Virgin on a go slow?

[Going Nowhere]

Same theory seems to work on the Q400.

Fly at Max Cruise (MCR) = less holding into BN/SY/ML.
Fly at Intermediate Speed Cruise (ISC) = 5-10 mins holding + 5-10mins lost in the cruise.

But still flying slow saves fuel, doesn't it?

Sure does until you start holding!

[porch monkey]

Dns, it's the actual speed that is the issue, not necessarily the C.I. Each airlines speeds are derived from their particular C.I, and they won't necessarily be the same speed, even if same a/c at same level etc. The speed the C.I generates for the a/c varies with the inputs made by the airline with regard to fuel, maintenance, lease, crewing, and any other **** they dream up. It all goes into the formula, and spits out an answer. Change any of the variables and you get a different speed. What you need the companies to provide is the actual tas. Which you get, I believe. As far as telling the bean counters how to run things, well, you know how that goes. We see the result of their meddling, complain, but often zero happens. Couple of months of this **** will give an easily definable pattern for them to quietly drop it as the stupid idea it may be. If you want to know how much input flight ops often has, ask yourself who's idea buying ejits was!

[Capt Claret]

If you are going to fly at such ridiculous speeds why don't you excercise some airmanship and tell someone.

Until reading this thread I would have made the reasonable assumption that if one's flight plan indicated a cruising Mach of 0.62, then one HAD advised ATS.

If this is not that case, why put the cruise speed in the flight plan?

[willadvise]

I know it's slightly different but I've been meaning to ask - when ATC says "Hold at XXX, expect to depart XXX at XXXX, speed reduction approved.", is there any limits to the speed reduction?
Heard some ATC cracking it the other day because a 737 slowed down to 215KIAS and "that if you are going to slow down that much you have to let us know." Huh? Since when?

grrowler.
In this situation I think the controller should have been more careful. Once I slow an aircraft down like this I will either ask them what the are going to reduce to or descend them to avoid any following traffic because I am amazeded at how slow you can go sometimes. In saying that if you are aware there is an aircraft behind you, a call saying that you are reducing to x kts/mach can't hurt.

I'm very out of date here, but, from memory ....

Companies have Letters of Agreement with Airservices detailing a lot of stuff, including performance figures.
ATCs are trained in line with those agreements.
If the general performance figures are changed, the Company is expected to update the Letter of Agreement
Speeds entered into the flight plan are not entered into the software that ATC use???? I think.

So, obviously ATCs are expecting certain speeds. When they don't happen ...

Peuce et al
MATS currently details maximum cruise speeds for each company aircraft type and typical/maximum/minimum speed for approach and climb. There is no agreement for cruise speeds and the approach speeds are not mandated.
Speed entered into the flight plan is entered into TAAATS and estimates are calculated using the information.
The difficulty is 2 fold
1) Some enroute sectors operate with TMA strips which don't show the planned cruising speed and hence can't change the speed if a pilot advise them of a change. The only way for these sectors to see you planned speed is to open the flight plan window and check it which is time consuming for the short haul radar sectors.
2) There is a huge variety in flight planning accuracy and compliance with flight plan speeds. You soon learn that what is flight planned is not flown 50% of the time. There are any number of reasons for this eg schedule, wind different to forecast, use of a standard plan which is not updated to reflect current conditions, pilots not knowing what speed they have planned (or had planned for them) etc. Some operators will plan a change of speed with a change of level which is not requested. Some operators will plan a level and approach speed at a waypoint near the aerodrome, some will plan a climbing speed on departure which doesn't reflect cruising speed. All of which has ATC's very sceptical about planned cruise speeds. The upshot of all this is that if I am going to run you close together I will ask your speeds everytime even same type and same company. Gone are the days of you could rely on the plan or typical cruise speeds.

A comment on low and slow. If you are in a 73 and have planned F240 .64 I am likely to think you have a pressurisation or engine problem that precludes operating at normal speeds/levels.

As for sequencing you sometimes will end up with the rough end of the pineapple but I have seen it the other way. Ie I have watched someone flog it the whole way across the bight vs someone taking it easy. The first aircraft copped 15 mins delay due traffic, undoing anything time he made up and the second was naturally at the end of the sequence and had no delay.

