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ASL Belgium B744 at Nanchang on Aug 24th 2019, rejected takeoff

Started by Jeroen Hoppenbrouwers, Sun, 25 Aug 2019 13:01

Jeroen Hoppenbrouwers

http://avherald.com/h?article=4cbf60db (with photos)

An ASL Airlines Belgium Boeing 747-400 freighter, registration OE-IFB performing flight 3V-820 from Nanchang (China) to Liege (Belgium), was accelerating for takeoff from Nanchang's runway 03 when the crew rejected takeoff at high speed (due to unknown reason). The aircraft slowed safely but became disabled on the runway with 14 of 16 main tyres deflated due to brakes overheat. The crew evacuated the aircraft via the forward upper deck right hand door and slide.

The runway needed to be closed for several hours.

Nanchang Airport reported a total of 127 flights needed to be cancelled as result of the occurrence and blockage of the runway.


martin

"...with 14 of 16 main tyres deflated due to brakes overheat."

Carbon disks (or whatever) is one thing, and rubber another. But even so, one might (perhaps too naïvely) expect that tyres are required to handle such a situation better. Or?
Wouldn't loss of almost all of them in itself create an extra risk, with regard to directional control of the aircraft (on the ground)?

Tyred regards,
Martin


Hardy Heinlin

I guess the tires didn't burst but the fuse plugs opened by design to deflate the tires. Otherwise they would explode due to the hot overpressurized air inside them :-)

And they probably only deflated when the aircraft had stopped as it takes a while until the heat is distributed.


Regards,

|-|ardy

Phil Bunch

I am amazed at how much kinetic energy must be converted into heat during a rejected takeoff with a 747.

That is a lot of joules/ergs/watts/whatever...

As dramatic as it must be to have one's tires catch on fire, I suppose that the proper perspective is that this system was carefully developed and it has also been successfully tested many times with real airplanes and real loads.   

------------
<attempted humor follows:>

Maybe they should instead install something like a large tank of water which would convert the kinetic energy into steam?!  Getting the heat out of the wheel assemblies would be a bit of an engineering challenge...
Best wishes,

Phil Bunch

Martin Baker

Last night I landed a PSX BA config (G-CIVX) at VHHH, Flaps 30, Autobrakes 3 with VRef 144 kts and idle reverse, and got a Brake temperature warning (5). It was lighter than many landings I've done (and flap 30 rather than 25) but I've not seen such high brake temperatures before. What factors would have played into this, do you think? OAT? M

Roddez

Here is a good video of a 777-300ER performing an RTO during testing.
https://www.youtube.com/watch?v=L-by8dZrSJs

The energy/forces in this video are just amazing.

Towards the end of the video, you can see the puffs (carbon brake dust) as the fusible plugs melt and the tyres start to deflate.

To the engineers, how long does it take for a tyre to deflate when the fusible plugs melt? 

Rod.
Rodney Redwin
YSSY
www.simulatorsolutions.com.au

Hardy Heinlin

Quote from: Martin B on Sun, 25 Aug 2019 23:45
Last night I landed a PSX BA config (G-CIVX) at VHHH, Flaps 30, Autobrakes 3 with VRef 144 kts and idle reverse, and got a Brake temperature warning (5). It was lighter than many landings I've done (and flap 30 rather than 25) but I've not seen such high brake temperatures before. What factors would have played into this, do you think? OAT? M

I guess your flight was short, and before the last takeoff you had used the brakes a lot (or your USB brake pedals are always slighty depressed because your feet rest on them and perhaps you calibrated them without a tolerance zone?). -- Or, before the landing, you loaded a situ file that already stores some hot brakes.

The brake temp target values for the left and right wheel groups are displayed on Instructor > Analysis > Miscellaneous.


|-|ardy

Jeroen Hoppenbrouwers

747-400; only the first few seconds of the brake application, but they already glow.
https://www.youtube.com/watch?v=eBRfxiH2voQ

There's also a video somewhere of an A340 test where the fuse plugs were incorrectly installed and did NOT melt... that was quite a boondoggle.


Hoppie

Britjet

It doesn't take much to get the brakes up to 4. Just applying hard braking to make a turnoff will often do it, and in such a situation it's quite usual to see one side hotter than the other, due to asymmetric braking technique or even crosswind. Getting to "5" takes a bit more, but not unusual nonetheless..
When I first started doing pre-flight "walkrounds" I was always struck by how hot it was in the gear area, and I felt a little apprehensive - it took me a while to figure out it was the pack exhaust!
Peter.

Martin Baker

Hardy & Peter,

Thanks for your replies. It was a long flight in fact - from VABB - and I'm sure I don't rest my feet on the brakes :-) so one other possibility that occurs to me is that I thought I selected idle reverse, but didn't. (I have this on a USB axis, so it's not very precise.) This happened to me once before and I think that also caused a higher-than-usual brake temperature. Most landings seem to show 2 or 3, occasionally 4. It's good to know about the target values in the Instructor - many thanks, M