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Is this a good way to burn off extra fuel

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Is this a good way to burn off extra fuel

Old 21st Aug 2017, 12:15
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Unless max structural TOW restricted : Start Apu and do a No Engine Bleed t/o?Gives me some 1300kg more on the 738.
Been field and or obstacle restricted a few times this summer.Good fun.

Have also had some backtracks to get headwind when ATC like to do Ils27 and 5 to 10 kts tailwind departures on 09 due to lack of taxiway.

I just love these local Kings in the tower telling me what I have to accept or not.

To cook the brakes to get legal is loosing the big picture, indeed.
The Dutch call it MirenNauken I think.
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Old 21st Aug 2017, 13:40
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Originally Posted by BluSdUp

I just love these local Kings in the tower telling me what I have to accept or not.
These "local kings in the tower" might just want to offer you a favor with less taxi time and expedite air traffic flow on the airport. They don't know the performances of every single airplane every single day. Usually a nice "unable rwy 09 due performances" is all it takes.
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Old 21st Aug 2017, 13:57
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Originally Posted by BluSdUp
The Dutch call it MirenNauken I think.
BluSdUp you mean Mierenneuken a.k.a. Nitpicker. However that is not the right expression in this context.


Just set the parking brake and burn the fuel off. No worries about brake tempratures increasing.
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Old 22nd Aug 2017, 08:08
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Originally Posted by gearlever
Well IMHO it depends WHY is TOW limited. Structural? Performance? Landing weight?

If it's the latter our SOP allow to assume a 50% burn off of contingency fuel, means increased trip fuel....
Given "full take-off thrust required" one would assume the take-off is performance limited.
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Old 22nd Aug 2017, 13:18
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It's not a good idea because break temperatures will peak after take off and could be hazardous and also wear and tear. If it was landing weight limited it could be burnt in the air otherwise as suggested by many just idle away those extra holding some where.
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Old 22nd Aug 2017, 16:40
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Originally Posted by vilas
If it was landing weight limited it could be burnt in the air
Not necessarily. We can't do that.
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Old 22nd Aug 2017, 16:59
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Why not? Cruise lower/fly faster will burn more
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Old 22nd Aug 2017, 17:37
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Well, if redispatched with the higher fuel burn to make it fit, then yes.

But "We'll just launch, and burn it off in the air" at higher than MTOW is a no-go. We only see limit codes for a few things, and this is not one of them; so we don't even know what the limiting factor is. While seeing that the LDW matches the MLDW is a good clue, something else could also be just as limiting at the same time, and we'd have no way to know.

Plus, we'd be violating 121.195: "No person operating a turbine engine powered airplane may take off that airplane at such a weight that (allowing for normal consumption of fuel and oil in flight to the destination or alternate airport) the weight of the airplane on arrival would exceed the landing weight set forth in the Airplane Flight Manual for the elevation of the destination or alternate airport and the ambient temperature anticipated at the time of landing."
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Old 22nd Aug 2017, 17:41
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500 kg need to be burned before takeoff is legal. No problem, just ride the brakes with a higher than normal thrust setting.
Feel sorry for the hold behind you inline, not to mention FOD issues for you and others...
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Old 22nd Aug 2017, 19:33
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500 kg need to be burned before takeoff is legal. No problem, just ride the brakes with a higher than normal thrust setting.
NEVER ride the brakes.
SET the brakes instead.
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Old 22nd Aug 2017, 21:26
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I have to say it’s not something I would get really worried about (the marginal MTOW possible exceedance)?

a) On a widebody with a reasonable amount of airframe hours and a decent passenger load, I’d be surprised if the *actual* weight of the aircraft was within a couple of tons either way of what you thought it was.

b) What’s the worst that can happen? Even with a V1 cut is a couple of hundred kg either way going to make a difference? Just different line up and thrust setting techniques can affect things more if you’re RLL.

c) Who’s counting, anyway?

d) Even if I was worried, I certainly wouldn’t ride the brakes on an above-idle thrust setting. Just when you might need all of the braking performance, you deliberately remove some of it? Much rather take +500kg with cold brakes, thank you!

Betteridge’s Law applies here, I think.

Last edited by FullWings; 22nd Aug 2017 at 21:48.
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Old 22nd Aug 2017, 21:51
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c) Who’s counting, anyway?
Wow, incredible post!

