Mr.BA
Topic Author
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

Nose Gear Off-centre

Wed Jun 02, 2004 12:32 pm

Hi guys,

It's been sometime sicne I posted here.  Smile


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Just wondering, what causes the nose gear to be off-centered? Steering tiller not put backed to neutral?

The caption reads that the pilot used the remaining runway left for take-off after inspection on the nose gear and found no problems. It seems to me that it's no proper procedure to do this as it would affect your V1, Vr, rejected take-off length... etc? Or did the pilot just went full power and off he went?

Thanks cheers

alvin  Big grin
Boeing747 万岁!
 
liamksa
Posts: 301
Joined: Mon Oct 29, 2001 1:13 pm

RE: Nose Gear Off-centre

Wed Jun 02, 2004 1:29 pm

I don't know anything re: the procedures but typical takeoff configuration warnings include slats and flaps, spoilers, stabiliser and park brake. If any of these are not where they should be the crew will soon know about it. Looks like for the 747 (and most aircraft?) there is no takeoff config warning re: tiller position (if that even was the problem - may have had nothing to do with it).

As for the takeofff with the remaining runway available I somehow doubt it but wasn't there to witness it (obviously). The company i'm with doesn't even allow intersection departures with light aircraft and you're always required to use the full length. I would have though EK had a similar requirement?
 
meister808
Posts: 924
Joined: Sat Jan 01, 2000 11:45 am

RE: Nose Gear Off-centre

Wed Jun 02, 2004 1:34 pm

He did a takeoff, after inspection and reset. The t/o wouldn't have happened if the problem couldn't have been fixed right then and there. If the problem was fixed, then the V-speeds and such wouldn't have to be recalculated, since the only thing that changed from the original calculations is the a/c is a bit lighter b/c of fuel burned on the RTO for the offset nosegear. That should be pretty negligible, and even if it isn't, using the calculated numbers will only give a better margin of error.

I hope that was moderately clear.

And I don't know what causes a takeoff to be made with the nosewheel off center.

-Meister
Twin Cessna 812 Victor, Minneapolis Center, we observe your operation in the immediate vicinity of extreme precipitation
 
Bellerophon
Posts: 516
Joined: Thu May 09, 2002 10:12 am

RE: Nose Gear Off-centre

Wed Jun 02, 2004 7:29 pm

Mr.BA

Looking closely at this photo, the #4 engine does not appear to be rotating, as the spinner seems to be stationary.

Full left rudder and full left nose-wheel steering are also being applied, which leads me to speculate that this may have been a three-engined take-off that had to be abandoned at low speed, possibly because of an inability to keep the aircraft straight during the early part of the take-off roll.

If this was the case, two possible causes for any such a loss of directional control could be, firstly, an unexpected adverse cross-wind (in this case from the right) or, secondly, applying too much power from #1 engine, too quickly, at too low an airspeed.

In the major airlines, because of the complexity of such take-offs, there are generally only a few pilots, who have undergone special simulator training, who are authorised to conduct three-engined take-offs.

Such take-offs are generally done in order to move the aircraft to a more suitable maintenance facility, where engine repairs or an engine change can be carried out, and are only performed on an empty aircraft with no passengers.

As I said, however, this is just my speculation

Regards

Bellerophon



 
buckfifty
Posts: 1278
Joined: Tue Oct 16, 2001 4:05 pm

RE: Nose Gear Off-centre

Wed Jun 02, 2004 8:27 pm

Good catch, Bellerophon. It's definitely not a tiller problem, looking at the amount of left rudder that is being applied. The pilot probably also used the tiller in addition to the rudder pedals to keep the aircraft on the runway as it was slowing down, as I don't think the rudder alone can give such a severe steering tilt angle.

It could have been a three engined ferry gone wrong as you have described, or the #4 engine failed, with a slow reaction from the crew to shut it all down. Or it probably has been shut down, but the other three engines are still windmilling. Though the latter seemingly is unlikely, as the spoilers are seemingly still down.

Interesting photo nevertheless.
 
411A
Posts: 1788
Joined: Mon Nov 12, 2001 10:34 am

RE: Nose Gear Off-centre

Thu Jun 03, 2004 1:56 am

More than likely a slight in-attention problem...ie: body gear steering not dis-armed for takeoff, or a body gear steering malfunction.
Have watched a few 747's like this before, while awaiting takeoff in the TriStar I was operating.
One, a PAL 747 at CDG, ended up in the weeds. They were very light, which didn't help the situation either.
 
Mr.BA
Topic Author
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: Nose Gear Off-centre

Thu Jun 03, 2004 8:31 am

Right thanks guys.. made a lot of sense. Didn't notice engine 4 was really turning... but looks quite spetacular Smile

Cheers  Big grin
Boeing747 万岁!
 
