back to article Data entry REAR-END SNAFU: Weighty ballsup leads to plane take-off flap

We're all accustomed to tales of woe that children are becoming too fat, but how about too-light kiddies spoiling the balance of an aircraft? An error at Australia's Canberra airport left a 168-seat Boeing 737 struggling to take off because a group of 87 schoolchildren was entered into the check-in system as adults. As noted …

  1. json

    As the saying goes..

    ...a nose heavy plane flies poorly, a tail heavy plane flies once.

    1. Anonymous Coward
      Anonymous Coward

      Makes a change from blaming fat people....

      1. Destroy All Monsters Silver badge

        .... they were all in the front seats, munching the donuts meant for the children.

  2. Dave Bell

    There is nothing new in this, other than how the miscalculation happened. And I wouldm't like to bet on historical assumed weights being all that reliable today. Could they put an automatic weighing machine under the passengers queuing for that security check?

    1. Anonymous IV

      Wouldn't weighing them infringe the passengers' Human Rights?

      And, most importantly for the check-in staff, Why Didn't They Think Of The Children?

    2. Ledswinger Silver badge

      " Could they put an automatic weighing machine under the passengers queuing for that security check?"

      Good idea. And then combine the baggage and passenger weight allowance to make everything fair.

      1. tony2heads
        Thumb Down

        @ Ledswinger

        I would have a severely negative baggage allowance

        However if I were running an airline I would split up any group of children so that no two sit next to each other; I remember how some boys would always misbehave at the back of the bus on any school trips.

      2. Anonymous Coward
        Anonymous Coward

        Not fair

        ...But then Americans wouldn't be able to afford to fly anywhere...

    3. Raumkraut

      > Could they put an automatic weighing machine under the passengers queuing for that security check?

      Rather than the error-prone process of getting ignorant passengers to cooperate with ignorant airport staff and poorly-designed/maintained boarding equipment, I would have thought that some kind of sensor on the front landing gear's suspension would quite easily be able to determine whether the plane was overly front-heavy/light?

      1. Cliff

        >> I would have thought that some kind of sensor on the front landing gear's suspension would quite easily be able to determine whether the plane was overly front-heavy/light?<<

        I'd been thinking about this myself, and the three points of static, standing contact with the ground really ought to be able to triangulate loads and balance/centre of mass. In fact this is so important to get right, I'm stunned they're not already doing this.

        1. roytrubshaw

          The Pendolino trains (Pendolini?) seem to have it. (Sensors attached to the suspension system, I mean.) I have - at least once - been on a train where the driver has refused to continue because one car (out of nine at the time) was overloaded. The train manager informed me that there was no point in him even trying as the software would apply the brakes almost immediately should he attempt to move the train in an 'unsafe' configuration.

          My point is that if they can apply it to a nineteenth century form of transport why not the following century too?

        2. phil dude

          tare weight...

          A pilot had told me that is what they actually do (strain gauge on wheels) - at least for commuter planes. In the USA I have had to "move to balance the plane" more than once, so I imagine the weight of the plane is not an unknown parameter!!!

          Must be something else going on...

          P.

          1. Nigel 11

            Re: tare weight...

            Commuter flight. The smaller the plane, the more easily it can be unbalanced. One twenty-stone passenger at one end and two small children at the other are a significant imbalance, if the plane seats twenty rather than two hundred.

            In passing, this is the real reason they'll upgrade economy class passengers to business-class if business-class isn't anywhere near full. A tail-heavy plane is unsafe. Passengers in business class are a necessity for safe operation!

        3. Vic

          I'm stunned they're not already doing this.

          It was first introduced on the Boeing 707. Airbus also have a similar system.

          I'm told it's not that useful on account of wind blowing over some large aerofoil surfaces attached to the fuselage...

          Airbus aircraft can measure the performance in flight and determine aircraft loading that way.

          Vic.

        4. Lars Silver badge

          "In fact this is so important to get right, I'm stunned they're not already doing this." In that industry there always has to be a big accident before anything will change.

        5. dubious

          Pretty sure I read about strain sensors in the landing gear to measure weight 30 years ago in a Richard Scarry book.

          Now, I'll concede that it probably wasn't the last word in aeronautical textbooks, but one assumes he did some research!

      2. Brian O'Byrne

        There is one problem with that approach: the test is very late in the process.

