250kts below 10,000

[JRBarrett 3,073]

6 hours ago, Bluestar said:

Agreed.

Are you saying that if ATC restricts the aircraft to 250KIAS in the climb that the A/C does not have to comply? 🙂

 

The pilot can respond to such a request with a simple “unable”. Paragraph D of FAR 91.117 gives the pilot that authority.

It would be no different than if a controller instructed an aircraft with a VREF of 145 knots to slow to 120 knots on final.

Yes, a heavily loaded 747 could hold speed at 250 knots in climb if the pilot left the slats deployed and kept flaps at the 1 setting - but doing so is not “normal” procedure, which is what paragraph D addresses.

The point is that an experienced controller at a U.S. airport that handles 747 departures would never issue such a restriction. Experienced departure controllers are well aware that heavy aircraft such as the 747 have a minimum speed (with all slats and slats retracted) higher than 250 KIAS.

[scandinavian13 5,192]

4 hours ago, JRBarrett said:

The point is that an experienced controller at a U.S. airport that handles 747 departures would never issue such a restriction. Experienced departure controllers are well aware that heavy aircraft such as the 747 have a minimum speed (with all slats and slats retracted) higher than 250 KIAS.

Yeah, when I was doing some training to be a controller, I got asked:

"You've got a C172 that just went out and tower calls with an F-16 going out of the same field because an airshow ended earlier that day - how do you get them out without unnecessarily delaying the F-16?"

Answer: "Turn the 172 out of the way."

Done. Mischief managed...

Departure speed restrictions should really be an absolute last resort (as is backed up by the 7110, since it also limits restrictions to jets with a minimum of 230 - the 20 knot window is basically an allusion to "this shouldn't be done, don't do it").

[BlueStar 323]

6 hours ago, JRBarrett said:

experienced controller at a U.S. airport that handles 747 departures would never issue such a restriction.

Never, maybe. But I know for a fact if they can't their climb will be stopped or they will be turned. 🙂

Jim, I've enjoyed the conversation. Have a good day.

Grace and Peace.

[Guest]

Anyone know how the Concorde dealt with this restriction?  Assuming it was in place back then.

Cheers, Rob

[TopGun33 124]

It was already in effect. Speaking for French ops here :

They would not go supersonic before beeing over the Channel, so the first matter was to have Concorde as soon as possible at FL400 so they could fly above most trafic while remaining subsonic. They would give them direct to various SID VOR such as Évreux (EVX) as soon as possible and clear the path ahead so they could accelerate at convenience. The matter with Concorde was not really the first 10.000 cause that would be reached in a couple of minutes. The climb speed, even subsonic was unmatched.

[scandinavian13 5,192]

5 minutes ago, Rob Ainscough said:

Anyone know how the Concorde dealt with this restriction?  Assuming it was in place back then.

Just climbed on 250 til 10, and then I think it was 280 til transonic (and/or oceanic). It was pretty quick to climb that.

Getting out of JFK, you're out so quick and away from land that you're not restricted by much.

[Guest]

3 hours ago, scandinavian13 said:

Just climbed on 250 til 10

So this triggers yet another question, are there any restriction on rate-of-climb?  i.e. 250 KTS @ 8000ft/min ... I would think "rate" could be just a problematic as speed.

Cheers, Rob.

[downscc 1,327]

24 minutes ago, Rob Ainscough said:

So this triggers yet another question, are there any restriction on rate-of-climb?  i.e. 250 KTS @ 8000ft/min ... I would think "rate" could be just a problematic as speed.

Cheers, Rob.

I don't know why... as long as you are within your clearance.  If cleared to FL230 in climb that means you own the airspace ahead and above to FL230.... I picked that since odds are your climb to final will be through the lower and upper enroute sectors so the clearance is to the edge of the controlling sector.

[scandinavian13 5,192]

3 hours ago, Rob Ainscough said:

So this triggers yet another question, are there any restriction on rate-of-climb?  i.e. 250 KTS @ 8000ft/min ... I would think "rate" could be just a problematic as speed.

Nope. The only real rate instructions you'll hear are "best rate to ..." instructions. If there were a conflict, the controller would restrict to 1000 below until the crossing traffic were no longer a factor. Controllers work out expected performance well enough to see the type in the data tag and know how to handle it.

For example, if I had traffic ahead at 10000 that the Concorde might conflict with because of its rate of climb, I could turn it behind that traffic, or restrict it to 9000 until it's deconflicted and then clear it on up. My aim would be for the former, to avoid an unnecessary delay in the climb.

[skelsey 765]

3 hours ago, Rob Ainscough said:

So this triggers yet another question, are there any restriction on rate-of-climb?  i.e. 250 KTS @ 8000ft/min ... I would think "rate" could be just a problematic as speed.

Cheers, Rob.

ICAO does specific maximum and minimum rates of climb/descent, as it happens. The minimum is definitely +/-500fpm -- I'm not sure until I look it up but about 8000fpm rings a bell as a maximum. Don't know about the FAA (I know that the expectation in the US is that descent clearances imply an expectation of idle thrust, i.e. a decent rate).

Should add that the major consideration with high rates of climb (or descent) is that you may set off another aircraft's TCAS if you are hooning up/down towards them at a massive rate with the intention of levelling off 1,000ft below/above -- most operators (and some countries' AIPs) recommend or require that rate of climb/descent is reduced to c. 1000fpm in the last 1,000ft or so of the climb/descent to mitigate against this.

