AF 777 wrong weight inputs, off by 100 tonnes?
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AF 777 wrong weight inputs, off by 100 tonnes?
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Boeing customer option on the 777 is to remove Gross weight entry from LSK1. Not sure if AF purchased this option on the 77F fleet (2 aircraft).
MTOW on their 77Fs is 347,000kgs (Highest option on the -200LRF).
Operating CDG-MEX fuel would be 90-95T. With a payload of 80-100T TOW would be 320t up to MTOW. If indeed they were off by 100t they either entered the wrong TOW or ZFW in the TOW field (if that is enabled on their aircraft). EK almost lost a A345 at YMML a while back due to the same mistake. Gross Weight being entered 100t lower and the crosscheck wasnt done correctly.
Since then, they have purchased the the Gross Weight try field REMOVED option on the 777 fleet and I assume the Airbus too if that is an option. And also disabled it on previously delivered B777s. This being one step along with additional training and emphasizing of doing the weight & balance calculations separately and crosschecking.
At least the AF crew realized acceleration was insufficient and aborted before going off the end...However you do wonder if they were experienced on type why they would let themselves get away with a far too big de-rate/assumed temp. If you are running the takeoff performance numbers for a 11h+ sector, and the assumed temp comes back as TO-65C that should raise a red flag....
MTOW on their 77Fs is 347,000kgs (Highest option on the -200LRF).
Operating CDG-MEX fuel would be 90-95T. With a payload of 80-100T TOW would be 320t up to MTOW. If indeed they were off by 100t they either entered the wrong TOW or ZFW in the TOW field (if that is enabled on their aircraft). EK almost lost a A345 at YMML a while back due to the same mistake. Gross Weight being entered 100t lower and the crosscheck wasnt done correctly.
Since then, they have purchased the the Gross Weight try field REMOVED option on the 777 fleet and I assume the Airbus too if that is an option. And also disabled it on previously delivered B777s. This being one step along with additional training and emphasizing of doing the weight & balance calculations separately and crosschecking.
At least the AF crew realized acceleration was insufficient and aborted before going off the end...However you do wonder if they were experienced on type why they would let themselves get away with a far too big de-rate/assumed temp. If you are running the takeoff performance numbers for a 11h+ sector, and the assumed temp comes back as TO-65C that should raise a red flag....
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THAT OLD CHESTNUT AGAIN?!
Avoid? Not in this case, though done every day by all FMS loading crews.
Trap? Not in this case, could be by structured ritual during loading.
Mitigate? Well done guys, you didn't scrape metal nor kill/physically injure anyone!
IIRC, Singapore Airways did the same by 100 tons a few years ago, (fuel?), in a 744 and scraped the tail so much that the ground engineers were surprised the APU stayed in place.
Lots of stuff re this topic in the Boeing Magazine since, but still someone somewhere tries it again.
A formal ritual involving both/all pilots present on the flight deck, sterile flight deck with no distractions from CC or ground staff, would help to stop this one dead. So would the practise of calculating, by brain, a gross error Vspeed, viz V2, from the CFP and annotating the CFP with it at the briefing stage, then comparing when finally loaded in the flight deck.
The 73NG used to come out with a very close last 2 digits of V2 @ flap 5 by subtracting 25 from the TOW within a knot or two. Of course these days there are too many variations on thrust reduction like derates plus TASS for takeoffs so this may not be valid any longer. But it certainly kept me and others out of the trees at screen height when I was operating.
There, that's my pennyworth of problem-solving. I look forwards now to the inevitable flood of widgets, gadgets and software mods proposed by all the wannabe aircraft engineers/pilots out there, knowing that even if such hardware/mods get approved for use, it will be years before they are incorporated in ALL 'frames.
Meantime we will read more stories of gut-wrenching moments as the next crew to do this realise they are going nowhere fast and may not miss the hard stickey uppy bits at the end of or beyond the stopway and a careers/lives are about to end.
Trap? Not in this case, could be by structured ritual during loading.
Mitigate? Well done guys, you didn't scrape metal nor kill/physically injure anyone!
IIRC, Singapore Airways did the same by 100 tons a few years ago, (fuel?), in a 744 and scraped the tail so much that the ground engineers were surprised the APU stayed in place.
Lots of stuff re this topic in the Boeing Magazine since, but still someone somewhere tries it again.
A formal ritual involving both/all pilots present on the flight deck, sterile flight deck with no distractions from CC or ground staff, would help to stop this one dead. So would the practise of calculating, by brain, a gross error Vspeed, viz V2, from the CFP and annotating the CFP with it at the briefing stage, then comparing when finally loaded in the flight deck.
The 73NG used to come out with a very close last 2 digits of V2 @ flap 5 by subtracting 25 from the TOW within a knot or two. Of course these days there are too many variations on thrust reduction like derates plus TASS for takeoffs so this may not be valid any longer. But it certainly kept me and others out of the trees at screen height when I was operating.
There, that's my pennyworth of problem-solving. I look forwards now to the inevitable flood of widgets, gadgets and software mods proposed by all the wannabe aircraft engineers/pilots out there, knowing that even if such hardware/mods get approved for use, it will be years before they are incorporated in ALL 'frames.
