descent question for the ATC guys

[Sage]

When given a clearance to descend, what is the minimum rate of descent do you use for planning purposes? I've heard 500 fpm, 1000 fpm, 1500fpm, and fpnm (equated to somewhere around 1600-1700). Additionally, when climbing below 500 fpm, do you requre a "slow climb" call? Thank god the last one doesn't happen anymore not like in the last aircraft I flew.

Thanks!

[Braun]

I work a terminal airspace and therefore use a tool called VMR (Vertical Movement Rate...something like that) and this is displayed on the aircrafts data tag which allows me to have a really good idea of your current FPM. So that being said you get used to the aircraft types and their respective rates of climb. That being said there isn't really a magic number. I see it as common sense, if you are flying an A320 and are going to climb at 800 fpm instead of a normal rate for your aircraft type than it would be nice to know. Inversely if you are flying a B1900 and want to climb at 3500fpm it would also be nice to know. So basically if you are going to be climbing at a rate much different than the usual for your aircraft type just let us know.

[Braun]

I read your post too fast and saw it was for descent rates. Oops! In that case you get used to The different aircraft profiles and companies that all have a different way to the way they fly their aircraft. A good example is American pilots are always low and slow while the canadian companies tend to be high and fast. But once again there is no magic number.

[invertedattitude]

For the record, not just terminal controllers use VMR's

When I issue an aircraft a descent I expect at LEAST 500FPM... all of that being said, if I need you to descend at a certain rate for traffic I'll either issue a specific FPM, or just "Reach FLXXX within X minutes"

[Braun]

I know not just terminals use VMR, just sayin where my experience with the matter comes from!

[husky]

We all get used to certain aircraft types and performances. I expect certain aircraft to perform a certain way, but part of what makes ATC interesting is that things aren't always what you expect. We are watching your descent rates, and if we require a faster/slower rate of descent, we will generally let you know. The onus is not on the pilot to let us know their descent rate.

[the_professor]

When given a clearance to descend, what is the minimum rate of descent do you use for planning purposes? I've heard 500 fpm, 1000 fpm, 1500fpm, and fpnm (equated to somewhere around 1600-1700). Additionally, when climbing below 500 fpm, do you requre a "slow climb" call? Thank god the last one doesn't happen anymore not like in the last aircraft I flew.

Thanks!

You must have been flying the CRJ then. What a POS climber. It's got to be the only jet on the planet whose climb rate is exceeded by the 172, if you're talking about its performance above FL240 or so. Absolutely laughable.

Controllers expect whatever the average/norm is for the type, and that's one reason why the job can be hard to learn. A competent controller learns the fairly subtle nuances of how dozens of types perform, and uses that in their planning. There are some radical differences when it comes to descent profiles (and climb profiles too, for that matter) among what people might otherwise think are "the same type of plane", i.e. 737 vs 320, etc. You can generalize into categories to some degree (turboprop, airliner, bizjet, fighter, single piston, twin piston), but when it comes down to complex scenarios, it is performance knowledge that can make or break a plan.

There should be no requirement for a call to the controller, as altitude separation is not based on anticipated performance. An altitude clearance means that the altitude is available right now, regardless of whether you climb (or descend) like an F-18, or like the aforementioned wounded RJ trying to get to anything above 260. If they need you to make a certain restriction, that restriction should be issued with the clearance.

However, it's a nice courtesy if you're planning a simulated emergency descent, or if you have limitations due to a pressurization issue, etc.

[old_man]

Reminds me of a story I heard once of a controller repeatedly asking an F18 what his heading was, he replied "I'm not heading, I'm climbing".

Probably an urban myth however.

[parrot_head]

There should be no requirement for a call to the controller, as altitude separation is not based on anticipated performance. An altitude clearance means that the altitude is available right now,

I, and the controllers I work with, quite often base separation on anticipated performance. For example if I had an E190 climbing thru 9500' for FL 250 and a BE190 was departing underneath at 3000', or even 5000', needing FL 190, I'd clear the BE190 all the way up. Of course we monitor the situation to make sure things stay where we want them and it, obviously, depends on the aircraft types involved.

Controllers are creatures of habit and often base decisions on past experience, if you are going to try something that is out of the norm for you (we do get used to different pilots/companies flying in certain ways) or you aircraft type, it might be worth a note.

[invertedattitude]

Don't forget not just types but airlines...

Ask WestJet for a "good rate of descent" then ask Air Canada... Nowhere near the same, and it's not just type difference either.

[the_professor]

I, and the controllers I work with, quite often base separation on anticipated performance. For example if I had an E190 climbing thru 9500' for FL 250 and a BE190 was departing underneath at 3000', or even 5000', needing FL 190, I'd clear the BE190 all the way up. Of course we monitor the situation to make sure things stay where we want them and it, obviously, depends on the aircraft types involved.

I'm sure Transport would be interested to hear this, because you cannot do that unless you already have the required radar separation, making the vacated altitudes irrelevant.

What's your licence number, and what ACC do you work at?

[the_professor]

Don't forget not just types but airlines...

Ask WestJet for a "good rate of descent" then ask Air Canada... Nowhere near the same, and it's not just type difference either.

Then why not ask for something specific? A "good rate of descent" is impossibly vague and open to interpretation, hence the different results produced.

Try something like "Maintain a descent rate of 2500fpm or greater until through XX altitude" and you'll get what you need every time.

