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limitation on taxi speed

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limitation on taxi speed

Old 6th Aug 2018, 15:59
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limitation on taxi speed

Hi guys

regarding the limitation on taxi speed, the manual says ... when taxi weight is higher than 76 000 kg do not exceed a taxi speed of 20kt during a turn, the limitation is only applicable for the A320CEO and not for the NEO, I wonder why, why is there a limitation on taxi speed at all, it there a tyre issue, nose wheel skidding?
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Old 6th Aug 2018, 18:48
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Nosewheel skid.
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Old 6th Aug 2018, 19:18
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Turning an aircraft at speed is not particularly clever at the best of times..... you get significant wear and tear to nose wheels as well as some seriously pissed of crew down the back......
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Old 6th Aug 2018, 19:25
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Originally Posted by frankice View Post
Hi guys

regarding the limitation on taxi speed, the manual says ... when taxi weight is higher than 76 000 kg do not exceed a taxi speed of 20kt during a turn, the limitation is only applicable for the A320CEO and not for the NEO, I wonder why, why is there a limitation on taxi speed at all, it there a tyre issue, nose wheel skidding?
May also be MLG strut or mainwheel side loading.

My type has specific fuel limits also as the rush of fuel to one end of the wing tank can seriously damage the internal fuel baffles if you give it some welly in the turn above 20 Kt.
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Old 6th Aug 2018, 21:54
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Thank you VinRouge! That make sense
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Old 6th Aug 2018, 22:00
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One really had to come here to ask a question such as this? Is this where aviation has gone?
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Old 6th Aug 2018, 23:19
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Originally Posted by LimaFoxTango View Post
One really had to come here to ask a question such as this? Is this where aviation has gone?
In a bid to satisfy the customer? The customer is (nearly) always right, come the bottom line. In these days of social media the views of the end-line customer prove to be very effective. Do your customers want to be thrown about? (Depends on customs, I suppose.) AFAIK many airlines have SOPs which generally prevent their customers from being unnecessarily thrown about in the cabin. Seems reasonable, given the flack?

It mightnít be helpful to efficiency targets but itís something to deal with, and understand. From an ATC point-of-view I will (almost always) ask crew if they are able ďexpeditious backtrackĒ etc if the gap is tight. If not, Iíll alter my plan. Itís not rocket science, nor is it ununderstandable...

In ATC terms we need to know if you can accept a rocket-propelled backtrack, or not. It affects what we do. It affects how (certainly) ďmyĒ airport operates.

So yes, this is where aviation has gone, and where it will be centred on....customer experience, positive (hopefully) reviews and recommendations. Not rocket science...
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Old 7th Aug 2018, 04:40
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Originally Posted by good egg View Post


In a bid to satisfy the customer? The customer is (nearly) always right, come the bottom line. In these days of social media the views of the end-line customer prove to be very effective. Do your customers want to be thrown about? (Depends on customs, I suppose.) AFAIK many airlines have SOPs which generally prevent their customers from being unnecessarily thrown about in the cabin. Seems reasonable, given the flack?

It mightnít be helpful to efficiency targets but itís something to deal with, and understand. From an ATC point-of-view I will (almost always) ask crew if they are able ďexpeditious backtrackĒ etc if the gap is tight. If not, Iíll alter my plan. Itís not rocket science, nor is it ununderstandable...

In ATC terms we need to know if you can accept a rocket-propelled backtrack, or not. It affects what we do. It affects how (certainly) ďmyĒ airport operates.

So yes, this is where aviation has gone, and where it will be centred on....customer experience, positive (hopefully) reviews and recommendations. Not rocket science...
You started your post by highlighting the reason why an aircraft taxis is nice and slow; passenger comfort. Then as a controller you ask a pilot to expedite his taxi so your airport can run efficiently, disregarding passenger comfort. Whatís your point really? Anyway, I didnít think someone had to ask why one canít taxi around a corner at 20+ kts.
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Old 7th Aug 2018, 05:30
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Originally Posted by LimaFoxTango View Post


You started your post by highlighting the reason why an aircraft taxis is nice and slow; passenger comfort. Then as a controller you ask a pilot to expedite his taxi so your airport can run efficiently, disregarding passenger comfort. Whatís your point really? Anyway, I didnít think someone had to ask why one canít taxi around a corner at 20+ kts.
To be fair, LFT, the OP was asking why there is a difference in the limitations between A320 CEO and A320 NEO.

Also, as I am not involved in type certification/testing, I don't know what the limitation is the designers had in mind when they designed that 76t,/20kt limit, nor why this reason magically disappeared on the NEO. If this is so obvious, maybe you could enlighten us?
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Old 7th Aug 2018, 06:01
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A little inside brake brake going around the corner does wonders to avoid nose wheel
skidding
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Old 9th Aug 2018, 09:15
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Originally Posted by LimaFoxTango View Post
One really had to come here to ask a question such as this? Is this where aviation has gone?
I'd be worried if aviation had gone to a place where people got looked down upon for asking about a question they don't know the answer to...
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Old 9th Aug 2018, 20:15
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Originally Posted by LimaFoxTango View Post


You started your post by highlighting the reason why an aircraft taxis is nice and slow; passenger comfort. Then as a controller you ask a pilot to expedite his taxi so your airport can run efficiently, disregarding passenger comfort. Whatís your point really? Anyway, I didnít think someone had to ask why one canít taxi around a corner at 20+ kts.
Did I say anything about cornering at speed? Iím pretty sure I said ďbacktrackĒ...most runways I know are pretty straight....