Jetfixer75
Posts: 29
Joined: Sun May 16, 2004 2:21 pm

RE: Nose Gear Off-centre

Sun Jun 13, 2004 3:52 pm

Not too sure about how much steering input the 744 has with the rudder pedals, but the 737 has 7.5 degrees withe the pedals. As far as the recentering of the nose gear, when the gear comes up off the ground, there are centering cams inside the NLG strut to straighten the wheels out prior to going up in the nose wheel well. Unfortunately, if the NLG strut is overserviced with nitrogen, the keys that hold the cams in place can be sheared off, thus not allowing the inner strut to recenter.
 
Silver1SWA
Crew
Posts: 4458
Joined: Wed Mar 10, 2004 6:11 pm

RE: Nose Gear Off-centre

Sun Jun 13, 2004 5:36 pm

This same photo was already deiscussed with heavy debate.

[Edited 2004-06-13 10:37:18]
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
airplay
Posts: 3369
Joined: Sat Oct 25, 2003 1:58 am

RE: Nose Gear Off-centre

Mon Jun 14, 2004 12:02 am

Nose gear is typically forced to center after takeoff. The oleo is self centering as the gear leg extends. However, if you rotate and the nose wheel is deflected at the right time, the air load works against the nose oleo centering mechanism.

It is a bad thing to use nose wheel steering at advanced airspeeds as the air load can snag the wheel quite easily.
 
FDXmech
Posts: 3219
Joined: Sun Mar 19, 2000 9:48 pm

RE: Nose Gear Off-centre

Mon Jun 14, 2004 2:14 pm

That's some picture. It would seem if the nose wheels cocked like that during T/O, it would have departed the runway.

With all that smoke coming from the nose tires, I would have guessed it was landing, though I suppose they would have flat spotted..

Also, it looks to me like only 4 has the spinner paint and the others don't.

[Edited 2004-06-14 07:19:18]
You're only as good as your last departure.
 
videns
Posts: 132
Joined: Thu Mar 18, 2004 3:28 pm

RE: Nose Gear Off-centre

Mon Jun 14, 2004 3:42 pm

If the #4 engine is not working, shouldn't the pilot be steering to the right, and not the left, like this picture shows?? It looks to me like it was "just" a malfunction in the steering systems of the aircraft, otherwise, you would apply rudder opposite to the non-working engine. Right engine dead, apply left rudder; left engine dead, apply right rudder.....
Travel? Why would i travel if I can watch it on TV?
 
dl757md
Posts: 1482
Joined: Mon May 24, 2004 9:32 am

RE: Nose Gear Off-centre

Mon Jun 14, 2004 4:07 pm

If the #4 engine is not working, shouldn't the pilot be steering to the right, and not the left, like this picture shows??

If you have both engines on the left side of the plane working and only the inboard engine on the right side of the plane working then the resulting differential thrust would try to turn the airplane to the right. To conteract this you would steer to the left.

otherwise, you would apply rudder opposite to the non-working engine. Right engine dead, apply left rudder; left engine dead, apply right rudder.....

Actually you just answered your own question "right engine dead, left rudder", and if your not going fast enough yet for rudder authority you would steer the nose wheel to the left.

DL757md
757 Most beautiful airliner in the sky!
 
videns
Posts: 132
Joined: Thu Mar 18, 2004 3:28 pm

RE: Nose Gear Off-centre

Mon Jun 14, 2004 4:20 pm

DL757md;
That's what I'm talking about. On the picture, you see the rudder and steering trying to take the aircraft to the left, when they should have been correcting heading in the opposite direction, and that's why I say it was some other kind of malfunction.
Travel? Why would i travel if I can watch it on TV?
 
dl757md
Posts: 1482
Joined: Mon May 24, 2004 9:32 am

RE: Nose Gear Off-centre

Mon Jun 14, 2004 4:27 pm

Videns
Yes the rudder and nose steering are trying to take the AC left.
The #4 engine out(furthest right engine)condition is trying to take the AC right. Less thrust on a side of an AC turns the AC in the same direction. Left engine out=left turn, right rudder or steering counteracts this to keep the plane straight. Right engine out(#4)=right turn, left rudder or steering counteracts this to keep the plane straight.

[Edited 2004-06-14 09:45:23]
757 Most beautiful airliner in the sky!
 
tangoecho
Posts: 123
Joined: Thu May 13, 2004 3:10 am

RE: Nose Gear Off-centre

Tue Jun 15, 2004 5:49 am

Same thing happened to a jetstream 31 at ABZ last month.
It turned out to be hydraulic failure. As soon as the nose wheel touched down it righted itself.


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