Expecite

[caucatc]

What rate of descend/climb can be called "expedite" ? Is there any rule for that ? When I said "expedite" ,the pilots idea about that are much different.

[Rule3]

Answers.
1. 300fpm to 6000+ fpm :(
2. No :confused:
3. Correct.:ok:
Grossly overused instruction that means :mad: nothing.

[zkdli]

Taken from the UK MATS PT1 (CAP493)

Expedite climb/descent.
To require a pilot to climb/descend at best rate. Within controlled
airspace pilots have been informed that this rate should not be
greater than 8,000 ft per minute.

:O

[anotherthing]

Rule3


Grossly overused instruction that means http://static.pprune.org/images/smilies/censored.gif nothing.
disagree with you there I'm afraid, at least if the ATCO is any way half capable.

A/C will climb at the best rate for them - i.e. a balance between climb performance and economy.

ATCO climbs A/C to a safe seperated level from conflicting traffic and monitors the climb rate, bearing in mind the statement above.

ATCO, using judgement and experience (it's what we are paid for after all), decides that a climb through will work at the current or slightly better rate than is being shown at the moment.

ATCO instucts the A/C to climb, using expedite through a few critical thousand feet to ensure that the situation works. The word expedite means forget economy, give me performance. It should be used for a level band of a few thousand feet, not for tens of thousands.

Not a useless technique, but one used in busy airspace everyday - though used sensibly when the situation dictates.

An extremely valid technique and instruction which if used in the correct instances, will help greatly reduce ATCO and sector workload/complexity.

CAUCATC

As rule3 correctly states in his first answwer to you, the ROC could be anything - it depends on the aircraft characteristics etc.

As an ATCO, you are paid to use your judgement, as I have explained above.

If you are in a situation where you want a specific minimum ROC to ensure that a situation will work, then you can ask the pilot if they are able to give you that rate or you can specify it in the instruction - the pilot must tell you if they cannot comply with the climb rate if you use the latter technique - and as it is part of (a condition of) the clearance, they must tell you so without starting the climb through.

ZKDLI

That reference you have given is amusing - it states 'must climb/descend at best rate', but it does not state that by best rate it means best climb/descent rate... a best rate for a pilot could be the most economical one, though in the context of the definition, you would hope that the pilot understood that in this circumstance, 'best rate' related to best ROD/ROC!!

[TopBunk]

[as a joke] what exactly would expedite climb result in in a heavy A340-300 - as I understand it with them you can either climb OR accelerate;)

[anotherthing]

TopBunk

the very reason I would not use expedite for an A340!!

The A380 however...

[Rule3]

Top Bunk, :hmm: I answered the question as it was written.:\ Best rate of climb [and what will it be] till out of FL... is a far more positive instruction as I see it, as all sytems managers, :(aka pilots, operate differently. I have witnessed this in BUSY AIRSPACE for several years with a variety of different types and airlines having their own SOPs.:ok:

[TopBunk]

R3

I have operated B737-2/3/4, B747-4, A319/20/21 which all perform reasonably (although differently, as a function of weight, of course).

My jibe was that the A340-2/3 is legendary in its inabilities to:

1. Climb and accelerate
2. Maintain reasonable airspeed in the cruise (slowing everyone else down for hours)

whilst

1. being able to climb at an early stage to a high level (albeit slowly) due to an excellent British wing, thus depriving and frustrating faster aircraft for many hours at a time.

Dog (of the female persausion) at its best:hmm:, imho

[ron83]

light 767 good time to ask to expedite:E

[Pure Pursuit]

I've used 'expedite climb' several times in order to get some F15s or Typhoons above civil traffic in order to stay out of the way during a transit.

The ROCD limitations that are in place are not ideal however & restrict the a/c to 8000ft min -+.

Should I wish him to exceed that limit, I simply have to say 'Expedite climb, no restrictions' & any self respecting Typhoon pilot will point the nose at the moon. Once he is level, I'll reapply the ROCD restriction, allowing me to take Charlie Sep against traffic beneath (saves calling an often busy Tyne/Humber sector controller).