        Pilots and crews are busy enough in the final few minutes before takeoff. You are talking about adding another technical check at that busy time.

        If there is a problem detected what should they do? You need more procedures and to determine how to correct the weight distribution and the co-operation of the passengers.

        The existing procedures should work. They failed in this case because there was a problem at checkin: the children were checked in as adults. Adding another test at that time would be much more cost-effective than adding a test minutes before pushback.

        1. Jason Bloomberg Silver badge

          All systems go for take-off

          Pilots and crews are busy enough in the final few minutes before takeoff. You are talking about adding another technical check at that busy time.

          I would rather they do that check before they trundle down the runway and find themselves up shit creek during take-off. It shouldn't be an overly onerous or time consuming check; probably just checking whether the "out of kilter" light is red or green. It's not like we are asking pilots to do something pointless. And lives are at stake, including the pilots' own.

        2. Nigel 11

          If there is a problem detected what should they do? You need more procedures and to determine how to correct the weight distribution and the co-operation of the passengers.

          This is the sort of thing that the plane's computer should do. Check the loading. Do nothing if it's within optimal operating parameters. Alert the crew if it's sub-optimal, so that they are forewarned and can decide whether other conditions (bad weather etc.) make it necessary cancel the take-off. And refuse the allow the plane to fly, whatever the crew might think, if it's so badly ourt of balance that attempting take-off is likely to be disastrous.

          So the flight crew would get an orange light maybe one flight in twenty, and a red light once in a blue moon, and air travel would become slightly safer. What to tell the passengers if it's a red light? That the plane is unable to fly because of a red light that has to be investigated. If the problem is in the passenger distribution, that should be obvious to the flight attendants once they are told to look. I expect more often, it's in the cargo hold.

          Not having any instrumentation so the problem can't be detected until the plane is halfway down the runway, is crazy. That may well be too late. One of these days, just when the pilot needs more thrust than usual, there will be an engine failure. Most disasters happen because too many things go wrong at once, not because just one thing fails.

          1. Vic

            This is the sort of thing that the plane's computer should do

            No, absolutely not.

            De-skilling the pilot's job is what leads to accidents - Air France has several crashes that are entirely because the pilot(s) decided to put all their trust in the computers (and then failed to jnotice that the computer was telling them not to).

            Weights and balances calculations are a simple operation; all that's needed is for the check-in staff to *check* their passengers in properly.

            Not having any instrumentation so the problem can't be detected until the plane is halfway down the runway, is crazy. That may well be too late

            It isn't too late. The take-off procedure allows for this sort of error, and will leave the pilot plenty of room to abort the take-off if the aircraft cannot be flown. Aircraft designers aren't *all* idiots...

            Vic.

            1. Nigel 11

              Computers

              Having a computer take over as many of the boring pre-flight checks as it has instrumentation to perform is likely to increase safety. A computer will do the same thing over and over again with almost 100% reliability. It won't ever get bored or distracted. Humans aren't like that. They tend to miss items from long checklists, and sometimes miss even a red flag if they're bored.

              I agree about actually flying the plane, and the handling of critical situations in the air. In these cases, an experienced pilot's instincts are likely to work better than a computer following a completely fixed rule-set. It's a completely different situation to running through a checklist.

              1. Vic

                Re: Computers

                Having a computer take over as many of the boring pre-flight checks as it has instrumentation to perform is likely to increase safety. A computer will do the same thing over and over again with almost 100% reliability.

                I disagree. The computer will only process the data it is given - so it won't be able to do the sanity checks that a pilot can, because the pilot has additional information (e.g. he can stand at the door and watch the SLC do its stuff). The computer just doesn't have that data - so if there is an error of data entry, it is likely to go unnoticed. This can only reduce flight safety.

                I agree about actually flying the plane

                The nen-route section of the flight is the one place I am perfectly happy for the computers to do the work - as long as the pilots keep an effective watch and have the option to switch off the AP.

                Vic.

    4. petur
      Stop

      "Could they put an automatic weighing machine under the passengers queuing for that security check?"

      I fail to see how this would work with the current reservation system that most airlines have, where you can pick your seat yourself.

