Air2K A320 Tailstrike incident in Greece???
Okay, let's get the physics right.
Applying thrust or applying elevator will not change the aircraft's C of G - the position of the C of G will not change. Problems will result, obviously, if the C of G is outside of specified limits.
Applying take-off thrust will produce an IMMEDIATE pitching-up force (because the engine thrustline is below the aircraft's C of G) which, if the aircraft is loaded properly, will not be sufficient to produce an actual pitch-up. However, applying forward stick WILL NOT apply a pitch-down force until there is sufficient airflow over the elevators to generate the required force.
Therefore in a badly loaded aircraft the aircraft will tend to pitch-up immediately take-off power is applied and forward elevator will not stop this until sufficient speed has built up - and the speed required will be higher the more the aircraft is out of balance - hence the report of the aircraft pitching up at the start of the take-off roll but the nose lowering again further into the roll (ie forward elevator finally became effective).
"To counter the nose-up effect of setting engine take-off thrust, apply half forward stick until the airspeed reaches 80 knots" is not actually correct - the elevators are not effective at the time you are setting take-off thrust!
One final thought, if you actually had a tailwind component at the moment of applying take-off thrust forward elevator could produce a very small DOWNWARD force on the tail and exacerbate the problem!
Applying thrust or applying elevator will not change the aircraft's C of G - the position of the C of G will not change. Problems will result, obviously, if the C of G is outside of specified limits.
Applying take-off thrust will produce an IMMEDIATE pitching-up force (because the engine thrustline is below the aircraft's C of G) which, if the aircraft is loaded properly, will not be sufficient to produce an actual pitch-up. However, applying forward stick WILL NOT apply a pitch-down force until there is sufficient airflow over the elevators to generate the required force.
Therefore in a badly loaded aircraft the aircraft will tend to pitch-up immediately take-off power is applied and forward elevator will not stop this until sufficient speed has built up - and the speed required will be higher the more the aircraft is out of balance - hence the report of the aircraft pitching up at the start of the take-off roll but the nose lowering again further into the roll (ie forward elevator finally became effective).
"To counter the nose-up effect of setting engine take-off thrust, apply half forward stick until the airspeed reaches 80 knots" is not actually correct - the elevators are not effective at the time you are setting take-off thrust!
One final thought, if you actually had a tailwind component at the moment of applying take-off thrust forward elevator could produce a very small DOWNWARD force on the tail and exacerbate the problem!
Last edited by Groundloop; 13th Dec 2002 at 11:46.
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Mr 777- <As for the person who said "loadsheet procedures would ensure that this NEVER happens",what utter nonsense!!!I know plenty of people who have made errors in loading,inputting data onto loadsheets etc. that could,in serious circumstances,have resulted in this outcome.>
Well that was me, and it was correct. Proper loadsheet procedures would ensure this never happens. When human idiots interfere and mess things up with incorrect data, it may happen, but if those loading staff adhered to procedures, it would not. So pray, where is the 'utter nonsense'?
Well that was me, and it was correct. Proper loadsheet procedures would ensure this never happens. When human idiots interfere and mess things up with incorrect data, it may happen, but if those loading staff adhered to procedures, it would not. So pray, where is the 'utter nonsense'?
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Cabin Crew are trained about pax distribution for trim - but not to the level of detail that applies to flight crew. Any cabin crew member worth his/her salt should advise flight crew when the load is clearly, heavily unbalanced: This is part of our job, and should be in the ops or SEP manuals.
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Horatio - I agree with you completely, and an aft CofG can only exacerbate the problem.
Groundloop - I agree with your physics lesson, however you say that the statement "To counter the nose-up effect of setting engine take-off thrust, apply half forward stick until the airspeed reaches 80 knots"is not actually correct. Well, like I said this satement comes directly from Airbus Industrie !
GF
Groundloop - I agree with your physics lesson, however you say that the statement "To counter the nose-up effect of setting engine take-off thrust, apply half forward stick until the airspeed reaches 80 knots"is not actually correct. Well, like I said this satement comes directly from Airbus Industrie !
GF
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I'd be quite surprised to hear Airbus say something like: "disregard, just pretend the problem isn't there, the computer will solve it for you later, and continue the takeoff roll. To keep yourself busy, just push the stick forward. It doesn't change anything when the problem initially appears and you're vulnerable, but you should feel better and at least you'll be able to say the CAA investigators that you did something about it. Oh, and don't even think about aborting and going back to the ramp to fix this, it looks bad in the stats."
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As a Load Controller & dispatcher ALL A320 aircraft should be loaded fwd hold first and unloaded aft hold first to avoid posibility of tipping.
Pax distribution is also a factor and if boarding from an airbridge the middle section of the a/c are boarded first.
just my 2 cents worth.
Pax distribution is also a factor and if boarding from an airbridge the middle section of the a/c are boarded first.
just my 2 cents worth.
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If the Dry Operating Index is incorrect, or input into a computer incorrectly, then your starting point is wrong. It is then relatively easy for this situation to occur. If you fly an aircraft that has fuel in the tail, even more so.
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It happend twice to me in Greece (same airport) that the loading
was incorrect. Ground staff told us how they loaded the airplane and how much baggage etc. and it turned out to be totally wrong.
Was quite a moment during t/o. Aircraft pitched up violently
during rotation. Fortunately no tailstrike.
So eventhough you sign for a loadsheet it is only as good as the
info that they gave you to make it. But you can hardly check all
the bags for yourself.
was incorrect. Ground staff told us how they loaded the airplane and how much baggage etc. and it turned out to be totally wrong.
Was quite a moment during t/o. Aircraft pitched up violently
during rotation. Fortunately no tailstrike.
So eventhough you sign for a loadsheet it is only as good as the
info that they gave you to make it. But you can hardly check all
the bags for yourself.
None but a blockhead
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This might be a silly question, but can't the a/'c tell if there's a dangerous CoG while it's sitting at the gate by measuring the differential loading on the gear? Why wait for aerodynamics to tell you?
R
R
