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How much fuel?

Old 30th Jun 2018, 19:46
  #41 (permalink)  
 
Join Date: Mar 2016
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Is the model not displayed on the FMC ident page?
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Old 1st Jul 2018, 14:40
  #42 (permalink)  
PJ2
 
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Originally Posted by Check Airman View Post
None of the airlines I've worked for have any provision for this. You'd have to dig into the ACARS to find the arrival fuel (which could well be meaningless if the plane's been on the ground for a while), and go out to the wing to speak to the fueller. We don't get fuel slips.
The airline I worked for required a manual (paper) log-book entry recording the fuel-on-board at shut-down. Also, we were delivered the fuel upload slip, in litres.

During FMC programming, a quick, approximate mental check of the fuel required in kilograms multiplied by 1.25* gave a good approximate amount required, in litres. If the fuel slip showed around that expected amount, we were good to go. The assumption of course is, that the on-board fuel at shut-down was accurate, and it appears as though it would have been in this incident.**


* 1.2658 @ SG 0.78 is the actual conversion factor
** Re 'arrival fuel could well be meaningless', (either from ACARS or the paper log), no, I don't think so. If I understand correctly, the B777 APU uses ~250kg/hr. While an APU usage of say, 10hrs is possible, (though, one hopes, rare!), that's only 2.5T of fuel, well within the rough figures and error-detecting range when using the above method. So, FOB at shutdown, 5.5T, fuel required 86T; 80.5 x 1.25 = 100k litres expected on the fuel slip. Actual fuel delivered in litres would have been approx 151k litres.

Last edited by PJ2; 1st Jul 2018 at 15:47.
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Old 1st Jul 2018, 15:27
  #43 (permalink)  
swh

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Originally Posted by Bksmithca View Post
For reasons that could not be determined, the aircraft's internal fuel-quantity indicator had registered the aircraft as a 777-200, which features a smaller centre fuel tank than the -200ER. This caused the aircraft's instruments to under-measure the amount of fuel on board.

So I'm thinking that this fuel issue has existed from day one of this aircrafts life so that means it's been under reporting the fuel load by 41Tons. So how many times have they landed above the allowable maximum landing weight and were these Heavy landing recorded and inspected?

Bk
SQ operated a number of their 777-200ERs in a regional configuration with a deactivated centre fuel tank effectively making them 200As, to do this the pin programming of the FGPU was changed by SQ. My guess is the FGPU from one of these aircraft was swapped onto this 200ER that was being used as an ER. Due to the SQ internal pin programming changes to the FGPU it performanced correctly as a 200A. The part was the correct part for the 200ER, just their poor Mx procedures could not catch the FGPU pin setup was wrong, it is Ann a SQ maintenance cockup, putting the wrong part on, unable to resolve a fuel discrepancy per the AMM.

Thus is what happens when good la engineers make procedures up on the fly not following the AMM and expect the aircraft to fix their mistakes.

The report is a joke, this is a systemic issue with SQs maintenance procedures.
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Old 1st Jul 2018, 15:33
  #44 (permalink)  
 
Join Date: May 2018
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I agree it is a maintenance error but to clarify some points. It is a FQPU (Fuel Quantity Processing Unit) and the configuration is changed by software, not pin programming.
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Old 1st Jul 2018, 16:08
  #45 (permalink)  
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The report is a joke,
It certainly doesn't answer all questions that would be helpful in further understanding how this occurred.

Canada's "Board of Inquiry Report" on the Gimli accident is far more thorough. Unfortunately, it is not available online.
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Old 1st Jul 2018, 21:03
  #46 (permalink)  
 
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Agree,.....but

Originally Posted by swh View Post


SQ operated a number of their 777-200ERs in a regional configuration with a deactivated centre fuel tank effectively making them 200As, to do this the pin programming of the FGPU was changed by SQ. My guess is the FGPU from one of these aircraft was swapped onto this 200ER that was being used as an ER. Due to the SQ internal pin programming changes to the FGPU it performanced correctly as a 200A. The part was the correct part for the 200ER, just their poor Mx procedures could not catch the FGPU pin setup was wrong, it is Ann a SQ maintenance cockup, putting the wrong part on, unable to resolve a fuel discrepancy per the AMM.