Before this drifts too much, itís good for ATC to know operator limitations. Itís also good to know these limitations when modelling airport capacity.

Iím guessing the 20kt limitation above doesnít include initial turn onto RET (shallow turn radius) after landing but is a limit for standard turn radius on taxiways and taxiway intersections?

Last edited by good egg; 10th Aug 2018 at 04:47. Reason: More explanation
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Old 9th Aug 2018, 21:53
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why is there a limitation on taxi speed at all, it there a tyre issue, nose wheel skidding?
I doubt it is a tyre skidding problem. Tyre friction increases with the weight on the tyre, so weight doesn't affect the stopping / cornering limit.
It is more likely to be a sideways nose gear loading limit. Maybe the NEO has a stronger nose gear.
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Old 10th Aug 2018, 09:50
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Originally Posted by good egg View Post


Iím guessing the 20kt limitation above doesnít include initial turn onto RET (shallow turn radius) after landing but is a limit for standard turn radius on taxiways and taxiway intersections?
What makes you say that? That's as logical as the pilot that turns the brake fans off 5sec before departure and says, "fans are off so the temp limit is now 300 degrees". A limitation is a limitation. There is no note or exception for RET.

In any event, considering the max Landing weight of an A320 CEO is 66t, so clearly it is not an issue.
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Old 10th Aug 2018, 10:41
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Originally Posted by The Shovel View Post
What makes you say that? That's as logical as the pilot that turns the brake fans off 5sec before departure and says, "fans are off so the temp limit is now 300 degrees". A limitation is a limitation. There is no note or exception for RET.

In any event, considering the max Landing weight of an A320 CEO is 66t, so clearly it is not an issue.
Observation makes me say that....but I see thatís to do with the weight restriction. Thanks
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Old 14th Aug 2018, 23:56
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Originally Posted by frankice View Post
Hi guys

regarding the limitation on taxi speed, the manual says ... when taxi weight is higher than 76 000 kg do not exceed a taxi speed of 20kt during a turn, the limitation is only applicable for the A320CEO and not for the NEO, I wonder why, why is there a limitation on taxi speed at all, it there a tyre issue, nose wheel skidding?
Its is funny the forth right opinion on here, wrong as most of it is. Its got nothing to do with the nose gear. The issue affects all 'heavy' jets, the higher the weight the higher the tyre stress and resultant temperatures. Ideally, in high ambient temps, high gross weight, particularly on less than 1 hour turns; you should taxi at 15kts maximum and 10kts for turns. Save your tyres as you never know when they might let you down
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Old 15th Aug 2018, 00:28
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Originally Posted by Dogma View Post
Its is funny the forth right opinion on here, wrong as most of it is. Its got nothing to do with the nose gear. The issue affects all 'heavy' jets, the higher the weight the higher the tyre stress and resultant temperatures. Ideally, in high ambient temps, high gross weight, particularly on less than 1 hour turns; you should taxi at 15kts maximum and 10kts for turns. Save your tyres as you never know when they might let you down
Is an A320 a Ďheavyí jet then?...
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Old 15th Aug 2018, 05:45
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Originally Posted by Dogma View Post
Its is funny the forth right opinion on here, wrong as most of it is. Its got nothing to do with the nose gear. The issue affects all 'heavy' jets, the higher the weight the higher the tyre stress and resultant temperatures. Ideally, in high ambient temps, high gross weight, particularly on less than 1 hour turns; you should taxi at 15kts maximum and 10kts for turns. Save your tyres as you never know when they might let you down
Not sure about the heavy jets, but 15 kt is really slow on straight line for the A320 family. You would have to brake too many times especially on A319 with IAE engines. For the A320 family, Airbus recommends to let it accelerate up to 30kts on straight line then to brake down smoothly down to 10kt.
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Old 15th Aug 2018, 08:20
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Originally Posted by Dogma View Post
Its is funny the forth right opinion on here, wrong as most of it is. Its got nothing to do with the nose gear. The issue affects all 'heavy' jets, the higher the weight the higher the tyre stress and resultant temperatures. Ideally, in high ambient temps, high gross weight, particularly on less than 1 hour turns; you should taxi at 15kts maximum and 10kts for turns. Save your tyres as you never know when they might let you down
looks like a forthright opinion to me right there.

Once again, the logic leaves a bit to be desired.
Firstly, to taxi at such speeds would require multiple brake applications or you to ride the brakes to limit the speed to 15kts. Now we ALL know that brake wear in modern jets is based on number of applications and not whether the application is heavy or light braking. All of which would cause a large increase in brake temperature, more of an issue on a short turn around, and have little effect on tyre wear.
Do you realise that even at Max LDG Weight, and A320 will accelerate from 0-30kts without the application of any power above idle?
Secondly and probably more important and techincally correct is the Manufacturer's recommendation to allow the aircraft to accelerate to 30kts in a straight line..... as already stated above.

That being said, you are perfectly correct if your aim during taxi is to milk loggable flight hour, piss off any other operator taxiing behind you being forced to ride his brakes.
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Old 15th Aug 2018, 08:25
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Originally Posted by Dogma
Its is funny the forth right opinion on here, wrong as most of it is. Its got nothing to do with the nose gear. The issue affects all 'heavy' jets, the higher the weight the higher the tyre stress and resultant temperatures.
See OP #1. If the restriction does not apply to a heavy NEO, why do you think it is a tyre problem?
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