SATA brand new A320 ; hard landing in Lisbon

[45989]

I'd say the G load was only a sideshow in the context of the expletitves from the encampment near Mullingar!
More to the point are the two still even there, given the culture that seems to exist in that organisation?

Got ryr the unenviable distinction of the first Irish airline operated jet hull loss ever

[esmifra]

4.8 g

The hard landing achieved 4.82 G´s. The maximum permitted was 2.6 G´s.
The AC is doeing a deep inspection in TAP Air Portugal.

[aDriver]

I always understood that the design landing limit equated to a touch down at 1000ft per/min at max weight + proof factor.

This equates to an unflared landing after a 3 degree glide path with the max permitted tailwind.

[A4]

@IGh

You are correct regarding the A300's and A310's...... but they are not FBW aircraft. If I recall these events are similar to the Iceland B757 i.e. fighting the THS/trim.

Whilst it is possible to make a horlicks of any go-around, the current FBW family of Airbus products do provide a great deal of protection. Go around in an (current) Airbus is straight forward..... push the levers to TOGA and either let the A/P do the work or just pitch to SRS and engage the A/P. Simples! If in the excitement you over pitch then the protections should help you.

There was an A330 loss during a test flight at TLS during a go-around.... can't remember the details but I think it involved a simulated engine failure during the go-around/ altitude aquire (ALT*) phase with insufficient altitude to recover

A4

[akerosid]

An update to the Aviation Herald entry on this incident says:

"Portugals "Gabinete de Prevencao e Investigacao de Acidentes com Aeronaves" (GPIAA Aviation Accident Branch) told The Aviation Herald on Aug 21st, that they are not investigating the occurrence."

NOT investigating the occurrence? Can't understand why not; I'm presuming the GPIAA works under the same rules as the AAIB and the AAIB certainly would be, particularly given allegations that the aircraft may have flown another sector following the incident.

[fc101]

IGh,

I think most of the comments regarding Airbus are references to its control laws and the FBW philosophy and then meaning the 320, 330 and 340s. Your examples are for the A300/310 which are more "standard", whatever that means.

This thread is (should be) more about a hard landing in an A320 rather than an unstable approach in a 757.

But please let's not turn this thread into an AvB

fc101
E145 driver

[HarryMann]

I always understood that the design landing limit equated to a touch down at 1000ft per/min at max weight + proof factor.

16.6 ft/s - I'd say that sounds about right for an extreme liimit

12~15 ft/s is normally what's quoted

The vertical speed and weight limits, are more a measure of the kinetic energy absorption of the u/c. beyond that G ^ rapidly and is not directly calculable

4g at 15 ft/s implies a very small deceleration displacement (6" to 9"), implying the u/c has already done the best it can and we are into plastic deformation territiry

Very surprised indeed if 4.6 G recorded and that deep inspection doesn't find damage

[HarryMann]

PS. There is a big difference between wingborne G loads (+6/-3) and a landing impact.
The former involves primarily udls (uniformly distributed loads), airframe pressures often largely mitigated by inertia.(alleviation)
The latter more like point loads exacerbated by inertial considerations.

The whole story cannot be told by a single 'g' figure, as John Farley said quite way back. But a central body 'peak G' does give a comparison figure, and thus a measure of likely structural damage..

[BOAC]

I have exhausted 'search' and cannot find it, but there was a ?330? thread a while back about a heavy landing which grounded the a/c for weeks with major u/c mounting damage I think - Manchester? Anyone recall?

[G-BPED]

Originally Posted by BOAC

I have exhausted 'search' and cannot find it, but there was a ?330? thread a while back about a heavy landing which grounded the a/c for weeks with major u/c mounting damage I think - Manchester? Anyone recall?