Thus is what happens when good la engineers make procedures up on the fly not following the AMM and expect the aircraft to fix their mistakes.

The report is a joke, this is a systemic issue with SQs maintenance procedures.
I do agree agree with your statement and even there were a lot of discussion about all those cheese holes,which finally aligned, the primary problem is not related to SQ maintenance, nor to the flight crew , it is much more related to the way the industry is moving to.
Based on my practical knowledge, it seems ridiculous to me, not to be seriously alerted by a difference of about 40 tons fuel uplift difference.
Further not stopping the departure and figuring out what is going wrong and try to work it out in accordance with the Fuel Measuring Stick Manual (FMSM) is kind of awkward. Maybe this task was not manageable for this particular ground crew within the given timeframe, still they should have had the opportunity to call for help.
​​​​​​​In these days,flight crews neither maintenance staff, do not have the opportunity to gain their experience and proper judgment over years, instead regulators like FAA and EASA are following the commercial pressure and will simply agree to the demands given by the industry, which means you will find 3000 FH blokes on the LH seat in an airliner and you will find a CAT A signing off a 777.
This simply leads into decision making which is task orientated instead of being "common sense" based, meaning by that, we rely more and more on automated aircraft systems while loosing our senses whats wright and wrong (don't get me wrong, I really appreciate all these aids in modern aircrafts,cause it makes my life much more easier).
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Old 2nd Jul 2018, 03:28
  #47 (permalink)  
 
Join Date: Aug 2010
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I had previously attended a flight where the lower forward hold was supposed to be empty on arrival but when we opened it up we found that there was around 12,000kgs which were not offloaded at the previous station.

Pilots had already left the aircraft but I met them when they took the next airplane out and told them what happenned... I also asked if they noticed anything on the flight in but they said everything was normal. Looks like the holes in the cheese didn''t line up but I can imagine a different scenario with a heavier load, shorter runway etc.

Plane was an MD-11 from SHJ.

Anilv
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Old 7th Aug 2018, 19:37
  #48 (permalink)  
 
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Canada's "Board of Inquiry Report" on the Gimli accident is far more thorough. Unfortunately, it is not available online.
https://reports.aviation-safety.net/...762_C-GAUN.pdf
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Old 7th Aug 2018, 19:42
  #49 (permalink)  
 
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Namely the fact all the V1 V2 and Vr and Vref was WRONG with a factor close to 1.3 or 1.2.
Says it all really.
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Old 7th Aug 2018, 21:03
  #50 (permalink)  
 
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Originally Posted by haughtney1 View Post
however, based on the story as published there is no way I would be moving the aircraft until I was satisfied.
Well, the crew had a "correct" (but erroneous) fuel quantity indication on their cockpit gauges, which agreed with the engineer's tank sticking results, and a plausible explanation for the uplift quantity discrepancy (Counter was not reset) which was incorrect, but not obviously so. I think a whole bunch of pretty diligent aircrew would be "satisfied" by this trap.
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Old 7th Aug 2018, 21:27
  #51 (permalink)  
 
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Originally Posted by mustafagander View Post
The only thing I would accept is a full magnastick check of all tanks
OK, I'll bite, if the problem is that you suspect too much fuel uplifted. And your cockpit fuel gauge fuel gauge indications show the wing tanks to be full ... and the engineers stick quantity calculations assume the wing tanks are full, and the wing tanks are in fact full, what useful information would have been added by sticking the wing tanks and confirming that they are indeed full, just like the engineers correctly assumed, and just like the cockpit gauges correctly indicated? ?


Originally Posted by mustafagander View Post
as well as a reasonable explanation of how come the uplift was so much higher than calculated.
Well, they believed that the delivery meter had not been reset to zero. If you have two completely independent measurements of the fuel on board (quantity gauges and engineers stick measurements) which agree, and show the correct load on board I think a lot of crew would tend to accept explanations that involve the uplift quantity being in error. Not having the results of the investigation in front of you before the incident, it's hard to know which pieces of information in front of you are in error.

Last edited by A Squared; 7th Aug 2018 at 21:46.
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