Meantime we will read more stories of gut-wrenching moments as the next crew to do this realise they are going nowhere fast and may not miss the hard stickey uppy bits at the end of or beyond the stopway and a careers/lives are about to end.
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So this time it was Air Chance?
Another previous such instance as below, very hairy! :
Emirates Flight 407 - Wikipedia, the free encyclopedia
Actually got airborne, doing some major damage on the way, then returning after dumping fuel.
Emirates Flight 407 - Wikipedia, the free encyclopedia
Actually got airborne, doing some major damage on the way, then returning after dumping fuel.
Last edited by seafire6b; 29th May 2015 at 17:58. Reason: OCD!
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http://www.taic.org.nz/ReportsandSafetyRecs/AviationReports/tabid/78/ctl/Detail/mid/482/InvNumber/2003-003/language/en-US/Default.aspx?SkinSrc=%5BG%5Dskins%2FtaicAviation%2Fskin_avia tion
"To compensate, pilots had to override the automated settings and order up maximum power from the aircraft's two engines.
Air France confirmed the incident in response to a query from Reuters and said the crew had been taken off flying duties once they had reached their initial destination."
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To quote... Emirates Flight 407 - Wikipedia, the free encyclopedia
Airbus are going to find a Software update....
That will be nice.... We can all sleep safe in our beds.
Airbus are going to find a Software update....
That will be nice.... We can all sleep safe in our beds.
I REALLY SHOULDN'T BE HERE
I normally scribble down estimated Green Dot speed when we decide on the fuel load then compare it to what the FMGC spits out. Usually within 2 knots - pretty bulletproof cross check.
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To save others the trouble... Discussion: Why don't aircraft weight themselves?
http://www.pprune.org/tech-log/31510...hemselves.html
http://www.pprune.org/tech-log/31510...hemselves.html
@IC quote "To save others the trouble... Discussion: Why don't aircraft weight themselves?"
...and fly themselves? That's coming too.
Mistakes happen, it's the crews who catch them before the bad consequences that keep us safe. If the airplane had its own scales in the gear, that might be a truly good cross-check, but if it becomes the primary means of establishing the GWT, the crew's mental cross-check is likely to vanish.
Failures occur in any electro-mechanical system, and I doubt the automatic system would have the integrity/redundancy to be the primary means. But it would no doubt be used that way.
...and fly themselves? That's coming too.
Mistakes happen, it's the crews who catch them before the bad consequences that keep us safe. If the airplane had its own scales in the gear, that might be a truly good cross-check, but if it becomes the primary means of establishing the GWT, the crew's mental cross-check is likely to vanish.
Failures occur in any electro-mechanical system, and I doubt the automatic system would have the integrity/redundancy to be the primary means. But it would no doubt be used that way.
The SQ 744 actually had the APU catch on fire. They rushed the first circuit and had to go around. The issue with that one is that the Capt. had come off the A340 so he was not surprised to see a V1 around the 12ish mark. The TOW was 397T so one of the 3 crew should have queried the box numbers. As someone said though gross error checks are not taught so much these days.
The thread referenced in post #10 mentions STAN (Sum Total And Nosewheel)
I acquired this paperweight as a reminder of technology that didn't put me out of a job.
I acquired this paperweight as a reminder of technology that didn't put me out of a job.
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The electronic weighing system on the B747-200 freighters we flew in AHK some years ago I recall were fairly accurate(ish) and reliable(ish), . . .but hey...we had flight Engineers and subsequently never had a problem with takeoff performance over a very wide variety of departures. 
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Best Guess Best Gross Error Check
A poster above uses best guess green dot. My version is to best guess a V1 and Flex Temp. Bit of fun and makes the brief interactive as we discuss any differences between best guess and EFB.
Big pants suggests that best guess at V1 and flex temp might be good.
Problem with that idea is that there's so many variables on V1 other than weight, such as wet versus dry. I'd suggest VR/V2 for a given weight and flap setting would be a better indication to compare to your flex.
We've recently switched to Airbus fly smart iPad software, it's a great bit of kit but I've certainly started doing a lot more gross error checking of speeds flap setting and weights prior to departure.
Our outfit recently had a flap 2 takeoff on a runway which should have been set to flap 1, luckily this was a 'conservative failure', had it been the other way around there would have been much gnashing of teeth. As a result of this we found out that the flap indication in the MCDU provides noTO CONFIG warning in the event that it does not match the selected flap. My point being, it's not only the weight being correct that is critical.
Problem with that idea is that there's so many variables on V1 other than weight, such as wet versus dry. I'd suggest VR/V2 for a given weight and flap setting would be a better indication to compare to your flex.
We've recently switched to Airbus fly smart iPad software, it's a great bit of kit but I've certainly started doing a lot more gross error checking of speeds flap setting and weights prior to departure.
Our outfit recently had a flap 2 takeoff on a runway which should have been set to flap 1, luckily this was a 'conservative failure', had it been the other way around there would have been much gnashing of teeth. As a result of this we found out that the flap indication in the MCDU provides noTO CONFIG warning in the event that it does not match the selected flap. My point being, it's not only the weight being correct that is critical.