Descent speed
 

Hi all,
sitting out by the fence with my scanner last week, I have noticed that QF seem to be flying slower descents above 10,000ft than they used to. Does anybody know why?

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FMC equipped aircraft have a function known as "cost index". It is a function of fuel costs vs other hour variable costs and allows the FMC to calculate the most economical speeds for climb, cruise and descent. As fuel cost's rise, so the economy of operation is biased more towards fuel conservation (and thus slower speeds).

I dare say Qantas has re-calculated its' cost indicies and this has resulted in slower speeds.

I know in my operation we are operating with a signifigantly lower cost index (i.e. higher fuel costs) than a year ago, and this has resulted in climb and descent speeds around 10-15kts slower, and operating Mach numbers .01-.03 less.

Gotta love those A-Rabs!!

But Wiz, does it pay off? Now you are number two even when you are in front; which may mean more time in the air; thus more fuel burnt.

Spot on Wizofoz.

New QF Descent procedure have just come into effect.

Yawn, freeking yawn. Another new broom trying to re-invent the wheel. :rolleyes:
Where have these geniuses been hiding until now? :rolleyes:

Bye!

:ok:

Woomera

Kornholeo,

An observation one may make with such well versed and articulated prose.

One may draw a conclusion as to how one could manage to be in a position of being banned on a regular basis with ones "Beavis and Butt-head" reincarnations and impolite mantra.

As I said, just an observation, not a personal attack.

:rolleyes:

When you consider the small amount of fuel used on a descent to try to save an egg cupfull by reducing speed is futile. You'll save 3/5ths of 5/8ths of f*ck all.

The real savings are in the cruise and climb. But some aces try to reinvent the laws of physics every day. Yawn.

What happened to standard descent profiles to appease ATC ?

Thought this was standard to assist ATC with planning and sequencing ?

Standard descent profiles in the red jets.

Just found it fascinating a few days back to see QF speed along all the way from Perth, pass us, only to slow to "276 econ. profile sir" on the way down. I doubt whether fuel saving is the reason.
Im not having a dig, just feel as though Im missing a little more than usual.

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The QF FOQA (flight operations quality assurance) program on the 737 fleet identified a huge amount of unstable approaches and have introduced 210kts @ 5000'!! There Cost Index has nothing to do with it. If it did, then they would be cruising around at 41000' with us. On the descent page in the FMC, we modify the descent speed from eg M078/300kt then 250kt/10000'. Typically, if we get max cruise cancel STAR speed restrictions we modify the above speed to M080/320kts and delete the ATC 250kt restriction below 10000'. QF just use there econ descent which is a right royal pain in the arse to everyone in the airspace. :( What a bunch of w@nkers!!!

iTS ACTUALLY 250KTS by 5000, and 210kts by 3000.


The descent speeds now based on Cost index and econ are a management implementation, not the pilots. Dont blame them.

Level change, it is a bit harsh calling them wankers!

The QF pilots, in exactly the same way we are, are governed by those that makes the rules in their organisation.

They, unless they wish to be non standard, are forced to operate in accordance with their SOP's, like 'em or not.

I reckon if you ask them as individuals they would have an opinion about the speed control issue - and it wouldn't be favourable!

The management of each company has to react to the situations that they find themselves in - if an aeroplane crashed and people were killed because of an unstable approach, the lawyers would crucify the pilot management for NOT imposing restrictions such as they have done.

The 210 kts is fine, if you hit 3,000' around 10 - 15 track miles to run. Is there any freedom given to pilots to adjust the 210 if you are forced or need to get down to 3,000', earlier than usual?

As for 250 by 5, that's almost laughable - but highly fuel and aircraft INefficient.
The "norm" used to be 5,000' - 300kts - 20 miles to run.

Another "dumbing down" and cost INCREASING initiative.
They're bl@@dy jets you're flying - not Cessna 150's!

So remember, if you get your STAR cancelled, or slowed, or vectored all over the sky when you are only 40 MTR, you already know the answer why - so don't bother asking the question!

BTW, that highly refined piece of engineering called MAESTRO which the airlines got told will solve their woes, will NOT take in to account aircraft flying different profiles - see previous answer above.

As usual the golden rule applies:" ATC don't delay aircraft - other aircraft delay aircraft".

Solution? Build some more runways - good luck getting it past the NIMBY's. (I hear even Tyabb is getting noise comlaints now!)

Level Change 340kt,

Would you mind pulling your head in, line pilots don't set policy just follow it unless it's dangerous.

I don't agree with how we are being instructed to fly and do not feel we have any voice but rather are being dictated to by office pilots who are luck to fly once a month. It's embarrassing enough having to fly like a lemon without your insults.
With luck this 'trial' will not last long, in reality though I fear it may be here to stay.

And the CP wonders why we are not engaged......:ugh: :\ :yuk:

Don't be too concerned about the sky falling coz Qantas goes a bit slow, just makes them look more like the internationals. Now VOZ closes on QFA on descent & QFA closes on VOZ on climb. Easy-peasy!

Maestro copes, just change all QFA estimates minus one minute, and what they lose on the swings they will pick up on the roundabouts.

US... I beg to differ.

I was coming back from Perth to SYD not too long ago and we over-ran the VB 737 out of ADL prior to Wagga. Didn't make any difference to ATC. They gave VB direct to Rivet even though he was 10 miles behind at this point, and us a 90 degree right turn for "speed management". Then we we got closer we were told to speed up and cut inside the star.

Still makes me shake my head.

We're still doing 250 below 10 Kornholeo. Just like everyone else. The slower descent speeds apply above 10 000ft.

Yes there is. It's 210 kts below 3000ft. So you can fly 250 kts at 3000ft if you wish. Handy when PRM approaches are being conducted.

Standard descent profiles are agreed to between Airservices and the "customer" - in this case Qantas. The speeds aren't necessarily ECON, but 275 kts +/- 10 kts. Qantas tells Airservices the speeds which will be flown, and the data is incorporated into Maestro. So it has little effect on other operators.

And Level Change 340kt you're my hero. Until a few days I used to descend at M0.80/300 kts too. Really difficult isn't it:rolleyes: :rolleyes: ?? The decision had no input from line drivers. We just follow company instructions. Get over yourself . . :mad:

Cutest of Borg,

Don't know the answer because I don't know SY. I can imagine plenty of scenarios where this would happen however - e.g. is the reason you flew past VB because it had already been slowed en-route to cross the feeder fix in to SY?

Honestly, if you call up (soon after landing so someone might remember - we work in data-dump mode continuously) just ask how you came to be after - I am not saying complain, but there may well be a reason you are not aware of that may well put your mind at rest.

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