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Check Airman
10th Sep 2007, 16:10
Hey all,

For all those in the know, I've got a question that's been bugging me. In a Boeing, you can select reduced power for the climb phase (CLB1 or CLB2) in pretty much the same way you select reduced power for takeoff (TO1 or TO2). Now I know that the bus can do FLEX takeoff's, but can you also reduce thrust in the climb, or do you always have to use full power? Or does the FMGS do all the work as directed by the CI?



Thanks for all replies

westinghouse
10th Sep 2007, 17:00
hey,

the A330/A340's have the derate climb function ( D1, D2). depending on the gross weight you enter the derate which in turn reduces the thrust for the climb. hence saving engine life but increasing your fuel burnt.
as for the 320 we didnt have this function on our acfts.
we use it on the 330's cause the acft is overpowered and never on the 340-300 since its powered by 4 hair driers( CFM enggines).

see ya.

airbus757
10th Sep 2007, 17:00
The 330 with Trents have CLB2, CLB1, and CLB. The 340-500 and 600 with Trents have the same. The 340-300 uses full climb thrust all the time.(at least the ones I have seen)

7

UP and Down Operator
10th Sep 2007, 22:06
On the A319 you don't have any of those derate selections (not in any of those I fly anyway).

The norm will be "open climb" which is max available climb thrust giving max rate of climb in prevailing conditions, or you can choose "vertical speed" and that combined with your selected speed/mach will normally give a reduced thrust as well.
Vertical speed is just not recommended for prolonged periods as it has been forgotten on various occasions and people have been flying themselves into stall conditions at high altitude, and it apparently creates an avfull mess when the coffee is leaving the cups due to odd A/C attitudes :E

Check Airman
10th Sep 2007, 22:26
Thanks folks. Seems that the baby buses don't have enough power for Airbus to consider derating them. Anybody has anything else to add?


UP and Down Operator, I thought only Boeing boys had to worry about stalling?:O

idg
10th Sep 2007, 23:58
I think the mini buses can have Climb Derate but only when the a/c has Pegasus FMGC and only when optioned by the airline. Happy to be proved wrong tho!

Nabla330
11th Sep 2007, 00:59
Up an Down Operator:

I think your mixing up things.

THRCLB1/ THRCLB2/THRCLB are obviously Auto Thrust related Modes. Left column on the FMA.

Don't know why you are writing about OP CLB and V/S Mode, as they are Vertical Functions of the Autopilot? 2nd column f.l.t.r on the FMA.

Those Modes weren't part of the question posted by "Check Airman"

westinghouse
11th Sep 2007, 06:23
hi again,

selecting a v/s is another way of reducing your climb thrust which equals to a derated climb.
however its mentioned in the book to enter the derate on the climb page of the mcdu. theres no mention of a v/s selection.
we noramlly use v/s to maintain the minimum climb required with maximum thrust. this is on the 343's where the at high wieghts the minimum climb can not be acheived.

bye.

Check Airman
11th Sep 2007, 13:47
Nabla,

When does the FMA show THRCLB1/ THRCLB2/THRCLB modes?


IDG,

Didn't know the bus had FMC options. How does one tell them apart?

Frank M
12th Sep 2007, 16:05
Yes,
Depending on the make/type of FMGEC installed in the bus, the options for the FMGECS are set through the AMI (Airline Modifiable Instructions) and OPC (Operational Program Configuration). My airline operates A330's with Pegasus FMGEC's and we chose to disable the D-CLB option. Other options include the use of lbs/kgs, default perf/idle factor, default acceleration heights, use of datalink etc.
As far as I know there is no way telling which options are chosen, other than looking for the defaults and knowing exactly what COULD be displayed on all pages. As the name implies, the AMI is modifiable by the airline (through the FMGEC vendor, in our case Honeywell), the OPC part is more "core-software" and needs to be modified by Airbus by incorporation of a MOD (e.g. deletion of the D-CLB option)

UP and Down Operator
12th Sep 2007, 16:29
Up an Down Operator:

I think your mixing up things.

THRCLB1/ THRCLB2/THRCLB are obviously Auto Thrust related Modes. Left column on the FMA.

Don't know why you are writing about OP CLB and V/S Mode, as they are Vertical Functions of the Autopilot? 2nd column f.l.t.r on the FMA.