      At best, it would flag imbalance and cause seat reassignments shortly before departure (ie, chaos)

      1. Adam 1 Silver badge

        >At best, it would flag imbalance and cause seat reassignments shortly before departure (ie, chaos)

        If only they were carrying hundreds of tonnes of some sort of liquid that could be pumped into tanks in different parts of the aircraft to rebalance the weight.

        1. Nigel 11

          If only they were carrying hundreds of tonnes of some sort of liquid that could be pumped into tanks in different parts of the aircraft to rebalance the weight.

          Irony?

          The obvious problem with redistributing the fuel prior to take-off, is that for a flight destination close to the plane's maximum range, the tanks will all be close to full. Take-off and climbing to cruising altitude uses a significant fraction of the plane's fuel, after which optimally balancing the plane during the rest of the flight is part of normal operations.

          And of course, you would need to have instrumentation on the plane's undercarriage to detect the loading problem. Halfway down the runway is too late to rebalance the fuel load.

        2. Pookietoo

          re: hundreds of tonnes of some sort of liquid

          They dispose of much of that liquid before they arrive at their destination, and landing is a somewhat delicate procedure too.

    5. Anonymous Coward
      Anonymous Coward

      "Could they put an automatic weighing machine under the passengers queuing for that security check?"

      Make the plane docking station incorporate a weighing bridge. With several sensors they could also determine the weight distribution. Doesn't have to be mechanical. They could user lasers to determine how much the ground sinks - and they would know the plane's unloaded weight as a calibration check each time.

      1. Jaybus

        Weighing aircraft

        Yes, it is far easier and safer to integrate scales into the gate/docking station. No, it would not need to use lasers. The K.I.S.S principle always applies with aircraft procedures. Heavy duty truck scales should suffice. Obviously, these aircraft do not require extremely precise weight distribution measurements. Plus or minus 10% is likely good enough. This would also be far cheaper than retrofitting sensor systems into existing aircraft. The problem is, it shifts the cost from airlines to airports, and the airports will balk at the extra cost.

    6. Phil O'Sophical Silver badge

      Could they put an automatic weighing machine under the passengers queuing for that security check?

      They do on flights with tiny planes, checking in for an Aer Arann flight to the Aran islands (6 passengers + pilot) we were all weighed with our hand luggage, and then told where to sit.

    7. Version 1.0 Silver badge

      Weigh the customers

      I flew several flights on an airline with small (10-12 seats) planes in Costa Rica about 15 years ago and they weighed everyone and assigned seats based on each passengers weight. The only people who complained were American.

      1. Michael H.F. Wilkinson Silver badge
        Joke

        Re: Weigh the customers

        Were these Americans perhaps asked to sit on the wings? That might explain it

    8. yoganmahew

      Weights are up in the last fifteen years or so, adults used to be calculated at between 65 and 70 kilos, with kids at 35.

      There are trim wheels on planes, but I believe pilots are under instructions to accept the trim settings from the loadsheet. IANAP either, though...

      Right, over to pprune...

  3. T. F. M. Reader Silver badge

    Insurance?

    A single group of 87 schoolchildren and 9 adults from the same organization on the same plane? Were there any special insurance arrangements? Just wondering...

    1. Destroy All Monsters Silver badge
      Paris Hilton

      Re: Insurance?

      Why? It's not like these are key personnel for ${ORGANIZATION}

    2. Fonant

      Re: Insurance?

      I bet they all went into the same bus/coach to get to the airport. Much more likely to be all killed in a coach crash than a plane crash. Insurers are much more likely to worry about the costs of flight delays, or the children getting ill abroad, than the minuscule likelihood that a plane would crash.

  4. frank ly Silver badge

    the “adult weight” of 87kg

    I weigh 68kg (I'm 5'10" so my BMI is about 22) and regard myself as 'normal'. Am I actually 'skinny'?

    1. Red Bren

      Re: the “adult weight” of 87kg

      You read El Reg, you're definitely not normal!

    2. John H Woods Silver badge

      Re: the “adult weight” of 87kg

      At 1.78m and 68kg I think you're slimmer than average if you're male. You're the same height as me though ... anecdote:

      My Doctor: "You are 15 Stone. Do you know your BMI?"

      Me: "Of course, it's exactly twice my weight in Stone, 30"

      Dr: "That's not how you calculate it"

      Me: "It is if you are 5 foot 10"

      Dr: *fiddles with calculator, then laughs* "do you spend a lot of time sitting around thinking about maths?"

