Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Is this a good way to burn off extra fuel

Tech Log The very best in practical technical discussion on the web

Is this a good way to burn off extra fuel

Old 27th Aug 2017, 07:45
  #61 (permalink)  
 
Join Date: Nov 2015
Location: Dog House
Age: 49
Posts: 779
Likes: 0
Received 0 Likes on 0 Posts
Thanks agg karan - so a last minute temp change is left to the pilot - good a hard fixed rule may least to rush and extra stress in the hot seat.

I would expect the same for a last minute taxi/runway change, that result in a time delay/advance would have the same result for the person in the hot seat - Once a plan is submitted, factors can change - but the plan has numerous built in contingencies including all weights of all kinds.

So I expect legally it is up to the pilot to decide if he wants 500kg less fuel or not - but to ride carbon fibre brakes at a higher power setting simply is wrong and due low temps and prolonged use massively increases the wear - and certainly not an official procedure that is approved by any manufacturer - hope this is recorded on the FDR.
Band a Lot is offline  
Old 27th Aug 2017, 10:50
  #62 (permalink)  
 
Join Date: Mar 2006
Location: USA
Posts: 2,541
Received 5 Likes on 3 Posts
Originally Posted by Band a Lot
Check Airman - show me 1 procedure for "Riding Brakes" in any manufactures manuals.

Any anyone intentionally caused excessive wear on anything - they should pay for it.

Hire a car and do a bunch of burnouts - expect to pay for it! The invoice will read something like " tires - excessive wear on rear (could be front).

regarding 3) So lets say temp range is 10-15C and it clicks over to 16C as you were about to go - what is your procedure? Not asking if information is readily available or not.
Show me where it says you can't ride the brakes. Like I said, it's not unheard of over here. Different philosophies I suppose. Filing a report would be seen as a gross overreaction to that technique.

Regarding the OAT, if the temp goes to 16, we simply request new data over ACARS. It shows up within a minute, we insert the uplink, and off we go. Is it much more complicated than that at your company?

And no, we can't just decide to go 500kg over MTOW. THAT would warrant 2-3 different reports. I find it curious that taking off above MTOW doesn't seem to bother you, as long as it's only a little, yet taking off with brakes in the green does. Where's your line when it comes to exceeding MTOW? 1000kg? 1500kg?
Check Airman is offline  
Old 27th Aug 2017, 11:54
  #63 (permalink)  
 
Join Date: Jun 2012
Location: india
Age: 39
Posts: 96
Likes: 0
Received 0 Likes on 0 Posts
[QUOTE=Band a Lot;9874109]Thanks agg karan - so a last minute temp change is left to the pilot - good a hard fixed rule may least to rush and extra stress in the hot seat.

Yes compliance would be indeed stressful regardless of it being last min. But has to be done.

Unpractical but really necessary
agg_karan is offline  
Old 27th Aug 2017, 12:31
  #64 (permalink)  
 
Join Date: Jun 2007
Location: Wanderlust
Posts: 3,411
Likes: 0
Received 3 Likes on 1 Post
Check Airman
Show me where it says you can't ride the brakes
Quoted below from FCTM:

TAXI SPEED AND BRAKING On long, straight taxiways, and with no ATC or other ground traffic constraints, the PF should allow the aircraft to accelerate to 30 kt, and should then use one smooth brake application to decelerate to 10 kt. The PF should avoid continuous brake applications.
vilas is offline  
Old 27th Aug 2017, 14:20
  #65 (permalink)  
 
Join Date: Jan 2015
Location: Near St Lawrence River
Age: 53
Posts: 198
Likes: 0
Received 0 Likes on 0 Posts
Show me where it says you can't ride the brakes
Show me where it says you can't taxi backwards on thrust reversers.

How about announcement "Flight attendants prepare the cabin for an imminent rejected take-off"
_Phoenix is offline  
Old 27th Aug 2017, 15:33
  #66 (permalink)  
 
Join Date: Jun 2007
Location: Wanderlust
Posts: 3,411
Likes: 0
Received 3 Likes on 1 Post
_Phoenix
Can you elucidate what you are saying?
vilas is offline  
Old 27th Aug 2017, 17:46
  #67 (permalink)  
Thread Starter
 
Join Date: Apr 2008
Location: nowhere
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by vilas
_Phoenix
Can you elucidate what you are saying?
He is agreeing with you.
JammedStab is offline  
Old 27th Aug 2017, 17:47
  #68 (permalink)  
 
