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. 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...

            1. 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



            2. 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.

            3. 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.

  1. 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 Bronze badge

      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

          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


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


        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.

      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 Brize Norton 18 December 1997

        interview without coffee for culprit(s)?

    6. Naughtyhorse

      Re: YA-clearly-NAP


      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!

  2. Anonymous Coward

    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.

  3. 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.

  4. This post has been deleted by its author

  5. 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...

  6. 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...


  7. 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.

  8. 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....

  9. JaitcH

    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.

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

  10. The BigYin


    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?

  11. 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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