      Me: "Why do you think I'm so fat?"

    3. Alan Brown Silver badge

      Re: the “adult weight” of 87kg

      yes you are - but they allow 15kg for hand baggage, despite what the posted limits are. Passengers always overstuff the things.

      1. Nigel 11

        Re: the “adult weight” of 87kg

        Unless it's a RyanAir flight, where they fine you something silly for every extra ounce.

  5. Destroy All Monsters Silver badge
    Paris Hilton

    Speaking of which, it has gone awfully quiet around MH-17?

    1. Ledswinger Silver badge

      Provisional report's due out in a day or two, IIRC. Hopefully the report will be technical and of high quality (as most air accident investigations are), but the public voice of Western powers will be much as before - airliner shot down by advanced SAM, don't really know who fired it, it crashed in separatist held territory, so it MUST be the separatists. In the same way that because Pan Am 103 crashed in Scotland, it had to be the fault of the SNP.

      1. Destroy All Monsters Silver badge

        Here's hoping that this won't be used to inflame the situation further.

        Fat chance, I know.

        1. Anonymous Coward
          Anonymous Coward

          Does it really matter who shot it down?

          It was obviously a mistake, whoever did it. And there were no dreadful consequences when the USA accidentally shot down an Iranian passenger flight. I suppose we could politely ask everyone who might have done it to issue a conditional apology without admitting responsibility? It's funny how the media always seem to concentrate on some trivial aspect of a serious situation, like an amateur beheading, for example.

          1. Alan Brown Silver badge

            Re: Does it really matter who shot it down?

            "And there were no dreadful consequences when the USA accidentally shot down an Iranian passenger flight"

            The USA stepped up right from the outset and said "oops". The people involved were disciplined and payouts were made.

            Compare and contrast to what's happened in Ukraine so far.

            1. Ledswinger Silver badge

              Re: @Alan Brown

              "The USA stepped up right from the outset and said "oops". The people involved were disciplined and payouts were made."

              Err, they had to be dragged to the international courts to pay up.

              And not only did the US award the crew combat ribbons for their performance in the gulf, the Vincennes air warfare coordinator received the USN Navy Commendation Medal, and later the commander of the Vincennes was awarded the Legion of Merit medal for his command of the ship.

            2. Vic

              Re: Does it really matter who shot it down?

              The USA stepped up right from the outset and said "oops". The people involved were disciplined and payouts were made.

              The USA refused to apologise. They made an ex-gratia payment, but did not admit or accept liability.

              Vic.

          2. Ledswinger Silver badge

            Re: Does it really matter who shot it down?

            "It was obviously a mistake, whoever did it. "

            What makes you say that? The alleged attack weapon was an advanced weapon capable of reaching high altitude that required multiple crew members, and two or three different ground vehicles. Whoever fired it and was able to hit a target flying six miles up at nearly 500 miles an hour miles up knew exactly what they were doing with complex anti-aircraft weaponry, and by definition would have known that civilian air traffic was operating in the area at that altitude, would have been able to deduce that this was civilian (from speed, altitude and course) and therefore knew this wasn't either a Russian air force intrusion, nor a Kiev military transport landing supplies.

            Putin was on a plane through this airspace 200 miles (ie 24 minutes) behind MH17, and if you accept my suggestion that whoever launched the missile knew exactly what they were unleashing, then there are only a couple of obvious conclusions, both of which are fairly unpleasant:

            1) This was an attempt to assassinate the leader of the world no.2 nuke weapon power (with more important questions than who launched the missile, like who originated the scheme, and who authorised it).

            2) The Putin proximity was irrelevant, and the intention was to deliberately bring down any passing commercial transport, intending to implicate the other side (a false flag attack). I'd not be so bold as to suggest this proves anything, but the immediate enthusiasm of Western power to blame Russia first and separatists second is notable.

            There is perhaps a third option, the "Vincennes excuse", in which those who launched the missile intended to bring the plane down, but in the red mist they'd ignored the obvious signs that this was a non-combatant, but that's like claiming that murdering the wrong man is only manslaughter, and doesn't wash for me.

            1. Jason Bloomberg Silver badge

              Re: Does it really matter who shot it down?

