AF66: explosion of a GP7200 reactor on Airbus A380 over the Atlantic

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lemontval
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by lemontval » 07/10/17, 08:36

Morality, let's stay on the cows floor !! : Lol:
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by Did67 » 07/10/17, 09:36

Christophe wrote:
Once again, congratulations to the airbus engineers! ...


Yes, I have the impression that there were not many calculation errors in the structure ...

I had seen a report on the tests before certification of the A380. And he was mistreated in all extreme situations: the highest airport in the world, the freezing, sandy wind I don't know where, etc ... And I saw the tests in Reykjavik when the airport was closed due to storm, with crosswind landings with the plane landing at an angle of maybe 30 ° to the runway ... But it was a "calm" wind (not turbulent, no 'shear effects), it was "enough" to put the rear axles on the tarmac, then straighten up to get in line with the rudder before placing the front wheels ...
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by Did67 » 07/10/17, 09:40

In the same series, research the spectacular landings in Funchal (Madeira). It is one of the most turbulent civil airports in the world. You will not be disappointed !

Me, on the contrary, it "vaccinates" me: when you see that and you know that there was no crash, you don't worry about a few jolts in an approach phase (I was shaken once, recently, in Basel, landing in full thunderstorm, and once severe in Bamako, take-off in full tropical storm, with thunderbolt at the end of the wing on the 727, the plane which "slalom" during its launch phase!).
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by Christophe » 07/10/17, 13:58

Did67 wrote:Yes, I have the impression that there were not many calculation errors in the structure ...


Uh it is not an impression it is a fact!

When you know that the 747 (which is still one of the best long haul in the world ... if not the best) was originally designed with a slide rule and a drawing board (no computer in the 60s ... or extremely rudimentary ...) ... well, it's perfectly normal for an airplane designed in the 2000s not to be subject to structural calculation errors! !

It would be a shame ... really ...

Then there are physical limits: I don't think the A380 could have landed with a side wind of 200 km / h for example, since the force is squared by the speed (in m / s) and that at 140 it was already limited ... in this case we divert them ...

You can find on Youtube some beautiful "crab" landing with planes which may be a little less "assisted" than the A380 ... in 2014 I was in Corsica during the Air France strike, we returned with a 737 d 'an Eastern European company which must have been 25-30 years old ... and therefore necessarily less assisted than an aircraft designed in the 2000s (even if some planes can be "upgraded" ...)

Gaston will surely have an idea of ​​the certification "admissible landing crosswinds" ...
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by Did67 » 07/10/17, 14:13

As far as I know, I believe it is "the scissors effect" that is the big fear. And it is unfortunately, difficult to predict ... I have the impression that this is kind of what happened ...
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by Gaston » 09/10/17, 10:09

The general rule is that an airplane must be able to withstand a crosswind of 20% of its stall speed.

For an airliner, the stall speed is around 250 km / h, so it can withstand a wind of around 50 km / h perpendicular to the runway.
Note that we only measure the perpendicular component, it can be a wind of 150 km / h with an angle of 20 ° relative to the track or 100 km / h at 30 °.

This is why many airports have several runways with different orientations to minimize the perpendicular component of the wind.
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by Christophe » 09/10/17, 18:54

Thank you Gaston!

Only 20% of its stall speed? It's not much, but does that mean that the plane can withstand these 20% "without flinching" then? I mean in complete stability and without having to do special procedures?

The above case of the A380 in Düsseldorf is well above this value of 20%!

Otherwise when you are close to the ground, a side wind coming with a "tail" component is much more dangerous than a front side wind. We can therefore understand fairly well that this 20% is a very low value (and therefore very secure) ...
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by chatelot16 » 09/10/17, 19:41

if there is no handicap of the coat at the control tower, they will choose the direction of the track where the crosswind is rather from the front than from behind ... and if the wind turns in the wrong direction during a landing attempt the control tower will advise to go around

problem when there is bizarre wind the wind does not have the same direction everywhere ... it can be in one direction for the wind vane of the tower and be different on the track

another remark is the pilot who is master on board ... it is he who chooses if he can land with conditions exceeding the standards ... it is the pilot who chooses if he prefers to make a somewhat risky landing immediately rather than divert and make another landing even more risky without the possibility of going back because more fuel

it is the pilot who knows if he is capable of making a landing at the limit of the plane's possibilities
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by Did67 » 10/10/17, 10:49

Airports with runways with different orientations are not the rule, however. These are the very large hubs. So in general, in fact, there remains just the choice of the direction in which the plane takes the runway. By perpendicular wind, that does not make much choice ...

There, in Düsseldorf, I have the impression, given the movement of the plane, that it was caught in a whirlpool just where it landed. Hence a purple blow to the right, then a violent blow to the left of the tail of the plane ...

I understand that there are very specific weather radars which detect the risk of such shears on the most exposed airports. I don't know if Düsseldorf has one. But such a vortex can be created in a few seconds in the final landing phase whereas before, everything was still within limits and the CDB made the decision to land ... I saw a video where in Funchal a twin-engine (like Airbus A320) is "caught" like a dead leaf when it was about to put its rear wheels, not without difficulty on the runway and not beside it, to finally set off again (probably full throttle) ...
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Re: AF66: explosion of a GP7200 engine on Airbus A380 over the Atlantic




by Christophe » 10/10/17, 11:19

chatelot16 wrote:problem when there is bizarre wind the wind does not have the same direction everywhere ... it can be in one direction for the wind vane of the tower and be different on the track


I think that most modern international airports have fairly precise wind sensor networks (undoubtedly ultrasonic probes) and it is surely not a single wind vane which gives the winds on the runways (we are more in the 30s huh ...) ...

The concern of all pilots on landing (it means with a low flight height) is the inconsistency of the wind, in other words the gusts ... especially that by downwind ... these are the most dangerous (sudden loss of altitude)

The majority of accidents in paragliding or paramotor on landing come from back gusts which cause a sudden drop in the "height to the ground" ... or rather a brutal acceleration of the ground Vz (in negative obviously). It happened to me once, luckily without too many serious consequences.

At 50m high it is not a concern to lose 5m ground in less than 1 second, at 5m it becomes one ...

Another big concern is the Residual vortexes on the runway (reactors and wings): a 747 taking off it takes more than 5 min for a small single-engine aircraft (Cesna or Diamond type ...) to be able to take off safely on the same runway. For larger planes it is less problematic but these phenomena when they are amplified have already led to crashes or serious incidents.

This has had the effect of some studies ...
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