AF 777 wrong weight inputs, off by 100 tonnes?
Join Date: Jun 2002
Location: Wor Yerm
Age: 68
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
This 100 tonne error is regularly made by aircrew in all sorts of airlines. Mortals only get to hear about the incidents where there is some noise attached. What is clear is that no airline or manufacturer appears to have bullet proof method of prevention. A manually (yes, in this day and age) calculated speed (V2 or Vfs etc.) guess based on estimated load, DOW and fuel compared with the figures generated by the loadsheet might be the way forward. More silicon is probably not a good idea because it may use the use the same rubbish as input.
Join Date: Apr 1999
Location: Manchester, UK
Posts: 1,958
Likes: 0
Received 0 Likes
on
0 Posts
Sadly, because of the design of electronic performance programmes, these are going to keep on happening. It's easy enough to scoff at how silly someone must have been to make a 100 tonne error, but that's not how these accountancy based systems work. We're talking about a single misplaced digit. With old style tables a gross error was far less likely.
Join Date: Apr 2010
Location: New Forest
Posts: 143
Likes: 0
Received 0 Likes
on
0 Posts
STAN
Re post No 15. Yes indeed, Stan has existed for many years but is not completely infallible. We had it on the old Vanguard freighter, the Merchantman (VC9). It had not been certified for the aircraft (IIRC), so had no limits attached but it did give a rough idea. I very nearly came unstuck but was saved by STAN. I have ALWAYS, from my days as a Second Officer to Senior Captain, done a rough gross error check. I believe its called "professionalism". In the case in point, the total weights were approx correct but, being the middle of the night in the middle of winter and considering that some cretin had kicked the plug out of the weighing machine's heater, it recorded all pallets as having the same weight. Coincidentally, the total was almost correct. However, the individual weights were at great variance and when, on doing the STAN reading whilst taxying out and the C of G reading was way out, as we came to a stop I could feel the aircraft trying to settle down on to its tail.
Thank you, STAN!
Thank you, STAN!
Last edited by Prober; 31st May 2015 at 22:23. Reason: Cogency
Join Date: Apr 2008
Location: nowhere
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Of course the smaller the plane, the greater the amount of percentage error is a 100 ton mistake.
So what do you do to prevent this. We put the planned ZFW in the ZFW column of the FMC upon initial entry. Then when actual is read out, I point at the ZFW in the FMC and then enter it. A large difference should be questioned.
The OPT initial calculation is from the planned GTOW number on the flight plan(the ZFW number is not used). A significant difference here upon final calculation should also be questioned.
I also look at the V2 speed and see if it makes sense for general weight.
Any other suggestions are welcome. Obviously it can happen.
So what do you do to prevent this. We put the planned ZFW in the ZFW column of the FMC upon initial entry. Then when actual is read out, I point at the ZFW in the FMC and then enter it. A large difference should be questioned.
The OPT initial calculation is from the planned GTOW number on the flight plan(the ZFW number is not used). A significant difference here upon final calculation should also be questioned.
I also look at the V2 speed and see if it makes sense for general weight.
Any other suggestions are welcome. Obviously it can happen.
Join Date: Dec 2001
Location: what U.S. calls Žold EuropeŽ
Posts: 941
Likes: 0
Received 0 Likes
on
0 Posts
And reduce your on-wing engine life by how much?
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes
on
0 Posts
JammedStab's method should work: i.e. a comparison between planned/expected data and actual data. Further, I think there needs to be a whole attitude change. Many of us were brought up in the era of 'gross error checks'. There were little tricks we all used to have a 'ball-park figure' in our heads. This covered many items. Today's education, in so many fields, is to use japanese brains and believe what they tell you; no gross error check in your own brain. This has been contributed to by the lack of mental arithmetic in schools I often get cadets on the TQ course who struggle with basic speed/distance/time calculations. Ground speed/ROD/VS calculations. It's all VNAV and FMC to find the answers. Guys who use calculators to add up load sheets etc. Often it's slower anyway, but they have not been schooled in this way and given the tools.
Join Date: Aug 2006
Location: earth
Posts: 31
Likes: 0
Received 0 Likes
on
0 Posts
I liked when, based on our estimated TOW, we would preselect V2 in the MCP, then once the data was in, comparing the speeds was an easy way to see if we had made a mistake somewhere. But somehow we don't do this anymore 
Join Date: Apr 2008
Location: nowhere
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
I think that might be more of a loading position problem than a V-speed problem.