Join Date: Mar 2006
Location: USA
Posts: 2,541
Received 5 Likes on 3 Posts
Originally Posted by vilas
Check Airman

Quoted below from FCTM:
Touché

Agreed that it isn't preferred, but sometimes you gotta do what you gotta do.
Check Airman is offline  
Old 27th Aug 2017, 17:50
  #69 (permalink)  
 
Join Date: Jan 2015
Location: Near St Lawrence River
Age: 53
Posts: 198
Likes: 0
Received 0 Likes on 0 Posts
Just a joke Vilas, but technically correct how to burn more fuel before lift-up. Only a component of the reverse thrust acts on horizontal, therefore more fuel to burn. "Simulated" rejected take-off and an another line-up should deplete the extra fuel.
_Phoenix is offline  
Old 27th Aug 2017, 19:42
  #70 (permalink)  
 
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes on 0 Posts
OMG: And I thought this was a chat forum for professional pilots. Where is this discussion going? Up the ring yang, me thinks..
RAT 5 is offline  
Old 28th Aug 2017, 01:10
  #71 (permalink)  
Thread Starter
 
Join Date: Apr 2008
Location: nowhere
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Check Airman
Touché

Agreed that it isn't preferred, but sometimes you gotta do what you gotta do.
So if you gotta burn fuel, find a place to stop, add thrust and burn it.
JammedStab is offline  
Old 28th Aug 2017, 03:50
  #72 (permalink)  
 
Join Date: Nov 2004
Location: bkk
Posts: 285
Likes: 0
Received 0 Likes on 0 Posts
PROBLEM

We are at the holding point at an actual weight exactly at RTOW.The tower advise(or we become aware) that the oat has risen by 3 degrees.I ask the copilot to re-check the RTOW."Sir we are 500kgs over our revised RTOW now".

SOLUTION: "Please hand amend the loadsheet to increase the TAXI FUEL BY 500kgs".Done this several times in the past 28 years of big jet PIC.......Never had a problem yet.

INSTRUCTOR: Alcohol is a dangerous drug for pilots.Its also addictive.
ME: Sir, ive been drinking alcohol every day of my life since I turned 18 and I have never found it addictive yet.....Pete.
piratepete is offline  
Old 28th Aug 2017, 04:56
  #73 (permalink)  
 
Join Date: Mar 2006
Location: USA
Posts: 2,541
Received 5 Likes on 3 Posts
This has got to be the most curios thread on pprune I've seen in a while. Some people seem to be more willing to knowingly depart overweight, than heat the brakes up a bit. Live and learn...
Check Airman is offline  
Old 28th Aug 2017, 05:06
  #74 (permalink)  
 
Join Date: Jun 2005
Location: USA
Posts: 951
Likes: 0
Received 1 Like on 1 Post
And just as many prefer to stop and burn the excess fuel off before taking off. No unnecessary additional brake heat or wear and no overweight takeoff. Satisfactory?
westhawk is offline  
Old 28th Aug 2017, 05:42
  #75 (permalink)  
 
Join Date: Jun 2007
Location: Wanderlust
Posts: 3,411
Likes: 0
Received 3 Likes on 1 Post
From the answers it is clear that legally the fuel must be burned. Riding brakes with power will definitely cause more wear but short term rise in temperatures is uncertain and can affect breaking efficiency. Not a good choice. But what is the problem if you taxied for same amount time as originally planned by taking a longer route?
vilas is offline  
Old 28th Aug 2017, 10:28
  #76 (permalink)  

PPRuNe Person
 
Join Date: Jun 2001
Location: see roster
Posts: 1,268
Likes: 0
Received 0 Likes on 0 Posts
This is the weirdest thread in a while.

Icelanta on P1 of this thread is correct.

The fuel does NOT have to be burned prior to t/o. If the flight plan and load sheet were legal on dispatch, in the outfit I work for, the taxi fuel usage need not be considered provided any exceedance is consider to be minor. 500kg in 396000kg is minor IMO.

In our SOP there is NO requirement to check any aircraft weight indication just prior to t/o, this would rely on fuel indications being dead accurate, which they aren't, and the ZFW being dead accurate, which it isn't. Using actual passenger weights are we? No! The legalities are covered by the load sheet, the performance is covered by the margin of error built in.

I would expect that any wide-body departure on any day is actually +/- 2000kg of what you think it is.

Anyone who deliberately increases their brake energy before a max TOW t/o in a wide body should be removed from the line for remedial ground school training.

The OP wrote:
Widebody jet, 30 degrees C, full takeoff thrust required, max taxi weight but due to a runway change, the planned taxi routing runway is shorter than expected.

