Can any of you tell me if you do your performance calcs 100% independNtly from your offsider? On a different iPad/tablet/scratchpad etc ?

Strut pressures
 

KenV:


OK .. back to civility .. sorry if I bit a touch hard.


Are there no pressure transducers in the struts now?
I'd have imagined that strut pressure would be a logical parameter to monitor other than for load weigh reasons.
How does WOW work on later aircraft? Surely not still through squat switches.

Landing gear are complex and the load paths more so. It is hard to know exactly which paths all the loads take under all conditions, making consistently measuring those loads difficult, especially when the ground is not perfectly level/smooth and/or there are high winds/wind gusts.

The squat switches have been replaced by prox switches, but otherwise, yes, it's still done like it was decades ago.

Framer- EK now do independent calculations. The procedure is almost identical to what you described you use.

"especially when the ground is not perfectly level/smooth and/or there are high winds/wind gusts."

Ken - you are of course correct if you are looking for absolute accuracy but what is needed is something to catch the really bad mistakes - the factor of 2 or 10 - not a super correct engineering solution correct to 100kg

Some sort of averaging should work fine

You are correct, it all depends on what you want the system to do. If all you want to do is catch a big mistake, a simple system will do. But such a system will be wrong almost all the time. And any system that is wrong almost all the time will be ignored, defeating its intended purpose.

Hardly. You have three, four or five legs, each with an oleo pressure. Its not rocket science to deduce a weight and balance from that.

And you could always zero the weight on a turnaround, when the aircraft was empty. The system knows the fuel weight, so can give you a 'lowest turnaround weight', and you just click 'yes' if the aircraft was empty on that turnaround.

Jezz, if the venerable old Belslow frieghter could have an automatic weight and balance check system, I am sure a modern airliner could. We appear to be going backwards, not forwards. As usual, it all comes down to cost.

LOTS of loads go through the drag links and cross links and not just through the oleos, especially on non level or uneven surfaces, . Second there is significant stiction (static friction) inside the oleos. The oleos do NOT behave linearly. Measuring the oleo pressure gives a gross approximation, not an accurate weight.

As for cost being the driver, no, that is not true. Yes, it is a significant influence, but NOT the driver. An automatic weighing system would be a god send in a military freighter that operates from austere airfields. Neither the C-130 or C-17 have an automatic weighing system because they are simply not reliable enough. I cannot confirm it, but I'm pretty sure the A400 does not have one either.

"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.

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."

JUST THOUGHT I'D REPEAT WHAT I SAID IN POSTING #4, before the discussion descended into a foreigner-bashing session. Proof positive of how easily we all get distracted?? :ugh:

Yip. I agree , especially if emphasis is put on the importance of the calculations being made independently with a comparison only occurring once the final result is at hand.
Also, often times now days the ground staff are on minimum wage, minimum training, maximum workload ( turning more aircraft than they used to) and have no idea that distraction on the flight deck during this phase can be lethal so it is up to the pilots to enforce this sterile flight deck environment if the cabin crew don't. It is another example of how safety is slightly reduced each time an accountant has another brilliant idea about " lean operations" and implements it with no real understanding of what makes airline flying safe. I am all for efficiency and working hard but we are reaching a point where our enviable industry safety record will be tarnished on a regular basis if we don't act ( read spend money) when our SMS 's start squawking.

WHAT IF...
 

What if the French took to heart what everyone else is just bragging about. They actually REPORT the mistakes and incidents that happen. BEA even releases a little paper on reported mistakes and incidents from time to time.

So what if this thread exists just because AF learned from AF447 and since then started the reporting trend...?

I am 100% sure that if regulators in other countries was as efficient in getting reports, we all would feel a little scared. Some LCCs spring to mind. I know one where a CC fell out of an open door and right onto the tarmac. Now that's what fairy tales are made of.

So, may the odds be ever in your favour.

Quote...
And you could always zero the weight on a turnaround, when the aircraft was empty. The system knows the fuel weight, so can give you a 'lowest turnaround weight', and you just click 'yes' if the aircraft was empty on that turnaround.


I think you need to re-define 'Empty'.... The galley will always have some food and water, the tanks will not be dry, and there may be hidden engineers lurking in the recesses.

Don't some models of the B747 freighter have a self weighing system as an option ?

Thats interesting Stilton. Can anyone give us more information about self weighing systems. Are they precise? Are they reliable? How often do they need maintenance and could they be zeroed during turn around even if Engineers are aboard? Also, has a system like this ever been fitted to an earth moving truck?

Several folk have asked whether there's an independent check with the other pilot, to which the answer should always be yes. Of course it's never COMPLETELY independent; both calculations rely on the same load sheet. Yes they are quite often wrong. But for some reason this never makes headlines the way a mistake by a pilot does, and the dispatcher who used to be a key person capable of filtering some of these mistakes is now likely to be a min-wage school leaver. Also, electronic loadsheets are calculated to a spurious accuracy which makes a gross error less likely to stand out. For instance the trim setting may be given as 45.92 even though the trim can only be set to whole numbers

HUMAN FACTORS
 

Errors like the 100 ton mistake, the ZeroFuel Mass into Gross Mass input boxes, etcetera, are HUMAN FACTOR errors.

Wire somebody up for a brain scan of some sort and show him a picture of any kind of snake - his brain will show signs of ALARM all over the place.

Show him a picture of a sort of keyboard or piece of paper with numbers on it - his brain may show some activity in regions connected to arithmatic processes or text interpretation processes, but there will be NO TRIGGER OF ALARMS AT ALL.

Mankind is conditioned through millions of years to the danger of snakes, or lions, or other DANGEROUS creatures of nature and INSTICS will cause us to err on the safe side in case of doubt - oh, it was only a piece of black electric wire ....

Mankind invented typing , computers, keyboards, etcetera less than a century ago and even though a simple typing error of one wrong digit can bite you in a deadly fashion, our instincts have not yet adapted to that sort of monsters ...

First, man has to realise the deadly danger of errors in the complete process surrounding T/O performance and then he has to stick religiously to procedures that must ascertain independent calculations of which the results must be compared.

Addition of more automatic bells and whistles is not the magical pill to stop the errors from occurring.

Awareness of the danger and discipline in execution of correct procedures are the key.

And yes, in the big world with many different companies, improvement of procedures or layout of information may be necessary to be able to speak of "correct procedures".

Sorry, chum, but the galley, water and crew are all included in the empty weight, while the FMC knows the fuel amount and the nominal empty weight (APS weight). And if you think that a few engineers and loaders are going prevent the system from spotting an error of several tonnes, you need to send your engineers on a fitness course.

Meanwhile, KenV's absurd suggestion that the oleo torque links take the weight of the aircraft must take the 'aircraft anorak gibberish' award for 2015. Thanks, KenV, you have just confirmed that the closest you have got to an aircraft are the models on your mother's dressing table.

The whole self-weighing argument is a little bit of a red herring since weight (ok, mass, if you're being picky) is only one of a number of factors which could produce erroneous take-off data.

All attempts to make an airplane pilot proof failed so far.

So have all attempts to make the perfect pilotless airplane...