What other things do you ignore?

a) you know the actual weight is a couple of tons either way, so whats another 500kg?
b) Whats the worst that can happen? (other than you driving?)
c) Whos counting? (Other than your conscious attempt to take off overweight) I suppose even you realize the standards that set that MTOW have a myriad of factors, none of which, the performance people who loaded the ac have calculated in loading the ac?
Go long, or screw up, and you will see who is counting.
d) I can see where you would be concerned about braking, especially when you dont care about DEP overweight.

kudos to the drivers who decide on ways to burn off 500kg, than simply violate the law.
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Old 22nd Aug 2017, 22:16
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Originally Posted by FullWings

c) Who’s counting, anyway?
The CAA after you've run off the end of the runway. Sure, you may have run off the end of the runway anyway at a max performance, max weight, take-off, with a max speed reject, but if you've knowingly taken off above the RTOW then you'd be in a deep


a) On a widebody with a reasonable amount of airframe hours and a decent passenger load, I’d be surprised if the *actual* weight of the aircraft was within a couple of tons either way of what you thought it was.
That may be true. You may already be a couple of tonne overweight. There are some margins built into the take-off performance calculations to allow for unknown variations, I'm not about to intentionally use up those margins with a known variation.

d) Even if I was worried, I certainly wouldn’t ride the brakes on an above-idle thrust setting. Just when you might need all of the braking performance, you deliberately remove some of it? Much rather take +500kg with cold brakes, thank you!
There is another option you know? Just park somewhere and wait for the fuel to burn off.
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Old 22nd Aug 2017, 22:48
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Fullwings

You remind me of a young lad I know.
Load her up until she starts sinking, toss ca 50lbs back on the dock and off you go, just 10% overload.
Oh, and that only worked with the one on CAP floats.
Allways carry a correct loadsheet.
And dont get caught!
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Old 22nd Aug 2017, 22:58
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Observation: inaccuracies in payload weight records

Problem: takeoff weight is possibly above limit

Conclusion: OK to add more weight

.... nice.
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Old 22nd Aug 2017, 23:15
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On a widebody with a reasonable amount of airframe hours and a decent passenger load, I’d be surprised if the *actual* weight of the aircraft was within a couple of tons either way of what you thought it was.
and you are a widebody driver?

Well IMHO it depends WHY is TOW limited. Structural? Performance? Landing weight?
You dont know why the performance people have calculated this, Did you think of what was taken into account? Their PROFESSION is to optimize the flight, your PROFESSION should NEVER second guess them.

Last edited by underfire; 22nd Aug 2017 at 23:44.
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Old 23rd Aug 2017, 02:12
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"How do you plead?"

"Not guilty by reason of 'Widebody.'"

"Case dismissed. Clearly this man shouldn't be in any sort of legal trouble."

Seriously?

We put numbers on limits so we know when to say enough is enough. Why don't you leave the engineer business to Boeing and Airbus? They already account for the slop so you don't have to.
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Old 23rd Aug 2017, 02:13
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Originally Posted by underfire

You dont know why the performance people have calculated this, Did you think of what was taken into account? Their PROFESSION is to optimize the flight, your PROFESSION should NEVER second guess them.
We certainly know if it is landing weight, structural, or performance. The performance people do the performance calculations, that is all.
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Old 23rd Aug 2017, 05:25
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Seriously? You think that brake temperatures increase significantly when the wheels aren't turning?
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Old 23rd Aug 2017, 06:14
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Originally Posted by Vessbot
Well, if redispatched with the higher fuel burn to make it fit, then yes.

But "We'll just launch, and burn it off in the air" at higher than MTOW is a no-go. We only see limit codes for a few things, and this is not one of them; so we don't even know what the limiting factor is. While seeing that the LDW matches the MLDW is a good clue, something else could also be just as limiting at the same time, and we'd have no way to know.

Plus, we'd be violating 121.195: "No person operating a turbine engine powered airplane may take off that airplane at such a weight that (allowing for normal consumption of fuel and oil in flight to the destination or alternate airport) the weight of the airplane on arrival would exceed the landing weight set forth in the Airplane Flight Manual for the elevation of the destination or alternate airport and the ambient temperature anticipated at the time of landing."
At my company, if we're landing weight limited, the paperwork will show it explicitly. A quick message to dispatch will have us on the way in minutes.
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