[Guest]

3 hours ago, downscc said:

If cleared to FL230 in climb that means you own the airspace ahead and above to FL230

But wouldn't that be cleared based on "expected" rate of climb and speed ... for example if aircraft X were at 6000 climbing (at 8000 ft/min) and cleared to FL330 on jetway A (and is ahead of another aircraft Y) with aircraft Y @ FL330 already on jetway A @ 500 Kts ... ATC controller thinking that aircraft Y @ FL330 has sufficient speed to pass aircraft X (below) before it reaches FL330 (aka aircraft X falling in behind aircraft Y at FL330).  BUT, due to the high rate of climb of aircraft X it ends up trying to share the same space as aircraft Y at FL330.  So I would think there would be some type of rate-of-climb restrictions?

It takes rate and speed to be able to project a point over time?

Cheers, Rob.

[Guest]

14 minutes ago, scandinavian13 said:

Controllers work out expected performance well enough to see the type in the data tag and know how to handle it.

That's what I would expect, but is there any "formal" written restriction on climb?  For example suppose their is a 1/2 full 737 Max relatively light on fuel and weather indicates a nasty storm cell within XYZ miles.  Pilot wants to get to high altitude ASAP to fly above the storm cell ... toss out all the company requirements and decides on a 8000ft/min climb to FL330 ... ATC controller was not expecting such a rate of climb.  I realize this is probably very unlikely situations but after listening to several active RW pilots on YouTube and other mediums there appears to be considerably different set of "company" rules (certainly outside of the US).

Cheers, Rob.

[scandinavian13 5,192]

4 minutes ago, Rob Ainscough said:

So I would think there would be some type of rate-of-climb restrictions?

Again, if you had hesitations, you just wouldn't clear them up to that limit. If you're having to restrict V/S, you're not doing it right, honestly.

Additionally, the data tags don't show rate (State-side). They just show actual, assigned and/or temp (depending on the control display), and a climb/descent indicator (depending on the control display). As such, you really don't get a rate to judge things off of (and related to my above point, it's really of no concern). Controllers get a feel for aircraft performance just as a pilot would. A departure controller working MEM departures knows that the DC-10s, MD-10s, MD-11s and 777s heading on long hauls are going to be a bit sluggish in the climb; whereas the controller working the early morning UAL 777 transcon departure out of SFO to IAD knows it'll be a bit peppier.

In your scenario, if the controller were worried, they'd issue FL310, or even FL320 (traffic and airway-dependent - single direction airways exist, much like NATs in certain areas).

Just now, Rob Ainscough said:

That's what I would expect, but is there any "formal" written restriction on climb?  For example suppose their is a 1/2 full 737 Max relatively light on fuel and weather indicates a nasty storm cell within XYZ miles.  Pilot wants to get to high altitude ASAP to fly above the storm cell ... toss out all the company requirements and decides on a 8000ft/min climb to FL330 ... ATC controller was not expecting such a rate of climb.  I realize this is probably very unlikely situations but after listening to several active RW pilots on YouTube and other mediums there appears to be considerably different set of "company" rules (certainly outside of the US).

To be honest - having worked with a lot of the airlines in the arena of collaborative decision making, there were a handful of airlines that got it right simply by actually regularly discussing ops with their local facilities, and there were airlines who just didn't care. Guess which ones had all kinds of weird assumption-based stuff in their SOPs...

If you're at the console, and working competently, you don't clear anything that would get close enough for rate to matter. If you've got traffic above the hypothetical super-performer and you're worried they'll conflict, you limit the altitude you clear them to. If one guy is cruising at FL320, you clear the climber to FL300, and then once deconflicted, step the climber to whatever higher they wanted. If one is descending, and you have the super performer climbing, you limit one or both, tactically.

...it comes down to a good scan. It's surprisingly easy to pick up on.

 

I'll put it this way:

You've got a guy ready to take off, and a guy who needs to cross the runway the first guy is about to take off on. Do you clear both and tell the pilot taking off to de-rate takeoff so the roll is longer/slower, or do you limit one/both (Pilot A: cleared for takeoff; Pilot B: hold short ; Pilot A: line up and wait, traffic crosses prior to your departure; Pilot B: cross Runway X at Y)?

[BlueStar 323]

1 hour ago, scandinavian13 said:

 Again, if you had hesitations, you just wouldn't clear them up to that limit. If you're having to restrict V/S, you're not doing it right, honestly.

Kyle,

In the AIM 4-4-10-d  (page 4-4-6) it talks about what is expected as to rate of climb or descent.  

" Descend or climb at an optimum rate consistent with the operating characteristics of the aircraft to 1,000 feet above or below the assigned altitude, and then attempt to descend or climb at a rate of between 500 and 1,500 fpm until the assigned altitude is reached "

Hope this helps.  🙂

 

Edited September 26, 2018 by Bluestar

[scandinavian13 5,192]

12 hours ago, Bluestar said:

In the AIM 4-4-10-d  (page 4-4-6) it talks about what is expected as to rate of climb or descent.  

" Descend or climb at an optimum rate consistent with the operating characteristics of the aircraft to 1,000 feet above or below the assigned altitude, and then attempt to descend or climb at a rate of between 500 and 1,500 fpm until the assigned altitude is reached "

Hope this helps.  🙂

I'd argue that what we've been discussing fits in with that definition. Granted, the light-737 climb example might be on the 'high' end of the "optimum" and "consistent [with the type]," but Concorde climbing like Concorde, at OPT, and consistent with type fits right in.