A320 nose wheel tiller

[Higgs boson]

During taxying, if you observe that one of the tiller is unserviceable, would you continue or not? The MEL is silent on the tiller part. It only makes a note of the Nose wheel steering. I am assuming that since it's not mentioned in the MEL it has to be a "NO GO". Any thoughts?

[Jonty]

If you are taxiing the MEL is not relevant. It would be a discussion with maintenance and a command decision, taking into account the MEL, but not ruled by it. As far as actual controllability, you still have rudder pedal steering and differential braking, in addition to the serviceable tiller.

[Higgs boson]

If you are taxiing the MEL is not relevant. It would be a discussion with maintenance and a command decision, taking into account the MEL, but not ruled by it. As far as actual controllability, you still have rudder pedal steering and differential braking, in addition to the serviceable tiller.
Thanks for the reply Jonty. Just curious. How come MEL doesn't mention a word about the tiller!

[iggy]

Maybe because it is included in Nose Wheel Steering Control System?

Meaning, if the tiller is inoperative, the whole system is also inoperative...

[Higgs boson]

Maybe because it is included in Nose Wheel Steering Control System?

Meaning, if the tiller is inoperative, the whole system is also inoperative...

https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1170x1309/0a5bfa0c_c06d_476e_be98_e3984969cc60_3c18992977eb63c1c400eab c3be4fa8bfc31fd2b.jpeg
The MEL only mentions about the NWS control system. The number installed is 1 as you can see. Meanwhile, there are 2 tillers available.

[iggy]

Oooooookay.

One system with two tillers, if two tillers are inoperative, then the one system also is inoperative...?

Just throwing Hail Marys here...

[Jonty]

Looks like if the tiller is U/S the aircraft is AOG. I would imagine this is because the failure mode of the tiller cannot be determined and therefore it must be fixed before dispatch.
If an item cannot be deferred in accordance with the MEL, either because it says not, or because it’s not mentioned, then the aircraft is AOG. The only get out is if it’s clearly a non airworthiness item.

[Check Airman]

I’d be going back to the gate. There must be some way to deactivate the affected tiller. I wouldn’t want it to send an erroneous signal while I’m on the runway.

I’ll have to see what our MEL says about it.

[tubby linton]

I was always taught that if a component is not in the MEL then you are AOG if it is broken. The company maintenance will have access to the MMEL which will be more comprehensive but why would what is effectively an electric switch fail on one side? Liquid in that area ? Where else has it gone? Into the sidestick? Back to the gate and look at the empty coffee cup you put in that area when you know that it shouldn’t have been there.

[WhatShortage]

Not in the Mel = NO GO, what's the point of this thread?
Not in the mel and already on taxi, check mel/ fcom/call operations-techs = no go 99%

[FlightDetent]

Not in the Mel = NO GO, what's the point of this thread?
Not in the mel and already on taxi, check mel/ fcom/call operations-techs = no go 99%Point of the thread is to find out what guidance is mandatory and if any additional printed advice is available for the situation described. The binding pre-dispatch conditions of (M)MEL no longer apply to most operators at this stage.

As you remember for long years until recently, on the SA bus NWS INOP dispatch was permissible. The OP is asking about 1 tiller u/s ...

Additional thoughts
+ CAT III single with manual roll-out is permissible with NWS u/s
+ the post-maintenance check flight schedule prescribes separate verification of tillers Left and Right actually on 2 separate occasions (Airbus reference IS-ATFM E8 & F4).

[CMpilot1]

Don’t forget that you may not be able to make a 180 degree turn without a tiller. Let’s suppose that the Captain side tiller became inoperative during taxiing, and the pilot sitting on the right side is still wet behind the ears. Handing over the controls to the this pilot to make a 180 degree isn’t exactly what I would be looking forward to.

[hans brinker]

Don’t forget that you may not be able to make a 180 degree turn without a tiller. Let’s suppose that the Captain side tiller became inoperative during taxiing, and the pilot sitting on the right side is still wet behind the ears. Handing over the controls to the this pilot to make a 180 degree isn’t exactly what I would be looking forward to.

And that is the reason every aircraft should have 2 tillers, and the FO should taxi on their leg.

[FlightDetent]

Would you trust a captain to make a 180 he's never done before? WTF.

​​Nope. Because he has been through the excerise during the TR course and base training. Same as the F/Os.

Better focus on the fact that A319 cannot go over the edge line, buddy.

​

[Tom Sawyer]

From an Engineering point of view, the answer is as the MEL quoted above. It comes down to it being one system, which includes both tillers. If any part of the control system is not functioning correctly, the whole system is classed as inop, so a no-go. If it was allowable to have one tiller inop, it would be in the MEL as a separate item.

[Higgs boson]

From an Engineering point of view, the answer is as the MEL quoted above. It comes down to it being one system, which includes both tillers. If any part of the control system is not functioning correctly, the whole system is classed as inop, so a no-go. If it was allowable to have one tiller inop, it would be in the MEL as a separate item.
Ok. That sounds logical. Both Tillers could be considered as part of one system-which is NWS system. So, if one tiller is inoperative, it effects the NWS system as well. Since NWS system is a required system, it becomes a NO-GO.

[hikoushi]

May not be helpful to you, but for perspective on use of the MEL after pushback, in US / FAA regulations there is a process we are bound to between pushback and takeoff called “crew placarding”. Essentially the MEL still applies during taxi, until airborne. If an issue arises during taxi-out, once completing the ECAM or other procedure we have to reference the MEL (generally while on the phone with maintenance) and see if an item is crew placard-able. If yes and everyone agrees, we complete the required operational items from the MEL (has to be very simple, like pulling a breaker), get the required paperwork from our maintenance and dispatch offices (over ACARS), and then press on. The tech log is filled out enroute in accordance with the instructions and authorization on that ACARS printout.

If an item is not placardable (which is true in this case since it is not on the MEL at all!), back to the gate we go.

[FlightDetent]

And for that you carry the placards on board, I suppose correctly?