[porch monkey]

Willadvise, you've said it in less words and simpler than I could. As for the low/slow, I certainly haven't had one of these plans recently, but the econ speed for FL240, would be about .63 or.64 I guess, given the C.I we're using. No a/c problem, just the way the box works. With the cost index we are using at present, fuel burn is the highest priority, and the plane will burn about the same per hour at that speed/level as it does at .78/FL380. Don't get me started on the sector lengths! (Which of course for the smartest men in the room MAY actually increase overall burn!) Occasionally used to alleviate high winds, which is my suspicion at the moment. Guess I'll find out when I get back to work!

[nitpicker330]

Porch Monkey…………

the plane will burn about the same per hour at that speed/level as it does at .78/FL380

Your Fuel Flow may be the same BUT your TAS will be quite a lot slower and thus the kg/gnm will be a lot worse.

Obviously the aim is to achieve the best kg/gnm, which FL that is at will depend on wind gradient.

It's all down to fuel flow/GS calculations.

Sorry, im not trying to teach you how to suck eggs!! I suspect we are all on the same page.

[Captain Peacock]

As for sequencing you sometimes will end up with the rough end of the pineapple but I have seen it the other way. Ie I have watched someone flog it the whole way across the bight vs someone taking it easy. The first aircraft copped 15 mins delay due traffic, undoing anything time he made up and the second was naturally at the end of the sequence and had no delay.

tee hee, been there, done that. I've learnt the hard way, never 2nd or 3rd guess cos you will invariably be wrong! (Just ask my wife)

[porch monkey]

Yes we are Nitpicker, that was my reference to the sector times. (more time spent burning the same fuel flow!) As a wind alleviator it's ok, and we use it occasionally, (usually at higher speeds and always with ATC's knowledge!), but I have checked and can find no reference to any specific directions at this stage. Of course, as I said earlier, we're usually the last to know.......

P.S. I mentioned the same fuel burn at differing speeds and levels, as it APPEARS the same, we know it isn't but our learned friends with MBA's, (You know the ones, AKA smartest guys in the room) probably don't.

[TwoFiftyBelowTen]

I am en-route Brisbane and have quite a bit to do with this lately. The only real problems are caused by aircraft not flying at the speed the company has filed them with. I am frequently checking this now, and frequently finding enormous variation (despite being told by some crews that the company has told them to fly at the speed stipulated). I asked if it depended on whether or not the flight was running to schedule but apparently not a determining factor. One Virgin B737 plan will list a TAS of 450 and another will have 375. Even at the same level. MAESTRO allocates landing times based on the cruise TAS planned. If you go fast it will not reposition you earlier, it will just insist that you are running ahead of time and you need to be delayed to achieve your time. (It's French, after all!). ATCs need to be aware that changing the TAS in the "overall" cruise TAS field of the FDR will be overridden if route segments have any level changes and a different TAS stipulated for those route segments. (I just realised/remembered this recently!)

[Jack Ranga]

Until reading this thread I would have made the reasonable assumption that if one's flight plan indicated a cruising Mach of 0.62, then one HAD advised ATS.

Your mach number is not stipulated in the flight plan, only your TAS.

As I said, your friendly ATC will not be checking every flight plan, simply not enough time (at times) and impractical.

[Angus McGherkinsquirter]

JR, DNS

I flew over to MEL from ADL yesterday morning. Might as well have been at .62. Planned .78, flew .78 50kt tailwind, and 19 mnutes from ML we were given 20 minutes holding. When asked how long the delay had been apparent, the ATC replied 10 minutes. Would have been nice to know earlier to slow down n save some gas, surely this communication thing has to be both ways.

[framer]

And I just flew into ML tonight, got given a fix time that required us to speed up, a few minutes later, back to normal speeds thanks, a few mins later, best speed cancel speed restrictions, onto approach and told to slow down....geeeez wayne.... I'm not havin a go at any front line ATCers but when combined with the 1970's style approaches onto 34 it makes me wanna stay away from Ausi.
To some of you experienced controllers, if you were the head honcho for five years, of all ausi atc...what would you do to make things run smoothly?

[Jack Ranga]

Squirter,

Maestro is a piece of ****, it really is. It looks out approximately 160 nm. It, like any piece of software has its limitations one of them being the operator or the manipulator! It still requires a person to oversee/monitor and manipulate it. Prior to maestro we had a flow controller working out the order and speeds etc. So why buy it? I don't know. Maybe it's another manifestation of the spin bull**** that ASA continually feeds industry?