Those Modes weren't part of the question posted by "Check Airman"

Maybe you should accept the fact that you, as the rest of us, don't know everything about the bus!!! - so please come down from your high horse :*
FACT is that FMGC's, as mentioned just above comes with a lot of different costumer modifications, and none of the A319 that I fly has the selection of derated climb. Hence, the only way we can reduce climbtrust from full pwr is to go into V/S.

UP and Down Operator, I thought only Boeing boys had to worry about stalling?:O I wish :\ I think they have more to worry about in general as some thinking is still left with the jockeys, but this v/s thing is one of the few "catch-outs" on the bus where people have spilt their coffee all over the place after having forgotten the selection and then flown into a high altitude stall. It is not recommended at high altitude and rarely nessesary as the climbrate above FL 250 is down around 1500-1800 ft/min anyway.

I don't know however, if the cost index becides setting cruise speeds ect also have an effect of the thrust output???

Admiral346
12th Sep 2007, 23:26
I used to fly A330/340/346 for LH and the 330 /346 have a derated climb thrust option. At my company that is because they bought thrust instead of engines, and as the engines are continously monitored anyways, the thrust is what the company pays for. So if you are lighter, you use derated climb thrust, simply by typing D1 or D2 into the FMS Performance page. If you need full climb thrust, you clear it. SOPs called for D1/D2 at certain T/O weights.

And having someone call my beautiful A343 engines, that never failed me in endless hours, "hairdriers" hurts, hurts very much, but the man is right. Even though they got me above the 747s on the crossing every time...

edit: the Cost Index does not have an impact on the thrust output at all, only on the climb/cruise/descent speed and optimum level on the progress page, just like on an A319...

westinghouse
15th Sep 2007, 12:49
hi,

im sorry i called them hair driers.( the 340 cfm engines). but it can be quite frustrating when atc keeps insiting you expedite to your level and the max you can get is ony 400fpm.
im trying to check if our engines had reduced thrust. think they were c2.

Nabla330
19th Sep 2007, 23:37
Maybe you should accept the fact that you, as the rest of us, don't know everything about the bus!!! - so please come down from your high horse



Up and Down Operator...don't take it too personal! I just wasn't sure what you were refering to. It is now clear to me after I read your reply.

By the way I think you're the one on the high horse if you say you know everything about the bus as you did...see quote above.

You would be the first person that claims to know everything about the bus. :ugh:

Never mind!

UP and Down Operator
20th Sep 2007, 13:09
Nabla330:
You would be the first person that claims to know everything about the bus. :ugh:


Maybe you should try and take on your glasses and read the same comment again, that you reffer to: Maybe you should accept the fact that you, as the rest of us, don't know everything about the bus!!! - so please come down from your high horse

WHERE did I state that I know everything about the bus????? Answer: NOWHERE!!!

Wonder if you read your manuals the same way you read posts here?? :ugh::ugh:

Nabla330
22nd Sep 2007, 16:04
Ok, I have to admit I rushed when I read your last post. :ouch: Appologies for the misunderstanding.

Believe me, I'm not stupid enough to think that I would know everything, especially about the Airbus.
Also, if you would know me in "real" life you would probably agree I'm not that type of person you are indirectly describing me as, namely as being arrogant. I would never dare to claim to know everything.

By the way, I think even some Airbus employees probably discover sometimes things about it they didn't realise before, because every airplane is full of surprises.

Just to clarify:
I never said you would be incompetent or anything similar (not even indirectly) in my first post. I just was asking you to clarify what you were trying to express when you started writing about V/S. I didn't understad that bit on your first post. Maybe because I'm stupid!? ;)

Maybe I should read more carefully next time, I agree. But I also think you should not assume/interpret things as you did with your following statement:

Wonder if you read your manuals the same way you read posts here?? .

No, I do read my manuals more carefully. By the way, there are more important things in life (definitely more import than reading/posting in PPRUNE) which I try to do more carefully or with more professionalism.

Let's behave like adults and stop being grumpy at each other!
Let's Bury the Hatchet.

;)

Cheers

SIDSTAR
30th Sep 2007, 11:32
Derated climb on an A320??? Guys, where we operate them they're already 'derated' at full climb thrust. Above 290 they climb so badly that they think they're a turboprop.

Seriously, derated clomb thrust unless you're very light should always result in a slower climb therefore more fuel burnt. Bad for the environment, bad for the company bottom line and ultimately bad for pilot's job prospects.