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2395511047
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Joined: Sun Mar 07, 2021 3:22 pm

A330neo Alternate Nosewheel Steering

Mon Apr 19, 2021 10:05 am

Does anyone know what the ALTN N/W STRNG guarded button does on some A330-900neos? Why would this be a new option, and why would a customer opt for it?

https://imgur.com/Zqlz7Tz

On the A330ceo (I presume the NEOs as well), the Nose Wheel Steering is actuated by the Green Hydraulic System. Is this a way to power NWS off another Hydraulic system?

This seems to be a customer option, and the only A330neos I have seen that have this is the Air Mauritius ones. (TAP, Hifly, Delta, etc. dont have this)
 
787SIN
Posts: 91
Joined: Thu Mar 09, 2017 6:00 am

Re: A330neo Alternate Nosewheel Steering

Thu Apr 22, 2021 12:05 am

Probably a manual reversion to an alternate source of hydraulics for the NWS. The A340-500/600 had similar, with yellow pressure being supplied to the NWS actuators in the event of loss of green system, this though was automatic on the -500/600s. So perhaps they have gone for a simplified arrangement rather than having it controlled by the BSCUs.
 
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Starlionblue
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Joined: Fri Feb 27, 2004 9:54 pm

Re: A330neo Alternate Nosewheel Steering

Thu Apr 22, 2021 12:12 am

The ALTN N/W STRG function is an option on the A330CEO as well. If set to on, the hydraulic yellow system provides nose wheel steering, as opposed to the normal green system. Only for use on the ground.

BTW you can embed images from Imgur.

Image
 
GalaxyFlyer
Posts: 8317
Joined: Fri Jan 01, 2016 4:44 am

Re: A330neo Alternate Nosewheel Steering

Thu Apr 22, 2021 12:14 am

Starlionblue wrote:
The ALTN N/W STRG function is an option on the A330CEO as well. If set to on, the hydraulic yellow system provides nose wheel steering, as opposed to the normal green system. Only for use on the ground.

BTW you can embed images from Imgur.

Image


When would you use ALTN NWS in the air? :P
 
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Starlionblue
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Re: A330neo Alternate Nosewheel Steering

Thu Apr 22, 2021 1:28 am

GalaxyFlyer wrote:
Starlionblue wrote:
The ALTN N/W STRG function is an option on the A330CEO as well. If set to on, the hydraulic yellow system provides nose wheel steering, as opposed to the normal green system. Only for use on the ground.

BTW you can embed images from Imgur.

Image


When would you use ALTN NWS in the air? :P


Haha yes.

I'm just quoting the FCOM, which does have that note. :lol:
 
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zeke
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Re: A330neo Alternate Nosewheel Steering

Thu Apr 22, 2021 9:20 am

GalaxyFlyer wrote:
When would you use ALTN NWS in the air? :P


Obviously during airtaxi operations :)
 
2395511047
Topic Author
Posts: 7
Joined: Sun Mar 07, 2021 3:22 pm

Re: A330neo Alternate Nosewheel Steering

Fri Apr 23, 2021 4:38 pm

Starlionblue wrote:
The ALTN N/W STRG function is an option on the A330CEO as well. If set to on, the hydraulic yellow system provides nose wheel steering, as opposed to the normal green system. Only for use on the ground.

BTW you can embed images from Imgur.

Image


Why would an airline want such function? I assume under MEL you are not allowed to dispatch an A330 with GREEN HYD SYS inop.....

And if it fails on the ground, why not just get towed..... you're not going flying anyway...
 
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fr8mech
Posts: 8311
Joined: Mon Sep 26, 2005 9:00 am

Re: A330neo Alternate Nosewheel Steering

Fri Apr 23, 2021 7:02 pm

2395511047 wrote:

Why would an airline want such function? I assume under MEL you are not allowed to dispatch an A330 with GREEN HYD SYS inop.....

And if it fails on the ground, why not just get towed..... you're not going flying anyway...


Maybe the operator wants to be able to clear the runway in the event of a failure.

Maybe they like all the bells and whistles on their aircraft.
 
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Starlionblue
Posts: 20798
Joined: Fri Feb 27, 2004 9:54 pm

Re: A330neo Alternate Nosewheel Steering

Sat Apr 24, 2021 12:50 am

2395511047 wrote:
Starlionblue wrote:
The ALTN N/W STRG function is an option on the A330CEO as well. If set to on, the hydraulic yellow system provides nose wheel steering, as opposed to the normal green system. Only for use on the ground.

BTW you can embed images from Imgur.

Image


Why would an airline want such function? I assume under MEL you are not allowed to dispatch an A330 with GREEN HYD SYS inop.....

And if it fails on the ground, why not just get towed..... you're not going flying anyway...


Indeed you cannot dispatch with any of the hydraulic systems inop.

As fr8mech, says, it sounds like one of those bells and whistles things. Some airlines just want every option I guess. :D
 
GalaxyFlyer
Posts: 8317
Joined: Fri Jan 01, 2016 4:44 am

Re: A330neo Alternate Nosewheel Steering

Sat Apr 24, 2021 3:06 am

If you go to out of the way places, it might provide a way to clear the runway instead of using a non-existent tug. The C-5 had a alternate NWS source, for what that’s worth. But, we could service a leaking system in-flight, so sometimes, depress the system, fill it, leave it depressed until needed for landing, when configured, rearrange the hydraulic power so you could land with one system depressed, or leave it pressurized until it ran out of fluid. We could also isolate just about anything hydraulic to get around a leak.
 
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Francoflier
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Re: A330neo Alternate Nosewheel Steering

Sat Apr 24, 2021 4:30 am

There is a host failures that can render the nosewheel steering inoperable on the A330. Anything from losing the green hydraulic system to emergency lowering of the gear for whatever reason to brake failures or BSCU issues or even electrical failures.

I guess losing the nosewheel steering wasn't considered a big issue back when the A330/340 was designed as long as you could land and maintain enough directional control to stop on the runway, but nowadays blocking a runway at a major international airport for the amount of time it takes to scramble a tug and pull the aircraft out of the way is big trouble, meaning big money, which the airport might try to recover from the operator one way or the other...

Given that, for an operator with a large enough fleet, this is an occurrence that will happen once or twice a year, having a bypass system that allows to taxi clear of the runway may well be worth the money.

Try pulling that off at LHR or JFK, for instance, and we're talking millions, if not tens of millions in cost of diversions for other airlines and lost revenue for the airport that everyone will try to charge you for... all for a relatively minor failure.

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