salim
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"DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 3:23 am

Why?? I noticed this on mea a330.
 
FDXmech
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 3:45 am

I think you are refering to this NO TOW warning on the nose gear door.


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This red warning area alerts the tug driver the maximum permissable towbar angle during pushout.
You're only as good as your last departure.
 
Mr Spaceman
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 3:45 am

Hello Salim.

I'm curious about your question too.

I'm also wondering ........ was this a permanent decal/marking, or was it a temporary notice?

I'm looking forward to what the possible reasons could be from the mechanics in here.


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Chris  Smile

"Just a minute while I re-invent myself"
 
salim
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 3:50 am

I'm sorry, i wanted to say on the nose wheel door. Thats exactly what FDXmech told us.
thank you!
 
FDXmech
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 3:57 am

Salim

I tried finding a close-up of an MEA A330 nose gear to no avail. MEA's A330 paint scheme is beautiful, I must say.
You're only as good as your last departure.
 
Mr Spaceman
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 4:10 am

Hi guys.

> FDXmech, if you enlarge the photo I posted of a MEA A330, you can see the exact same red warning area on the nosegear door.

Thanks for clearing up that the warning sign says NO TOW instead of DO NOT TOW!


Chris  Smile
"Just a minute while I re-invent myself"
 
codeshare
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 7:26 am

It could mean do not to forward? When the a/c is full of passengers?

There are some angles at which the front gear cannot turn, I believe.
I once saw a situation where the tow bar almost broke when the a/c was being pushed back in the wrong manner.
How much A is there is Airliners Net ? 0 or nothing ?
 
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RayChuang
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 4:50 pm

Here's a question though: what about these newer-generation airplane tugs that literally lift the nose wheel when the plane is being moved around by the tug?  Confused
 
Shenzhen
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 7:18 pm

On most airplanes, you need to disconnect the scissor link that is attached to both the inner cylinder and the outer cylinder (aft side of the gear). When the link is disconnected, the inner cylinder can be turned a lot futher then the markings on the door.

If the newer generation tugs attach to the inner cylinder of the gear, the restrictions would still apply, since it will damage to the nose gear/steering system. Notice the steering actuators on the fwd portion of the gear attach to the inner cylinder via the scissor link.

Cheers.
 
747Teach
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 10:07 pm

Salim: The maximum turning limit when towing the A330 from the nose gear is 65 degrees. The placard on the nose gear door is there to warn the tractor driver he has reached that limit. The limit is 65 degrees whether you use a towbar, or towbarless tractor, or whether you tow from in front of or behind the nose gear. You do not need to disconnect the scissor link to tow. You do need to pressurize the blue hydraulic system, de-energize the steering system, and follow all other maintenance and safety procedures. This is from the A330 AMM, Chapter 09-00-00 and 09-10-00. Regards,
 
Shenzhen
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Wed Jan 07, 2004 10:54 pm

747Teach

Maybe I wasn't clear enough. If you disconnect the scissor link, you can turn the nose gear beyond the markings on the gear door (on most every airplane I've seen). If you don't, and the shear bolt in the tow bar doesn't shear, then you have damaged the links and or possibly the steering collar and such.

Cheers
 
FDXmech
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Thu Jan 08, 2004 1:24 am

Right. Generally speaking, these markings apply when the scissors remain connected and the steering bypass valve is positioned to "bypass" or hydraulic pumps remain off.

These steering limits are usually more than sufficient with the tug/towbar/aircraft potentially nearing a "jackknifed" condition as the max angle is reached. Very undesireable with engines running.

Some aircraft, the removal of the apex pin (to split the scissors) is impractical as it is bolted and cotterpinned.

On some aircraft the scissors, though easily split are difficult to rejoin due to tight tolerances and difficulty in moving the links.

You're only as good as your last departure.
 
747Teach
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Thu Jan 08, 2004 2:56 am

Shenzhen: The A330 AMM outlines towing in the following tasks: 09-10-00-584-802, REF 203/TAsk 09-10-00-991-002 Sheet 1, and REF 204/Task 09-10-00-991-011 Sheet 1. Step 1 says the maximum turning angle is 65 degrees either side of the aircraft centerline. There is no reference given for disconnecting the scissor link. The "NO TOW" placard means "NO TOW," for whatever reason, scissors disconnected or not. I understand what you're saying about disconnecting the scissor link. I disagree that you would do this "on most airplanes." But the original question was about the A330, not generally or "about every plane I've seen." You may be interested in knowing that at 93 degrees, the Nose Landing Gear Steering Angle Protection System, AMM Chapter 32-53-00, will come into play, and activate two fault lights warning the tow crew and the flight deck that the maximum turning angle has been exceeded. Regards,
 
Shenzhen
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Thu Jan 08, 2004 1:31 pm

747Teach

I'm certainly not going to argue with a guy over specifics, when I replied off the top of my head, and you looked it up in the books.

You may be interested to know that, if the scissor links are disconnected, you can't steer the airplane. thus you probably wouldn't get any warning what so ever.

Look it up and let me know.

Cheers
 
cdfmxtech
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Thu Jan 08, 2004 4:02 pm

You may be interested to know that, if the scissor links are disconnected, you can't steer the airplane. thus you probably wouldn't get any warning what so ever.

The Nose Landing Gear (NLG) Steering Angle Protection System gives a visual warning of excess angular travel of the NLG steering during towing operations.
The warning is not for normal steering operations, although it would be pretty hard to get to 93 degrees anyway when the tillers are limited to 78, and to get to that takes an override.

(P.S. - I've never worked Airbus, but I did stay at a Holiday-Inn Express last night Big grin)
 
747Teach
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Thu Jan 08, 2004 10:25 pm

Shenzhen: I am aware that if the scissors are disconnected, you can't steer the airplane. However, you will get a warning. The BSCU will see an angular difference between the LVDT on the servo valve, the RVDT on the gearbox on the turning tube, and the handwheel. This will cause BSCU to generate the N/W STRG FAULT on the E/WD, and the SD will show N.W. STRG in amber on the WHEEL page. A330 AMM 32-51-00 PB001. And for CdfMxTech: The A330 steering system handwheels have 75 degrees of travel either way, giving you 72 degrees of steering motion, which is always available below 10 knots. Same reference. Regards,
 
cdfmxtech
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Fri Jan 09, 2004 2:04 am

747Teach

I guess I'll have to take your word for it. I don't know how current that material is. Says that 65 degrees is available normally, but 78 can be achieved by overriding a sort of detent or frangible fitting.
This is all dependent upon speed, meaning less is available the faster the aircraft is moving.
 
747Teach
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Fri Jan 09, 2004 4:41 am

CdfMxTech: Effectivity ALL, Revision October 28, 2003. Regards,
 
buckfifty
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Fri Jan 09, 2004 8:10 pm

The nosewheel steering on the Airbus is software limited, I believe, at the BSCU. The steering used to be limited to 65 degrees left or right of centre because of some fault with the torque link (I think) on the 330 and 340, but has since been upgraded to 72.
 
Joule
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RE: "DO NOT Tow" On A330 Nose Wheel Gear.

Tue Jan 20, 2004 12:02 am

Yes the nosewheel steering is software limited from the BSCU. Some aircraft still have 65 deg and others 72 deg, depending on BSCU standard and also depending on the landing gear standard (if I'm not mistaken). Originally all A330/A340s had 78 deg but after the Sabena A340 had its MLG fractured on landing some years back (due to fatigue or stress of some sort on the MLG), Airbus changed the steering limits so as not to stress the LGs.

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