I appreciate that the idea is based upon Mode C dropping off the scope & having an impact on TCAS however, I do not see the point of having it if, having coordinated 2k below civil traffic in CAS using the phrase "Not above FLxxx no restrictions for coordination", the Typhoon in question can then climb towards that traffic with an unrestricted ROCD, just as long as he does not break coordination. Civil traffic will get a TCAS RA & climb & the controller will still file on me! Barking.

The fact that we can lift the restriction whenever we see fit does make me wonder as to whether we should bother with it or not. Either restrict ROCD in CAS at all times or, bin the idea.

What say the civil sector? I'm genuinely interested as this subject is causing no end of debate in the ASACS world.

[zkdli]

Pure Pursiut
The rate of climb/descent limitation came about because of a loss of separation in 2006. A B747 lost separation with a Jaguar that was making a zoom climb departure from an Airdisplay. (I know... a jaguar:))

In the incident, the primary and the secondary returns were lost because the radar processor decided that the climb rate was such that it could not be an aircraft.
The controller of the B747 only saw the conflict as the Jaguar was descending from the climb. It had lost separation on the way up and on the way down. The aircraft TCAS did not "see" the conflict and I beleive it was simulated to be outside of the parameters of the aircraft performance to be able to avoid the conflict.

I have seen enough level busts by high performance military aircraft to know that the climb rate is barely acceptable for keeping it safe in CAS. Relying on TCAS in this situation is not a really good idea when the perfomance of the mil aircaft far exceeds the available performance of the civil aircraft to avoid it.

[Pure Pursuit]

zkdli,

I believe it was a GR7 that caused the issue. A Jag pilot could only dream of a high ROC!!!;)

Looking at the civil atc side of the issue, I can see why the rocd restriction has been pushed for. TCAS must never be used as a separation tool & in order to make sure Mode C is always available, perhaps we should only release the ROCD restriction inside the MDAs? It would have an impact on overland training however, safety must come first.

[1985]

Pure Pursuit

On the civil side we have to file on TCAS RA as its a MOR. We can't not as the pilot will.

Have to say though that letting a Typhoon point his nose at civil traffic and then saying unrestricted climb is a bit silly.

[Pure Pursuit]

1985, that's not how it works.

We coord 2k above/beneath the GAT traffic, add 'no restrictions' as a suffix to the format and the ROCD is unrestricted.

My point is that someone decided (quite rightly) that ROCD could cause Mode C issues. What I'm struggling to understand is the caveat that allows us to do this. Most ASACS controllers will only release the ROCD if there is no factor GAT traffic however, the option is still there & many of us are finding it rather amusing that somebody thought that it would be acceptable to civil ATC.:ugh:

[Northbeach]

Caucate,

I fly the NG 737 and previous to the 737 a variety of corporate twin engine jets so that is my background. I can’t speak for the military pilots or those flying the 757 or aircraft with 4 engines.
When you tell me to expedite and I am below FL180 there are a lot of options available to me. I can trade altitude for airspeed, giving you a lot of altitude gained quickly at the cost of airspeed. However at the higher altitudes mid 30s & above and heavier weights I really don’t have much to offer you.
The FMC (Flight Management Computer) gives me the ability to climb at best rate, most altitude gained over a given time, or best angle the most altitude gained over a given distance but in reality neither of them are a stellar performance when I am at the heavier weights, higher altitudes or the flight environment is significantly warmer than ISA.
At higher altitudes and heavier weights the airspeed spread between low speed buffet and overspeed becomes fairly small-20 knots or less. If I get too slow the aircraft will begin the stall sequence and I may not have the power to accelerate out without giving up altitude. Fly too fast and I am exceeding a manufacturer/company/regulatory authority limitation. I must keep the airspeed between those limiting airspeeds. My engines are putting out all they have to give. In a lot of cases I just don’t have much to offer you. There is certainly no regulation that specifies a rate of climb that I am required to provide when you request an expedited climb, it is not a lack of cooperation on my part, rather it is a lack of excessive performance to offer.

Respectfully,