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lynn789
4th Apr 2010, 22:20
recently a Qantas A380 landed with 2 wheels locked by the brakes both on 1 side, quite a lightshow from scraping wheels as it was after dark.

any comments?

could the plane have been kept on the runway if all wheels had been locked up on one side....

I fly the pacific with them soon as a pax and their continuing mishaps are a concern, I usually avoid them but a very cheap seat with a powerpoint for my breathing machine, and permission to use it, was an offer I couldnt refuse

muduckace
4th Apr 2010, 22:54
Not knowing the technics of the aircraft, sounds like a common valve that did not release hyd pressure. I am sure the aircraft has brake temp monitoring so I doubt 2 brakes had mechanically seized. Most aircraft shoot a burst of pressure on retraction to stop wheel movement before the gear is in the well, While it may be possible it is unlikely the aircraft departed in this condition.

Chris Scott
4th Apr 2010, 23:00
Hi,

The minor incident you refer to has been covered by PPRuNe on another thread here (http://www.pprune.org/spectators-balcony-spotters-corner/410693-qf32-a380-blows-tyres-landing.html).
For some reason your query has come up on this technical section, used mainly by aircrew and engineers.

As a retired airline pilot (not with them), let me reassure you that Qantas is one of the safest and most highly respected airlines of them all, as well as being one of the oldest.

Enjoy your flight!

lomapaseo
5th Apr 2010, 00:11
I agree, questions like this are best handled in other forum sections

Short answer for the question is

Not a serious problem even with with one side locked.

Qantas have incidents just like other airlines. The more airplanes, the more incidents.

My advice is to select your airline by virtue of it being approved to fly into countries with strong reguator oversight and by all means by comfort and service.

vapilot2004
5th Apr 2010, 01:53
Wheels locked on one side:
At the higher speeds right after touchdown, pilots have substantial rudder authority available to counter single side locked brakes.

Once wheel braking commences after the nose wheel touches down, main brake application on the opposing side of the failure will even out most of the yawing moment and if needed nose wheel steering can be used to maintain the aircraft's position on the runway.

Capt Claret
5th Apr 2010, 06:29
and their continuing mishaps are a concern

The real concern should be why the media are making so much out of so little.

fredgrav
5th Apr 2010, 08:16
Hey there,
should all the wheels have been locked one side, for sure the anti-skid system would have prevented an asymmetric braking, thus allowing the aircraft to be fully kept on the runway, by using both rudder and thrust reverser. Besides the normal ABS (Auto Brake System), the A380 also has a BTV (Brake to Vacate System) linked to ABS and BSCU: though can't really figure out what would have happened if the anti-skid were releasing pressure on the brakes while the BTV were intesifying the braking pressure just to vacate by the preselected taxiway ...
Didn't study the A380 but there should be a system logic to prevent this from happening.

Cheers,
fredgrav

mrdeux
5th Apr 2010, 08:27
The aircraft aren't fitted with Brake to Vacate.

Taildragger67
5th Apr 2010, 08:31
No.

I have several close family members who fly for Qantas in different capacities.

They regularly happily board aircraft across the Qantas jet fleet (including A380 and 747-400, the types which fly across the Pacific).

Whilst they are happy to do so, so am I. None have a death-wish.

These are minor incidents which happen. The fact that such minor things get reported, indicates there is nothing more serious to report.

fredgrav
5th Apr 2010, 09:16
Hi mrdeux,
what aircraft are you reporting to ? AFAIK BTV is now a default feature on the A380 ...

Capt Claret
5th Apr 2010, 09:42
thus allowing the aircraft to be fully kept on the runway, by using both rudder and thrust reverser

The above excerpt seems to imply the use of asymmetric reverser to assist directional control.

The B717 is the largest aircraft I have flown, all references to directional control and asymmetric reverse, say don't do it. I would assume (dangerous I know) that wing mounted asymmetric reverse would be more difficult to control. :uhoh:

fredgrav
5th Apr 2010, 10:11
Hi captClaret,
surely didn't mean the use of asym reverser, torsion stress ain't well tolerated by the structure at that level, even on ground. Was just saying that, should all the wheels be locked one side, directional control may be assured by rudder, while deceleration by the use of reverse thrust ... that is !

fredgrav

Bullethead
5th Apr 2010, 10:30
Having landed my current aircraft, B767, numerous times with a reverser locked out and an occasional brake locked out I have never noticed any adverse directional control problems, maybe max braking would make the effect more noticeable. No worse than a strong crosswind really.