[invertedattitude]

Agreed professor, but sometimes I just say "good rate" because I want them to get moving, traffic might not be imminent, but it might be if they fool around starting descent like many airlines tend to do.

Sometimes I'll give a "good rate" even when I have lateral separation established via vectors, just so I can get everyone on course faster but safety is not affected. Just a couple of reasons why I might use it, to each their own however...

Also your comment "Hence the different results" I don't really agree, if you tell WestJet "Good rate of descent" it's usually 4000FPM +, I've never seen any other airline/aircraft type accomplish the same when asked... I'm not saying they are doing anything wrong, just different SOP's or something I assume, we've even seen 737-700's descending at 6500FPM+ a little excessive for normal ops IMO, but nevertheless helpful.

Also I'd like to think that Parrot doesn't mean that the aircraft is literally "underneath" at least I hope so, because as you said, not legal.

[parrot_head]

you cannot do that unless you already have the required radar separation, making the vacated altitudes irrelevant.

So if you have a King Air 100, in a radar environment, at 14000 ft climbing at 500 ft/min to FL190 and a Caravan, or even another King Air 100, calls you climbing thru 5000 ft at 500 ft/min requesting 15000 ft you are going to only clear the guy to 13000 ft until the above aircraft vacates 15000 ft?

Never mind getting my license suspended, if I controlled like that I would have never got a license in the first place.

[burly]

Professor I'm going to take a wild guess and say your an enroute controller.

[tdi_ywg]

So if you have a King Air 100, in a radar environment, at 14000 ft climbing at 500 ft/min to FL190 and a Caravan, or even another King Air 100, calls you climbing thru 5000 ft at 500 ft/min requesting 15000 ft you are going to only clear the guy to 13000 ft until the above aircraft vacates 15000 ft?

Never mind getting my license suspended, if I controlled like that I would have never got a license in the first place.

If they are separated by 5 (or 3) miles, then yes. If not, then you must ensure that the a/c are in contact with each other and instruct them to maintain at least 1000' vertical separation from each other. Useful if they are company, similar or same type, and within a couple or few thousand feet of each other.
Other option, which can be a pain, is to ladder the lower a/c up. It's a pain, but legal.

Perhaps you should have a look at the big blue binder.

[invertedattitude]

Enroute or not, if they are less than 3 or 5NM depending on your airspace laterally you can't clear a guy through his level... besides if he's climbing at 500FPM from 5000 to 15000, if you cleared him to 13000 I think you have a bit of time to wait for the top guy to vacate 15?

[Braun]

I don't think I would ever use that visual separation stuff with 2 IFR aircraft. As for clearing an aircraft through the passing altitude of a faster climbing or descending aircraft, as much as it is safe it is not legal.

MANOPS 472.3 I believe, unless it's changed.

[the_professor]

Professor I'm going to take a wild guess and say your an enroute controller.

Relevance?

[the_professor]

you cannot do that unless you already have the required radar separation, making the vacated altitudes irrelevant.

So if you have a King Air 100, in a radar environment, at 14000 ft climbing at 500 ft/min to FL190 and a Caravan, or even another King Air 100, calls you climbing thru 5000 ft at 500 ft/min requesting 15000 ft you are going to only clear the guy to 13000 ft until the above aircraft vacates 15000 ft?

Never mind getting my license suspended, if I controlled like that I would have never got a license in the first place.

Ok tough guy. You got a licence because you didn't follow the air law? I seriously doubt that.

What's your name and licence number? There are 30 days worth of strips, tapes, and radar recordings from your building that I bet Transport (and Nav Canada) would be very interested to examine for the times when you've been sitting in the position & breaking the law.

[the_professor]

I don't think I would ever use that visual separation stuff with 2 IFR aircraft. As for clearing an aircraft through the passing altitude of a faster climbing or descending aircraft, as much as it is safe it is not legal.

MANOPS 472.3 I believe, unless it's changed.

It's not visual separation; they're expected to report passing altitudes between each other on a discrete frequency.

[Braun]

Sorry I misinterpreted the "in contact with each other". Still sounds like a dumb way to do things to me.. I'd never use that, granted I don't have all that much altitude to work in either so it isn't really applicable!

[cyeg66]

So if you have a King Air 100, in a radar environment, at 14000 ft climbing at 500 ft/min to FL190 and a Caravan, or even another King Air 100, calls you climbing thru 5000 ft at 500 ft/min requesting 15000 ft you are going to only clear the guy to 13000 ft until the above aircraft vacates 15000 ft?

Precisely. I mean, I can't tell you how many times I've been 'had' by one of those JATO King Airs. EXCDS just doesn't have an appropriate place to display that vital info on which I'm basing my control actions. Name (I don't think parrot_head is your real name...) and licence #, son, let's have it... I've got the paper shredder warming up!

[cyeg66]

Sorry I misinterpreted the "in contact with each other". Still sounds like a dumb way to do things to me.. I'd never use that, granted I don't have all that much altitude to work in either so it isn't really applicable!

What's YWG capped at? If it's 17000', I see your point. You'd spend as much time setting it up as you would just streaming them and/or working rates of climb and laddering. Meh, thankfully the sky is big.

[burly]

What's your name and licence number? There are 30 days worth of strips, tapes, and radar recordings from your building that I bet Transport (and Nav Canada) would be very interested to examine for the times when you've been sitting in the position & breaking the law.

I think this is probably the lamest post i have read on this forum.


Why dont you hire a detective agency and find the guy. Im sure Transport would be so proud of you.