              Whoever fired it and was able to hit a target flying six miles up at nearly 500 miles an hour miles up knew exactly what they were doing with complex anti-aircraft weaponry...

              Or perhaps saw the "target acquired" light come on and simply hit the launch button, whooped with delight until they realised what they had brought about.

              The transcript which puts the blame on the rebels even has them talking of shooting down an enemy plane and I can well believe that's exactly what they thought they'd done and intended to do. A simple repeat of bringing down a Ukrainian transporter as they'd already done earlier.

              There was nothing to be gained by rebels deliberately shooting down a civilian airliner and everything to lose so I cannot believe it was intended if the rebels did bring it down.

              1. Ledswinger Silver badge

                Re: Does it really matter who shot it down?

                "The transcript which puts the blame on the rebels even has them talking of shooting down an enemy plane and I can well believe that's exactly what they thought they'd done and intended to do. "

                It could be true, but I think its a bit odd that military personnel capable of operating advanced defence electronics would be speaking in the open on insecure telephone lines, don't you? The veracity of that transcription has yet to be proven.

                "A simple repeat of bringing down a Ukrainian transporter as they'd already done earlier."

                Very different. The transport was at lower level, and believed to be brought down by a man-portable device incapable of reaching the altitudes at which civilian airlines were operating. A MANPAD involves far less skill (and thus implies less knowledge and awareness of the user), and has far more limited range, so couldn't shoot down MH17.

                1. Franklin

                  Re: Does it really matter who shot it down?

                  "It could be true, but I think its a bit odd that military personnel capable of operating advanced defence electronics would be speaking in the open on insecure telephone lines, don't you?"

                  My father was career military. No, I don't find that one bit odd. Technically skilled specialists talking in the open on insecure telephone lines is *far* from surprising.

                  1. Anonymous Coward
                    Anonymous Coward

                    Re: Does it really matter who shot it down?

                    During an unnamed ecunnamewargame in an unnamed country, with troops from 2 different unnamdd countries participating, the more technologically advanced party scanned and jammed the other's military frequencies, resukting in fixed lkne and motorbike messenger being onky working form of 'classical' communication.

                    The commander of the technologically inferior party, at a key moment when the enemy was about to waltz right through his now disorganized line, picked up his civilian private cellphone, called directory service and set up conference call between himself, his spotters, and his artillery, and completely surprised the advancing party.

                    These were 2 western armies, btw...

            2. Red Bren

              Re: Does it really matter who shot it down?

              "Putin was on a plane through this airspace 200 miles (ie 24 minutes) behind MH17"

              Would anyone care to remind the class the colours of the Russian flag and the colour scheme of a Malaysian Airlines aircraft?

              1. Red Bren

                Spot the difference

                http://en.m.wikipedia.org/wiki/Malaysia_Airlines_fleet#/image/File:Malaysia.airlines.b747-400.9m-mph.arp.jpg

                http://en.m.wikipedia.org/wiki/Russian_presidential_aircraft#/image/File:Il96-300pu-96016.jpg

            3. Nigel 11

              Re: Does it really matter who shot it down?

              but that's like claiming that murdering the wrong man is only manslaughter, and doesn't wash for me.

              In a war, that's not manslaughter, it's not even regarded as a crime. It's "collateral damage" provided one's intent was to hit the enemy, and the poor bloody civilians were just in the wrong place at the wrong time.

              War sucks.

              And so do conspiracy theories. Until there is hard evidence, I won't be attributing to malice(*) that which is adequately explained by incompetence.

              (*) malice by the hapless incompetents in charge of the missiles, that is. Putin does have a lot to answer for, in terms of creating and prolonging the war, and in terms of putting those missiles in the hands of inadequately trained rebels.

            4. Vladimir Plouzhnikov

              Re: Does it really matter who shot it down?

              1) This was an attempt to assassinate the leader of the world no.2 nuke weapon power...

              2) ... the intention was to deliberately bring down any passing commercial transport, intending to implicate the other side (a false flag attack).

              There is perhaps a third option, the "Vincennes excuse", in which those who launched the missile intended to bring the plane down, but in the red mist they'd ignored the obvious signs that this was a non-combatant

              I would rate the probabilities as 90% option 3 (screw up), 9.9% option 2 (false flag) and about 0.1% option 1 (shootin' Putin)

              There is a possibility of a mixed option 3 and 2 - when the missile was fired by the separatists but based on "injected intelligence" - I would quantify it as 20%-30% (within the above 90%).

