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Standard speed during descent

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Standard speed during descent

Old 16th Jul 2012, 09:33
  #21 (permalink)  
 
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I missed the "TP" bit.

I wouldn't ever expect you to do 270kts in, say a DHC8-expect to be moved to one side as you suggest.
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Old 22nd Jul 2012, 20:07
  #22 (permalink)  
 
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I read something very good in a 1968 737 operations manual recently. It said to plan 320 KTS for the climb and 320 or 350 KTS for descent! Easily know the price of fuel was so cheap back then. I find taht 300 KTS works fairly good in the London TMA. Our ECON descent is 273 KTS which is way to slow, but when I hear jets cruising at 0.74 and then descending at 240 KTS, that's just not right.

High speed all the way
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Old 23rd Jul 2012, 16:30
  #23 (permalink)  
 
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I find taht 300 KTS works fairly good in the London TMA. Our ECON descent is 273 KTS which is way to slow, but when I hear jets cruising at 0.74 and then descending at 240 KTS, that's just not right.

High speed all the way
The problem is that almost no one else seems to be going at 300kts anymore as it just so inefficient fuel burn wise. Why is 273kts too slow? Many other operators are saying they want around 250kts or even less at the moment and some as slow as 230kts especially at night when the traffic allows.
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Old 23rd Jul 2012, 20:54
  #24 (permalink)  
 
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Why not just let the aircraft fly the speed that they want. After all, they pay the fuel bill and if their Company wish to exercise control re. fuel burn then that is their business. ATC seem to be interfering far to much with the speed that aircraft fly at with only scant knowledge of what is or isn't an appropriate speed and then after lots of vectoring all over the sky ending up in one of the TMA holds for 15 minutes. Tell the plane how long the likely holding is as early as possible and then let the pilots work out their best speed to try to achieve minimum holding.
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Old 24th Jul 2012, 06:14
  #25 (permalink)  
 
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... and how does that help achieve separation against the one behind who fancies going a little faster?
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Old 24th Jul 2012, 08:22
  #26 (permalink)  
 
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I think that you might use that age old bit of ATC magic called 'radar' and the time honoured 'radar heading' to solve that irksome problem.
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Old 24th Jul 2012, 11:00
  #27 (permalink)  
 
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Oh of course, why didn't I think of that. Except of course where the sector length involved, as is often the case, is just enough to end up with 2 aircraft abeam each other instead of nicely in trail, overtaken or not. Still, I'm sure the next sector will sort it out....
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Old 24th Jul 2012, 11:19
  #28 (permalink)  
 
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As always.
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Old 24th Jul 2012, 15:35
  #29 (permalink)  
 
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one aircraft from an Irish based airline which operates many 737s was descending from the cruise to around FL200 at 330kts the other day!

If there's no delay, 270-290kts seems to be the norm (unless you're a turboprop!). If I'm not too busy I'll normally ask No 1 in the stream what they're planning on converting to. Anything over about 15mins delay and I'm slowing people back to 250- kts .

Even with Mode S there are still a few pilots trying their luck flying a different speed to what I've given them. So frustrating - you're on a speed for a reason.
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Old 24th Jul 2012, 18:02
  #30 (permalink)  
 
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You can tell how late a flight is by the speed they select. Paris CDG to Heathrow is such a route where the competing airlines that fly it will cruise between 240kts and 340kts without saying anything. Likewise a certain German carrier will climb at 340kts almost without fail. Telling an aircraft it has 15+ minutes delay still doesn't mean they can slow right down, some routes have level restrictions that must be met and can be impossible at the optimum speed so 280kts+ may be necessary.

But obviously we have hundreds of miles of free airspace so I can just use vectors to avoid all the other aircraft flying the same route at different speeds, taking into account avoiding other FIRs, sectors and military training areas. Such a simple job I am surprised they haven't trained monkeys to do it yet....

And don't even start on "radar heading"!!
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Old 24th Jul 2012, 19:01
  #31 (permalink)  
 
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Why not just let the aircraft fly the speed that they want. After all, they pay the fuel bill and if their Company wish to exercise control re. fuel burn then that is their business. ATC seem to be interfering far to much with the speed that aircraft fly at with only scant knowledge of what is or isn't an appropriate speed and then after lots of vectoring all over the sky ending up in one of the TMA holds for 15 minutes. Tell the plane how long the likely holding is as early as possible and then let the pilots work out their best speed to try to achieve minimum holding.
Spoken like a true office jockey that's never seen the inside of an ops room or at least has no concept of how the job is done

Last edited by The Many Tentacles; 24th Jul 2012 at 19:01.
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Old 24th Jul 2012, 21:35
  #32 (permalink)  
 
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Er,no.Middles is one of the most experienced Atcos,both en route and TMA,plus time enjoying Dining In nights as one of Her Maj's boys in blue.
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Old 25th Jul 2012, 11:04
  #33 (permalink)  
 
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one aircraft from an Irish based airline which operates many 737s was descending from the cruise to around FL200 at 330kts the other day!
LOL! It can do 340

You make it sound like it was a crime....
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Old 26th Jul 2012, 08:21
  #34 (permalink)  
 
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Telling an aircraft it has 15+ minutes delay still doesn't mean they can slow right down, some routes have level restrictions that must be met and can be impossible at the optimum speed so 280kts+ may be necessary.
But also many of the "level by" points are not about separation but were established years ago because crews were not managing their STAR descent profiles properly and were often unable to achieve the standard speed and min stack. On most of the sectors this is the case and if there is significant holding then it is less likely that they need to make all of the standard levels.

I find using a phrase "expect FL150 at XXX reduce to minimum speed to achieve that" usually works.
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Old 26th Jul 2012, 08:46
  #35 (permalink)  
 
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I use that phrase all too often now 250kts. Most of the tight SA's on my sectors are used for separation too so quite crucial to meet them. Sadly getting the arrivals in at lower levels is only possible for short spells no longer than 30 minutes, something that is in the pipeline to be sorted, but its been stuck in the pipe for over 20 years!! Wonder who that will be then........
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Old 26th Jul 2012, 17:18
  #36 (permalink)  
 
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LOL! It can do 340

You make it sound like it was a crime....
It's not but I would plan on 270ish being a more realistic outcome
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