500 kg need to be burned before takeoff is legal.
This last sentence is the incorrect assumption. Take the 500kg into the air with you as a bonus.

Last edited by overstress; 28th Aug 2017 at 10:47.
overstress is offline  
Old 28th Aug 2017, 10:56
  #77 (permalink)  
 
Join Date: Apr 2010
Location: IRS NAV ONLY
Posts: 1,233
Likes: 0
Received 1 Like on 1 Post
In our SOP there is NO requirement to check any aircraft weight indication just prior to t/o, this would rely on fuel indications being dead accurate, which they aren't, and the ZFW being dead accurate, which it isn't. Using actual passenger weights are we? No! The legalities are covered by the load sheet, the performance is covered by the margin of error built in.
The thing is, you can't really check iz actual ZFW (as in actual cargo/pax weight, not loadsheet) is the within MZFW, but you can check if loadsheet ZFW + FOB is below MTOW, which I believe is legally binding. Otherwise if you are RTOW limited and wanted to take more extra fuel, you could just increase taxi fuel and still be legal?

Same goes for the MLW limitation I guess, loadsheet itself isn't enough, but you have to check that ZFW (from loadsheet) + actual FOB on landing is less than MLW.

Fully agree on the brake point though, I think anybody using brakes against thrust before departure on any type of aicraft should get some extra training.
FlyingStone is offline  
Old 28th Aug 2017, 11:29
  #78 (permalink)  
 
Join Date: Jan 2014
Location: N5109.2W10.5
Posts: 720
Likes: 0
Received 0 Likes on 0 Posts
Hi overstress,
500kg in 396000kg is minor IMO.
The BEA would agree with you.
See accident report to Concorde July 2000, F-BTSC https://www.bea.aero/uploads/tx_elyd...-sc000725a.pdf See Conclusion, 3.1 Findings:

"Taking into account the fuel not consumed during taxiing, the aircraft’s takeoff
weight in fact exceeded the maximum weight by about one ton. Any effect on
takeoff performance from this excess weight was negligible."
Goldenrivett is offline  
Old 28th Aug 2017, 12:12
  #79 (permalink)  
 
Join Date: Mar 2006
Location: USA
Posts: 2,541
Received 5 Likes on 3 Posts
Originally Posted by FlyingStone
The thing is, you can't really check iz actual ZFW (as in actual cargo/pax weight, not loadsheet) is the within MZFW, but you can check if loadsheet ZFW + FOB is below MTOW, which I believe is legally binding. Otherwise if you are RTOW limited and wanted to take more extra fuel, you could just increase taxi fuel and still be legal?
That's what I don't understand about the EU system. We all know that we're using assumed weights here, but under the FAA, you're required to use the best available information regarding your actual weight.

Our ops manual specifically states that if actual taxi burn is less than planned, the fuel must be burned prior to commencing the takeoff roll if we are above MTOW. No wiggle room.

The NTSB report would open with "The PIC attempted to depart with an overweight aircraft..."
Check Airman is offline  
Old 28th Aug 2017, 13:15
  #80 (permalink)  
 
Join Date: Nov 2015
Location: Dog House
Age: 49
Posts: 779
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by overstress
This is the weirdest thread in a while.

Icelanta on P1 of this thread is correct.

The fuel does NOT have to be burned prior to t/o. If the flight plan and load sheet were legal on dispatch, in the outfit I work for, the taxi fuel usage need not be considered provided any exceedance is consider to be minor. 500kg in 396000kg is minor IMO.

In our SOP there is NO requirement to check any aircraft weight indication just prior to t/o, this would rely on fuel indications being dead accurate, which they aren't, and the ZFW being dead accurate, which it isn't. Using actual passenger weights are we? No! The legalities are covered by the load sheet, the performance is covered by the margin of error built in.

My posts also had a filed flight plan as being ok with this "minor" change - BUT never wit ridining brakes

I would expect that any wide-body departure on any day is actually +/- 2000kg of what you think it is.

Anyone who deliberately increases their brake energy before a max TOW t/o in a wide body should be removed from the line for remedial ground school training.

The OP wrote: This last sentence is the incorrect assumption. Take the 500kg into the air with you as a bonus.

My posts also had a filed flight plan as being ok with this "minor" change - BUT never with ridining brakes and the manual from past post seems to agree - bar a fool that thinks longer taxy time = brakes applied. Now honestly I hope he/she is not a real pilot or has plans to be.
Band a Lot is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.