Another 380 AOG in NRT

[White Knight]

Originally Posted by Marcellus Wallace

Tire Limit speed on the "classic" Airbus is around 195knots...they were not far from that.

I seem to recall tyre limit speed on EK 330/340 as 204 knots; exactly the same as for the EK 380! It used to be around 195 knots on the 'classic' fleet but with Sana'a and Addis I guess Ek went for suped up rubber Many years ago too

[Fratemate]

Apparently they landed with Max Reverse Thrust no Autobrakes(BTV) and used Reversers down to 60 knots or so....would probably have done the same..using the whole runway length.

Not quite true, Marcellus. Look at the video around the 4:00 mark. As they cross A9 they have slowed significantly. At A10 they are down to a speed where, I believe, they could have exited the runway if they wished. They exit the runway at A11, with approximately 850m remaining of a 4000m long runway.

I haven't got a horse in this race and am not criticising the decision making but in a non time-critical situation, such as this, I would be interested to know why they didn't reduce their landing weight further by burning off more fuel, as we've established they could not dump any more and why they did not choose an autobrake level that would have used more of the available runway, keeping the brakes cooler in the process.

A few melted tyre plugs is no big deal, especially as that's what they're designed for, but would it have been possible to avoid even that by landing at a lighter weight and using more of the runway?



(Being a driver of Boeings, I'm taking a punt here that this sort of flap snag is not a time-critcal situation on the Airbus and would welcome advice to the contrary).

[EK380]

Fratemate,

Thanks for the sensible post... Without knowing all details I agree and came to the same conclusion with regards to the taxiways exiting etc...

Again wasn't there on the day, but I personally would have considered A/B OFF.

[bvcu]

just a small observation , BTV and autobrake are not the same, BTV is one autobrake function. Expect all airliners will have it in a few years .....

[glofish]

Now that some calm has set in, may I reiterate my questions?
(all though I love to make the dugong drivers jump and do not particularly like the plane, consider this a genuine interest question!)

- Is there any particular reason as to why such a heavy aircraft can't dump to its MLW? Seeing the consequences of heavy landings and considering that competing models are capable, this seems quite limiting to me.

- Is there not any mention in the FCOM about eventually letting the outfit cool down and the rubbers blow off before going close to gate and other equipment or personel? Without wanting to blame anybody, it seems that having the passengers disembark with all the necessary equipment and people around and basically knowing (through calcs) that some brakes will overheat and some tires might deflate (sounds alarming!) is not the safest option. Again, is there no mention of this in the manuals?

- What use is a BTV if you end up with hot brakes and deflated tires?

[donpizmeov]

Glofish,

Some good questions.
BTV is only usable when all the stuff needed for stopping is working properly, that is, both REVs, all the brakes in normal braking, and a normal flap setting. If any of that ain't working your back to normal autobrake settings (as they did here) which works just like the Boeing one. Think B777 landing BKK some years back.
Overweight landing is thought of in a different light on the bus. And this took some time to get the head around when swapping from the Boeing. As long as the ROD descent is less than 360 feet per minute your basically good to go, with minor inspections. On the 380 if within 60T of MLW all you have to do is look at some software and burn the results to DVD, no engineer required. If over 60T the same software shows if and what inspections are required, its not as big a deal as the ACARS after landing on the Boeing.
Because of this Airbooooose decided to keep the fuel system simple, so each engine has 20ishT feeder tanks that can't be dumped. Even at max ZFW if you dump everything you should get close to the 60T about MLW. When fueling, some computer pumps the Fuel around the different tanks to get the Cof G to 39.5%, so if you haven't got full fuel, you mightn't have full feed tanks for takeoff. As a general rule of thumb, if you don't need to reduce weight due to performance, you don't need to dump.
Precautions due to hot brakes are pretty much the same for all aircraft. As tyres are tyres.

This crew made their best decision with the information, and experience they had at the time. Its very easy to say that you would have done something different when already knowing the outcome.

The Don

[glofish]

Thanks don, explanation makes some sense.

I didn't pretend I would have done something different though, I actually only raised questions as to why.

And finally sorry Mr.Ex-Super for my blasphemy to pretend the dugong had anything close to a competitor ....

[Fratemate]

Is there not any mention in the FCOM about eventually letting the outfit cool down and the rubbers blow off before going close to gate and other equipment or personel? Without wanting to blame anybody, it seems that having the passengers disembark with all the necessary equipment and people around and basically knowing (through calcs) that some brakes will overheat and some tires might deflate (sounds alarming!) is not the safest option. Again, is there no mention of this in the manuals?

Glofish,

You're making way, way too much of the fuse plugs melting. They do so with a fart and a Texan whisper. There's no huge explosion. There's no whirlwind of air whipping fire appliances off their wheels. There's no huge settling of the aircraft on its axles. As with all hot brakes, you stand in front or behind them and you don't spray liquids onto them. You let nature takes its course and see if they cool quicker than the plugs melt. If the plugs win, then the tyres deflate. No big deal and alarming only if you're a big girl. I would much rather have the passengers de-planing as EK did in this instance, than parking out in the middle of NRT's taxyways, with the attendant flashing lights and nonsense that only the Japanese know how to excel at.....now that, for the pax, is alarming.

How do you stand on the 757 having no fuel dumping facilities at all? That can take off way above its MLW and, shock, horror, it can land (in emergency) above its MLW. You'll be amazed to know this is the case for all modern airliners, so stop trying to have a dig at the Airbus. I stand by my question regarding the crew's decision to reduce their weight by burning off fuel but this is a genuine query, rather than an uniformed dig at an aircraft manufacturer.

[donpizmeov]

This JAARule fella sounds like a well balanced individual. A true enthusiast.

The Don

[glofish]

@Fratemate

How do you stand on the 757 having no fuel dumping facilities at all? That can take off way above its MLW and, shock, horror, it can land (in emergency) above its MLW. You'll be amazed to know this is the case for all modern airliners, so stop trying to have a dig at the Airbus

I’m amazed about your knowledge, thanks for sharing it. But I will always have a dig at Airbus, as I will at Man City and Schumi (might there be a pattern??).

Joke aside:

(My take:I would always prefer the aircraft that allowes me to land with lower weights in abnormal situations. It’s simply added safety and that’s something I like!)

When QF32 flew around for 2 3/4h, completing 52 ECAMs, but mainly to get down to a decent weight because it could not dump (technical), I asked why on earth would a crew fly around so long, with one donkey exploded, two others not reacting, the cg slowly moving out of green and to top it, a hole in the wing, the award giving Airbus communitiy told me that this was the best and safest option. No danger in staying up with that injured animal, it was way better to get the weight down in view of the abnormal conf landing in spe.

(My take: I would always prefer to get a wounded animal on ground asap, especially if the extent is not completely known and deteriorating.)

Now I learn that even without technical, the 380 can’t dump to MLW. Taking the above argument now, I then asked, if such a missing feature makes sense! But now suddenly there seems to be no problem with the heaviest airliner landing overweight with abnormal conf and hot brakes and melting fuses, all allowing a normal taxi to the gate and disembarkation.

I know, it’s Monday morning quarterbacking. But don’t we learn by doing this? Can’t we oppose a different strategy to what another crew chose, on a rumor forum? Can’t we question design without getting the groupies all upbeat?
Even if it concerns the wholy 380 and Airbus.

And finally, if we can’t keep up the teasing and getting the girls throw their handbags, where’s the fun on this site?