and why. Florida is a rather complex system due to MOST of the folks flying there not being over water equipped and don't want to go very far over it. Carrying all of that equipment means more weight thus more fuel. Then there is all the GA...

I don't know if you have been to one of our facilitiies or not, but trust me, Europe is NOT as busy. I have been to MANY European ATC facilities and they don't hold a candle to what we do here most of the time. They are busy, but it's mostly air carrier and not huge amounts compared to the flow through that we get. Our sector flow thorugh numbers are noramally higher too...

regards

Scott

[Asking]

2.2.1 In order to ensure that controllers can accurately predict flight profiles to maintain standard vertical separation betweenaircraft, pilots of aircraft commencing a climb or descent in accordance with an ATC Clearance should inform the controller if they anticipate that their rate of climb or descent during the level change will be less than 500 ft per minute, or if at any time during such a climb or descent their vertical speed is, in fact, less than 500 ft per minute.



I understand that in the US controllers anticipate short-term level-offs at 10000' to reduce speed to 250kts (it's mentioned in their AIM). I've not found anything similar mentioned in the UK AIP. Do controllers want us to tell them whenever we intend to carry out a level slow-down at FL100, or do they still expect a minimum ROD of 500fpm?

Thoughts?

[BOAC]

I have a vestigial memory that the 737 FMC provides 500fpm in all speed change manoeuvres.