              I say this because it is easy to hit a wrong target by mistake when operating a SAM like Buk.

              The crew tracking a target sees primarily the bearing, range and elevation data on 2 or 3 separate indicators. They don't see the altitude directly. There normally is an optical tracker with a nice telephoto lens and IR capability but it's use in an engagement is optional, it is visible to only one crew member, its probably BW and if there is a cloud cover there is not much use in it anyway.

              They also have an IFF interrogator but I'm not sure that it would have picked-up a civilian transponder response and the normal SOP will be for the crew to use it manually a couple of times before launching the missile. I am pretty confident that the separatists crew (if it was them) would have ignored the IFF because they would have expected any target to be hostile (they had no "friendly" A/C) and without agreed codes the IFF is useless anyway.

              So, a mistake would have been easy to make - but precisely because of that they should have taken a lot of extra care and they clearly hadn't.

  6. Anonymous Coward
    Anonymous Coward

    Next up: flying in circles

    What would happen if they were all sitting on one side? :)

    As IANAP* I'm confused by this, though - the only thing I can see fail is weight (and thus fuel) calculations, I can't see how they would have much influence on who sits where. Cheap carriers like *barf* Ryanair and Easyjet don't even *have* seat allocation, so how do they cope?

    (*) I am not a pilot

    1. S4qFBxkFFg

      Re: Next up: flying in circles

      It's due to centre of gravity issues.

      It's more complicated than I will/can explain, but the greater the distance the CofG is from the tail, the more torque will be generated by aerodynamic effects on the tailplane/elevator (and fin/rudder).

      Roughly speaking, the further forward the CofG, the more stable it will be (like a dart) and vice versa.

      In extreme cases of instability the aircraft may be uncontrollable; if it's too stable, the pilot may be unable to flare (pitch up) on landing, causing a harder impact and/or bounce.

      1. Alan Brown Silver badge

        Re: Next up: flying in circles

        "Roughly speaking, the further forward the CofG, the more stable it will be (like a dart) and vice versa."

        Part of training is to fly circuits in a tail-heavy plane. It's BLOODY HARD WORK - when I was practising in a cessna 172 I initially didn't have enough physical strength to keep the stick pushed forward and was considering using a foot. It's still the single most scary experience I've had whilst in the front seat.

    2. Anonymous Coward
      Anonymous Coward

      Re: Next up: flying in circles

      Non-allocated seating tends to be chaotic (in the technical sense - appears random but has certain patterns), therefore tends to even itself out.

      A large group like this messes up that pattern.

      Also, it's not just weight/fuel, it's handling characteristics - if you've driven a car with a heavy load in the back, you know the difference it makes and you have to adjust your driving accordingly. Planes are move sensitive to that sort of thing due to the 3D nature of flying through air (rather than a 2D road). The problem here is that at take-off, the pilot was expecting one thing and got another. Take off and landing are the most dangerous parts of flying, so having surprises is not good!

    3. rh587

      Re: Next up: flying in circles

      As S4qFBxkFFg says, it's to do with balance and Centre of Gravity. Too much weight up front and you can't take off, too much down the back and you take off, nose up, stall and crash as that 747 did in Afghanistan when the load shifted to the rear during take off.

      That's why they weigh your baggage - not just for compliance with your allowance but so they can load the hold crates appropriately so heavy bags are distributed along the length of the aircraft, not all bunched up at one end.

      For EasyJet and RyanAir, they're working on the premise that all things being equal, the passenger distribution will be about equal, and many of their aircraft are only 100 seats anyway, so a group that large would in itself equally distribute down the cabin! However, on a big several-hundred seat aircraft with allocated seats where they will be bunched together, groups may need breaking up, putting in the middle or counter-balancing with another similar group at the other end.

      1. Cliff

        Re: Next up: flying in circles

        As for your question about all sitting on one side of the plane - planes are long and thin, the effect of the mass varies with distance from the rotational centre (its moment), so yes, chunky people do have an effect if they're on the right side of the plane and the malnourished on the left side - but as we're talking a few feet as opposed to tens of yards, the effect is less pronounced and easily 'trimmed' for.