I believe this is the thread you refer to http://www.pprune.org/rumours-news/2...nding-sfb.html

Aircraft was ferried back from SFB to MAN for repairs

Regards,
G-BPED

[NARVAL]

From my recollections (not yet hazy...) it is not the first bounce, on a "hard" landing, that causes the excessive acceleration and damages the plane, but the next more or less controlled landing (or crash landing)...I was always taught, if after a miscalculated flare, the plane really bounced back into the air , to GO AROUND, forgetting any pride. If not, Airbus tells not to try to flare again, but to wait with sidestick in the neutral position, and control the descent with a little thrust, but insists you should go around. I do not know if this was the case here, but after bouncing, trying to soften the next touchdown with stick back, decaying speed, nose very high, leads to catastrophic impacts. But you all know that...just to show I am not napping...The A330 at Toulouse was a take-off and another matter completely.

[esmifra]

Some rivets disapered and others found loose.

[BOAC]

Thanks G-BPED - that appears to have been 2.7g, and both imain gear replaced.

[PJ2]

NARVAL;

it is not the first bounce, on a "hard" landing, that causes the excessive acceleration and damages the plane, but the next more or less controlled landing (or crash landing)...I was always taught, if after a miscalculated flare, the plane really bounced back into the air , to GO AROUND, forgetting any pride.

That is precisely correct both tactically (SOPs), and as seen/experienced.

[Dani]

I would strongly agree with Narval. It would be very difficult to obtain a 4.6g if you try to fly the aircraft into the ground. It usually happens when the aircraft pops up into the air again, looses lift, stalls and "falls" on the runway. The situation can be seriously aggravated if the lift dumpers extend after the first bounce and destroy even more lift.

Dani

[PJ2]

Dani;

Yes, fully agree.

So then - do we know, officially, whether this airplane flew after the hard landing or was it grounded?

[esmifra]

Flew. The hard landing wasn´t at Lisbon.

[lurkio]

BOAC, not sure if this was the thread you referred to, but it was a TCX 320 at BRS which ended up in MAN hangars. I am typing from memory as I have not re-read the thread but hopefully this is the link.

http://www.pprune.org/rumours-news/2...par-crack.html

[BOAC]

Thanks for that, lurkio- could not see a g estimate there though.

[krujje]

Quote:
What's the max "g" loading that an A320 (or indeed any commercial acft) can have on landing without structural damage?
Airliner airframes structural mininums are:

Up 3G
Fwd. 9G
Down 6G
Laterally 1.5G

Just a small clarification on this:

The above quote is referring to § 25.561 of the FARs. That requirement is about aircraft crashworthiness. Aircraft structure is not designed to withstand those levels without damage. The requirement is that the aircraft structure be designed to give each occupant every reasonable chance of escaping serious injury in a minor crash landing. The acceleration levels quoted above are those felt by the occupants. In addition, the attachments for items of mass in the aircraft which cannot be positioned so that, if they break loose, they do not injure occupants, pierce fuel tanks, or block emergency egress, must also be designed for those acceleration levels.

So, for example, the mounting system of the APU must be designed to withstand the loads produced by those inertia levels applied to the mass of the APU. Otherwise, in a "minor" crash landing, there is a risk that the APU breaks loose and causes hazards for the occupants of the aircraft.

I always understood that the design landing limit equated to a touch down at 1000ft per/min at max weight + proof factor.

§ 25.473 "Landing load conditions and assumptions" specifies 10 fps at design landing weight, or 600 fpm, and 6 fps at maximum take-off weight, or 360 fpm. Aircraft structure is designed so that no permanent deformation occurs at the maximum loads induced by these landing conditions, over a range of aircraft mass distributions, landing attitudes and landing speeds. The structure is designed not to fail (although permanent deformation can occur) for loads up to these maximum (limit) loads mulitiplied by an ultimate factor of 1.5. In addition, the landing gear itself is tested to reserve energy conditions (§ 25.723), a 12 fps descent rate at design landing weight, which corresponds roughly to the ultimate factor of 1.5 (12^2/10^2 = 144/100 = 1.44). The landing gear structure is designed not to fail up to the reserve energy condition.

It's important to note that the FARs allow the manufacturer to make the assumption of 1g wing lift in the load calculations. Therefore, the 10fps and 6fps landing descent rates are steady-state conditions. In bounce situations, with lift dump deployed, the aircraft can land considerably harder than it was designed for, due to the lack of lift on the wings.

It's also important to note that not all of the aircraft structure will be designed by landing loads. Many flight load cases are more critical.