Regarding the A380, if the two wheels were locked on touchdown it wouldn't take long for them to burst and then the retardation from them would be markedly reduced as the other wheels on the bogie would be supporting most of the weight. I doubt that the asymmetric retardation would cause much of a directional problem and from the vid it appeared the runway tracking was not an issue.

Regards,
BH.

P.S. I spoke to the Captain of the incident aircraft a couple of days ago and he said the landing and rollout felt completely normal until the messages and ground reports started to arrive.

Chris Scott
5th Apr 2010, 11:47
Yesterday, I wrote (see above):
The minor incident you refer to has been covered by PPRuNe on another thread here (http://www.pprune.org/spectators-balcony-spotters-corner/410693-qf32-a380-blows-tyres-landing.html).

Now wish I'd looked at that thread more carefully, before recommending it... :sad:

As we're still here, I'll take the opportunity to agree with Bullethead:
"Regarding the A380, if the two wheels were locked on touchdown it wouldn't take long for them to burst and then the retardation from them would be markedly reduced as the other wheels on the bogie would be supporting most of the weight."

Initially, there would be a tendency to swing to the left, I think. After those tyres burst, this would be greatly reduced. When the pilot applied brakes, the brakes on the other side would be the more effective. This would create a tendency to swing [U]away from the damaged side. All this should be well within the capabilities of the aerodynamics (rudder) and, later, the nosewheel steering.

Chris

vapilot2004
5th Apr 2010, 17:22
should all the wheels have been locked one side, for sure the anti-skid system would have prevented an asymmetric braking

Only if the problem was either upstream of the A/S interrupter valve or not mechanical in nature.

NSEU
9th Apr 2010, 01:11
The minor incident you refer to has been covered by PPRuNe on another thread here.

Anyone who calls it "minor" doesn't know the full details of the incident. Blown tyres are not always minor incidents, and this incident certainly shows it.

I've seen blown tyres before, but never this kind of damage where the wheels and even the brake assemblies were abraded by the runway. I'm surprised the wheels didn't catch fire (or do Airbus 380's have some kind of magical metal alloy which prevents this?).

There were signs of a brake system fault on previous sectors (ECAM message), but the Airbus fault isolation manual obviously doesn't foresee a failure of this nature. All the steps in the manual were followed for that particular ECAM message, but the incident still happened. This is definitely something Airbus will have to look into in the future.

Rgds.
NSEU

Danimal
10th Apr 2010, 12:08
Not exactly A380 related, but reg. the importance of such issues and what possible impact that can cause.

April 1st, a LX A343 had an exploding wheel during taxi (7mph) in HKG on a taxiway towards takeoff. To all surprises, the debris from the right MLG destroyed: all tyres, hit the fuel sensor on #4, almost destroyed the fuel pipe. Besides other pretty hits in the fuselage and elevators. The whole in the ground was impressive, too...
If that would happen during TO or LDG with that ruptured fuel pipe and some sparks, not to imagine. Be assured that Airbus and likely the gear/wheel manufacturers where pretty quickly on site. Not sure, what consequences that will have.
Plane was grounded for a while and is now fixed again.

mrdeux
10th Apr 2010, 13:34
what aircraft are you reporting to ? AFAIK BTV is now a default feature on the A380

As I said...the aircraft is not fitted with BTV.

hottuberrol
10th Apr 2010, 14:29
Good friend of mine was on this flight, a very frequent and global flyer. Said the sparks from the landing gear made for an interesting IFE experience via the external view cameras . The onrush of fire appliances to the aircraft spooked a few people. Otherwise , he classed it as relatively controlled and safe experience.

It took about 2 hours from landing to getting out of the airport while the situation was digested and dealt with; the biggest complaint from some pax was when the cabin crew announced that they could not open the bar :E

ampclamp
11th Apr 2010, 12:15
Enjoy your flt.380 has had some trouble most new aircraft do.And be sure that ALL aircraft and ALL airlines have breakdowns.

the australian press et al are hell bent on making mountains out of mole hills at every opportunity regardng qantas.They aint perfect but still damn good.compared to most out there

Blowing tyres is not desirable, not rare, but unusual in the way it happened.

Forget the hypotheticals.Worrying wont stop anything happening.