      2. Holtsmark

        Re: Next up: flying in circles

        For this reason (I believe) Ryanair also blocks the front and rear rows in flights that are not fully booked.

        This results in the variable passenger weight distribution being clumped up arount the centre of gravity, where they can not do too much damage. Reasonably clever thinking.

        1. FixitPerson
          Go

          Re: Next up: flying in circles

          Last time I flew on a Ryanair flight which wasn't full some fellow passengers asked if they could sit in the blocked seats. The cabin crew politely responded with sorry, but no, because of aircraft balance. Cue the next question from one passenger: fine, but can we sit there after the plane takes off!

          On that flight it was the rows near the middle (over wing, centre of gravity) which were blocked.

    4. G.Y.

      old EE Q Re: Next up: flying in circles

      Why did the Warsaw flight crash?

      All the poles were in the left half-plane

      1. Andy Taylor

        Re: old EE Q Next up: flying in circles

        Why did the Warsaw flight crash?

        All the poles were in the left half-plane

        <pedant>

        Shouldn't that be in the right half? Left half poles = stable system.

        </pendant>

        1. John H Woods Silver badge

          Why the Warsaw flight crashed...

          I heard the joke as follows:

          The pilot was just a simple Pole in a complex plane - so they used the method of steepest descents.

    5. bitmap animal

      Re: Next up: flying in circles

      To expand on what S4qFBxkFFg said, the window seats are not that from from the CoG so have a small effect. The front & rear seats are further away so have more of an affect on the balance. Get a bucket full of water and hold it by your side, then hold it out to the side at arms length and feel the difference.

      I was also going to mention that cargo 747 when the load shifted, that is slightly different though at it happened during flight and so the balance changed.

      There are also instances of planes tipping up on the ground. The VC10 stored fuel in the tail fin and if that was emptied last the plane did a wheelie.

      http://www.vc10.net/History/Images/XR806_writeoff.jpg

      You would have a similar problem if they loaded a couple of catwalk models in first class at the front then the entire World's Strongest Man competitors at the back.

      1. graeme leggett

        Re: Next up: flying in circles

        from same website http://www.vc10.net/History/incidents_and_accidents.html#XR806 Brize Norton 18 December 1997

        interview without coffee for culprit(s)?

    6. Naughtyhorse

      Re: YA-clearly-NAP

      Balance.

      the main difference between driving, sailing and flying is that there is progressively less and less drag, this requires more and more forward planning. planning on having a big lump of grown-ups in the back that turn out to be sprogs changes the balance, then all bets are off!

  7. Anonymous Coward
    Alert

    Call to all passengers

    Do we have any real lard arses on the plane who can still walk?

    If so please make yourself known to the ballast steward.

  8. streeeeetch

    Weigh the bloody thing

    Why do they need estimates? Put temperature and pressure sensors in the wheels and sample them once a minute or so. Should give you weight, distribution and leak (and are my tyres on fire!) info. Don't they do this already?

    1. Thesheep

      Re: Weigh the bloody thing

      I guess any such devices would need to be robust enough to stand the considerable load during landing, though...

    2. Gideon 1

      Re: Weigh the bloody thing

      Much simpler: A strain gauge (resistor printed on a piece of sticky film, responds to stretch or compression) on the landing gear strut will measure its load.

  9. This post has been deleted by its author

  10. A Non e-mouse Silver badge

    Adults Vs Children

    This isn't as easy as people think.

    When I was at school, a group of us went on a skiing trip. Most of us sixth form boys were bigger than the teachers. (No, it wasn't because we were fat, lazy, lard-arses, either) Plus there were more sixth formers than teachers.

    But according to the rules, we were classed as children and the teachers as adults. I imagine that made the plane's weight calculations interesting...

  11. squigbobble

    "That meant the pilot had to get the jet into the air without scraping the tail on the runway."

    As other people have implied, this is exactly the opposite of what the pilot would be facing- not being able to get the nose up leading to the aircraft charging down the runway at 200mph.

    1. Stu J

      Re: "That meant the pilot had to get the jet into the air without scraping the tail on the runway."

      If you read the report, the pilot had to apply a lot of force to get the nose up - however he was conscious about applying too much force, at which point there may have been a tail strike.

      It's easy to have fine motor control when you're doing things well within your physical capabilities, but as you get towards the edge of your comfort zone, your accuracy will be diminished.