Plus, some jet freighters have a tailstand pushing up on the tail of the aircraft for loading during the walkaround. The other day, there was no nosegear oleo showing, so it was checked after the tailstand was later removed.
Plus, some jet freighters have a tailstand pushing up on the tail of the aircraft for loading during the walkaround. The other day, there was no nosegear oleo showing, so it was checked after the tailstand was later removed.
Join Date: Jan 2008
Location: Europe
Posts: 135
Likes: 0
Received 0 Likes
on
0 Posts
The crew actaully caught the slip: TOGA set, limit the pitch angle in order to protect the tail, retract the flaps and slats way over the computed speeds. Pretty good mitigation of the initial error, no harm done.
6 years of hard work changing everything in the airline operations and the company safety culture, and here we are wondering why we're facing two near disasters in a couple of week.
BTW, answer to post 26: a LOSA audit is being done as we speak, the second one in 3 years. And for the halfwits tinking like post 27, the B777/744 fleet manager offerded his resignation yesterday.
This is being taken seriously.
6 years of hard work changing everything in the airline operations and the company safety culture, and here we are wondering why we're facing two near disasters in a couple of week.
BTW, answer to post 26: a LOSA audit is being done as we speak, the second one in 3 years. And for the halfwits tinking like post 27, the B777/744 fleet manager offerded his resignation yesterday.
This is being taken seriously.
Join Date: Apr 2005
Location: "this is where the magic happens"
Posts: 260
Likes: 0
Received 0 Likes
on
0 Posts
6 years of hard work changing everything in the airline operations and the company safety culture, and here we are wondering why we're facing two near disasters in a couple of week.
Could it perhaps be that the problems with AF's safety culture are a lot older than 6 years? Air France accidents and incidents - Wikipedia, the free encyclopedia
Could it also be that perhaps the real problem is not really the safety culture, but rather an extremely arrogant superiority complex culture, also known as French chauvinism? An inbred culture that is not open for change? A culture that prevents fresh (foreign!? English?!) ideas and lessons to take root? A culture that insists of doing everything "the French way" by actively swimming against the stream of common sense, from speaking French to ATC, to having checklists and call outs in French and making an LP6 in French more important than an LP6 in English?
Could that perhaps be the real problem here? A problem that has been discussed here on PPRuNe for many many years, and a problem that any non-French pilot can easily identify after just a few flights to France?
Join Date: Jan 2008
Location: Europe
Posts: 135
Likes: 0
Received 0 Likes
on
0 Posts
I'm not going into details, but you are totally out of line. You obviously have no clue about what's going on here and the way we work.
Considering the number of incidents, ATC watcher wrote an excellent post about that. Do you really think that nothing happens in, say, the ME3, or some famous european LCC? Of course, they never show up on avherald, but try to guess why.
As for arrogance, I will let the reader guess who is being arrogant here, and who is feeling superior.
Considering the number of incidents, ATC watcher wrote an excellent post about that. Do you really think that nothing happens in, say, the ME3, or some famous european LCC? Of course, they never show up on avherald, but try to guess why.
As for arrogance, I will let the reader guess who is being arrogant here, and who is feeling superior.
Join Date: Feb 2006
Location: next to sidestick
Posts: 481
Likes: 0
Received 0 Likes
on
0 Posts
Could it also be that perhaps the real problem is not really the safety culture, but rather an extremely arrogant superiority complex culture, also known as French chauvinism? An inbred culture that is not open for change?
And FYI I believe procedures are now done in English in AF, at least on the airbus fleet. Maybe an AF pilot could confirm, but I doubt any would be reading this topic - probably gave up reading and disgusted by all the drivel on here about the french this and the french that... Listen to yourselves for christ sake
I am not saying that the french are perfect, but all cultures have their own peculiarities. I could easily have a go at the Dutch or the spanish or Italians, and certainly the brits, but I won't. They all have bad sides, but that doesn't make them, as a whole, bad pilots, as some here seem to suggest about the french.
Serious incidents occur in most airlines, especially in large ones such as AF, and even in some airlines that portray themselves as the best in terms of safety. The fact that those incidents don't make it into the open doesn't mean they don't occur, only that they are kept under wraps. How's that supposed to improve safety?