As an example we have just gone to what's called 'voiceless co-ordination' it's one of the things that TAAATS was built for, only taken us 10 years to implement and now TAAATS needs replacing. There ya go!

If you go through my airspace you won't be getting your flow time at the last minute. (a lot of ATC's do this because the fix time changes that many times, you sound like a complete cockhead changing it all the time). I'll set your time, give you the fix time and then un-fortunately we'll run with the changes.

Add to this, I just don't effing know what speed you blokes are doing anymore that it just takes one of you to do things a little differently and it completely shafts the sequence.

Framer,

Have a look at the financial statements that ASA publish, back office numbers have exploded whilst ATC numbers continue to dwindle. ASA are famous for the 'little' empires that are built from time to time. There are two now, 'PR' or the spin department and 'People & Change' P&C wouldn't know their arse was on fire until they got their finger burnt.

The best example of these imbeciles:

ATC mate of mine goes overseas on a contract, comes back to Australia, gets a job in the 'Learning Academy' teaching ATC. Wants to get back on the console controlling. These f@#kwits in Canberra are making him go through the whole application process to see if he is 'suitable' for ATC?

He says to them: 'You do realise that I'm teaching ATC in the college?' He gets the standard response from some ******** HR degree graduate (the degree you do when you fail Arts).

How are you suitable to teach ATC in the college but not practice in the field?

Rome burns! ASA will be losing up to 80 ATC's a year (boomers retiring) and the college can train a maximum of 40 per year.

ASA needs a serious cleanout. I bull**** you not, I could fix it in 18 months. We all know what's wrong in this place, it's a yes man's paradise. The top dog doesn't want to know what's wrong and the 'ATC hate cell' in Canberra have control.

[porch monkey]

Hey Jack, it's somewhat comforting to know that both sides of the aviation equation have similar kinds of f@ckwits to deal with. You have my sympathies.......

[HF3000]

To the best of my knowledge, we don't provide ATC with a TAS, we provide them a FL and a Mach Number. Maybe your system converts that to a TAS by the time you see it, and if it does there's the start of the problem.

My airline (QF) has standard descent speeds - for most fleets it is 280kt. We are told that ATC knows that. I have never witnessed a fellow crew member intentionally descending at a speed other than 280kt unless requested or authorised by ATC, so I don't understand the comment that you never know what speed we are doing.

And why is it so difficult to just request a certain speed from an aircraft if that will make your job easier? They do it in many busy airports elsewhere in the world. Sydney does it sometimes, I've been asked "make your descent speed 280kt" several times... I don't understand why, according to Qantas you have been advised that 280kt IS our descent speed unless authorised otherwise.

[TwoFiftyBelowTen]

I think you have latitude for +/- 10 kt. If we don't want the possibility of you doing 290kt we specify 280kt

[HF3000]

Yes we have latitude for +/- 10 kt in the standard descent profile. That is for small speed variations during descent. However, ATC specifying 280kt still does not change the latitude of +/- 10 kt, so the outcome is no different.

[TwoFiftyBelowTen]

.... and you are correct, HF3000. Your cruise speed lodged as Mach is converted to a TAS in our system for the level and forecast temperature at that level you plan. We can however then interact with it and put it in as Mach, ... so I don't really know why it starts off expressing it as TAS.
And,... when your B767 heads off to Perth climbing to FL380 and requests amended FL260, the TAS field stays the same unless we manually change it. TAAATS calculations for entry/exit to lateral conflict points and time-of-passing etc might possibly be in considerable error unless that TAS field on the FDR is corrected for the new level

[HF3000]

And,... when your B767 heads off to Perth climbing to FL380 and requests amended FL260, the TAS field stays the same unless we manually change it.

And that, like I said, is the start of the problem. What a ridiculous system... Obviously programmed by someone with no idea of high altitude aircraft performance.

Your system should have the ability to generate a TAS based on the level the aircraft is AT, not based on the level the aircraft is planned! So simple, and so stupid they didn't program it that way.

So I hope we have debunked the blame from pilots who most of the time do cruise at their planned Mach no, it is the ATC system that incorrectly reports planned TAS when pilots cruise at other than their planned level, which of course they do regularly due winds turbulence etc.

[framer]

its a systemic problem. Not ATC's, not the pilots.

Told ya that back at post 27!!!