      Most weightlifters will be able to lift lighter weights with very good form, controlling all the way up and down; you get up to maximum weight, and the form becomes far shakier, less accurate, and forget about controlling on the way down altogether.

      I'm not sure how much force will have been needed, but if it's "abnormal" then you're into the unknown as far as the aircraft's performance is concerned.

      1. Vic

        Re: "That meant the pilot had to get the jet into the air without scraping the tail on the runway."

        It's easy to have fine motor control when you're doing things well within your physical capabilities, but as you get towards the edge of your comfort zone, your accuracy will be diminished.

        He was flying a 737 - it's got dual hydraulic controls. He would have been aware of the elevator being heavier than normal, but it's nowhere near the limit of his ability to pull the column, unless he is extremely infirm...

        Vic.

  12. karma mechanic

    Measuring the weight distribution on the tarmac

    Three points should make it easy.

    Except that any amount of wind is going to alter the readings considerably. Turbulent wind like you'd get near the airport buildings would probably give wildly oscillating readings, and a steady wind would give significant amounts of lift and/or other pressures over the tail.

    Assuming you have control over where the fuel and hold baggage is then you could have seat sensors that can distinguish between empty, child, adult and lard-arse, and work out from that whether anything has gone awry. At great expense.

  13. Anonymous Coward
    Anonymous Coward

    Why didn't they all just jump in the air just before takeoff...

    and thereby reduce the extra load on the aircraft to zero....

  14. JaitcH
    Unhappy

    Wouldn't happen in the States ...

    so many kids look like mini-Michelin men from all the McBarfs and other super-sized and saturated fat products they eat.

    1. Queasy Rider

      Re: Wouldn't happen in the States ...

      "over-estimated the weight of the plane by between 3.5 and 5 tonnes," had me doing the math. 5,000 kg / 87 kids = 57 kg. 87kg -57kg = 30kg. So the average weight per child was estimated to be as little as 30kg? What were they, pygmy pre-schoolers?

      1. Anonymous Coward
        Anonymous Coward

        Re: Wouldn't happen in the States ...

        "What were they, pygmy pre-schoolers?"

        Under 12s are not unusual at that weight in England - or at least they weren't about 20 years ago.

      2. Anonymous Coward
        Anonymous Coward

        Re: Wouldn't happen in the States ...

        My 5 year old is 18kg, my 7 year old is 21kg. So I don't think there's anything odd about older schoolkids being 30kg each on average.

    2. Return To Sender

      Re: Wouldn't happen in the States ...

      You get Air Midwest flight 5184 instead.

      http://en.m.wikipedia.org/wiki/Air_Midwest_Flight_5481

      Sadly this one ended up tail heavy. Add in some dodgy outsourced maintenance and you get dead people.

  15. The BigYin

    87kg?

    Feck me. Does that include carry on?

    I'm just shy of 2m, so taller than average, and I'm 85kg, not exactly trim either. Are we really becoming so obese that 87kg is the normal weight?

  16. Anonymous Coward
    Anonymous Coward

    Give it a few years...

    Many airports are now putting in Self-Boarding Gates, where the passenger scans their own barcode, and the airline DCS system says yes or no and opens the gate.

    It's not inconceivable to add an "exit gate" to the back of one of these gates, and make the bit in the middle weigh the passenger and their hand luggage/baby, and not release the exit gate until the weight's been accurately measured. You know what seat the passenger is sitting in (it's encoded in the barcode along with all manner of useful information), and if you know what their weight is, you could feed it into a load planning piece of software, which at the very least would flag up any discrepancies and advise resolutions, and at best would tell the pilots exactly what flight parameters to use for a given aircraft loaded with a given set of fuel, cargo, and passengers.

    Also, you could add an contactless payment card reader to the exit gate to charge heavy people more. Surprised some of the low cost carriers haven't done this yet. People will argue it's discriminatory, but the weight you carry impacts on the fuel you need to carry...

    Disclaimer - I work in the aviation software industry, and I'm heavy.

    1. SkippyBing Silver badge

      Re: Give it a few years...

      Even better, weigh them and then allocate their seat, or at least restrict the ones they can choose from if necessary. That way you save on asking all the lard-os down the back to move to the middle after everyone's got their hand luggage stowed.

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