Airbus new multiple failures Landing distance

[longobard]

Hi folks.

something not clear to me with the latest Airbus landing distance calculation method in case of multiple failure, mainly due to the fact that it's not specified if multiple failures (now referred to as "several failures") are really multiple!

A330 exemple:

We have an ENG 1 fail, that's by airbus definition an INDIPENDENT FAILURE. the ecam leads you to shutdown the engine, that leads you to have a subsequent PRIMARY FAILURE (boxed on ecam): HYD B LOW PRESS, plus a number of secondary failures.

my question is, shall I now apply the Several failure landing distance calculation or shall i treat it like a single failure (eng fail)? any reference is appreciated

[Citation2]

As long as there is no "landing distance procedure apply" , there shouldn't be a reason for you to apply a landing distance factor.

Additionaly ,(On A320 family ) In an engine failure , the PTU still supplies the remaining hydraulic system . So your hydraulic system is not downgraded , and your braking capability , and hydraulic systems users are not affected.

Now Imagine an engine failure along with an INOP PTU , there you go , you lost a hydraulic system . In that case you will have to apply a single landing distance factor corrsponding to the affected hydraulic system .

For the purpose of landing distance this is still not a multiple failure (engine failure +1 missing hydraulic !!) as engine failure does not affect landing distance.

[longobard]

citation,

as u can read the example was related to A330 where:

there is no ptu
eng fail leads "ldg dist procedure apply"
a primary failure is involved
secondary failures are also involved

[MD83FO]

QRH PER-C page 2/6 explains it well.

[longobard]

MD83FO,

QRH PER-C page 2/6 doesn't explain if "related and subsequent" failure such ENG 1 fail (A330) and HYD B LOW PRESS (A330) are to be considered as multiple failure or not.

[9.G]

Multiple failures have been removed from the QRH due to the improbability. If need be factoring can be achieved by applying corresponding factors from MEL.
However, it's been reconsidered and Airbus will put it back. :ok:

[longobard]

9.G
multiple failures are already brought back by airbus since march 2014

smash burger
eng fail on 330 have influence on ldg dist

[9.G]

Right you're longobard, the march revision covers the case. :ok:

[nitpicker330]

Interesting as our companies A330 QRH is still 26 Nov 13

We have the list of system failures for each runway condition, pages and pages of stuff.

No mention of multiple failures??

Mmmmmm

[I-2021]

Same here, still working on previous revisions but it's on the way. Longobard (or anybody) can you post a capture of the new QRH ?

Thanks

[rudderrudderrat]

Hi I-2021,

Our A320 QRH only has single system failure Landing Distances published.
If we have a combination of system failures, then we have to use the LPC. (Less paper in the cockpit computer.)

[9.G]

Interesting, it's 11th of June and some operators don't seem to care to update the libraries. LPC is the best solution anyway.:ok:

[Luke SkyToddler]

Longobard my understanding at least as it was presented to me in my last sim, is that all the ECAMs that follow on from the initial engine failure - hyd lo press etc - are all allowed for in the one ENG FAIL landing distance. i.e. it's not a "multiple failure".

That would be reserved for two unrelated failures, like flaps jammed simultaneously with eng fail or something like that.

Out of interest, I was trying to get someone with the March QRH updates in a question I had last month - do you have this new landing distance factor for "overweight landing"? What's your company SOP for applying it?

[Cvk 320]

This is the answer I received from AIRBUS, hope it's clear for everybody .
We reviewed your query and we would like to provide you with the following information:

As mentioned in the FCTM SI-090 “Supplementary Information – Landing Performance”, with the introduction of the In-Flight Landing Distances, it will no longer be possible to combine In-Flight failures (except for some identified cases) using the paper method.

Two main reasons explain this choice:

1. The first reason is that, in terms of figures, the conservatism in the publication of the combination of at least two failures from two different ATA systems becomes too high.

The purpose of the In-Flight Landing Distance tables in the QRH being to be applicable to all operators, whatever the altitude, temperature, weight, speed and wind conditions, it becomes difficult (if not impossible) to publish one single table covering these scenarios without introducing too much conservatism in the final results.
This aspect is all the more relevant than the conservatism has already been increased with the introduction, in the paper method, of additive corrections instead of multiplicative factors.

Knowing that in case of In-Flight failures, over-conservatism in the table might lead the flight crew to choose a diversion rather than landing at destination, we decided to cover in the QRH only some identified combinations for which the conservatism is reduced (e.g. DC BUS 1+2, loss of two brakes, loss of several pair of spoilers, dual hydraulic failure…)

2. The second reason is that, in terms of probability, the combination of at least two In-Flight failures from two different ATA systems is remote.
Historically, this scenario occurred only twice, and in both cases, it was extremely difficult for the flight crew to make an accurate assessment of the aircraft condition to be used for the computation (more than five failures were impacting the landing performance).

Nevertheless, although it is not possible to combine In-Flight failures using the paper method:

• It is still possible to obtain the corresponding performance using PEP or Flysmart with Airbus (in that case, the computation is run for some specific conditions that do not lead to the paper conservatism)

• It is possible, using the paper (and of course PEP or Flysmart), to combine a MEL item and an In-Flight failure, with both of them having an impact on the landing performance. In that case, for the paper solution, the landing factor given in the MEL must be applied to the In-Flight Landing Distance with failure.

We hope this satisfactorily responds to your request. We encourage you to provide us with your feedback using the questionnaire below, and we remain available for any additional information and assistance.

Best Regards,

[Cvk 320]

This is the answer I received from AIRBUS, hope it's clear for everybody .
We reviewed your query and we would like to provide you with the following information:

As mentioned in the FCTM SI-090 “Supplementary Information – Landing Performance”, with the introduction of the In-Flight Landing Distances, it will no longer be possible to combine In-Flight failures (except for some identified cases) using the paper method.

Two main reasons explain this choice:

1. The first reason is that, in terms of figures, the conservatism in the publication of the combination of at least two failures from two different ATA systems becomes too high.

The purpose of the In-Flight Landing Distance tables in the QRH being to be applicable to all operators, whatever the altitude, temperature, weight, speed and wind conditions, it becomes difficult (if not impossible) to publish one single table covering these scenarios without introducing too much conservatism in the final results.
This aspect is all the more relevant than the conservatism has already been increased with the introduction, in the paper method, of additive corrections instead of multiplicative factors.

Knowing that in case of In-Flight failures, over-conservatism in the table might lead the flight crew to choose a diversion rather than landing at destination, we decided to cover in the QRH only some identified combinations for which the conservatism is reduced (e.g. DC BUS 1+2, loss of two brakes, loss of several pair of spoilers, dual hydraulic failure…)

2. The second reason is that, in terms of probability, the combination of at least two In-Flight failures from two different ATA systems is remote.
Historically, this scenario occurred only twice, and in both cases, it was extremely difficult for the flight crew to make an accurate assessment of the aircraft condition to be used for the computation (more than five failures were impacting the landing performance).

Nevertheless, although it is not possible to combine In-Flight failures using the paper method:

• It is still possible to obtain the corresponding performance using PEP or Flysmart with Airbus (in that case, the computation is run for some specific conditions that do not lead to the paper conservatism)

• It is possible, using the paper (and of course PEP or Flysmart), to combine a MEL item and an In-Flight failure, with both of them having an impact on the landing performance. In that case, for the paper solution, the landing factor given in the MEL must be applied to the In-Flight Landing Distance with failure.

We hope this satisfactorily responds to your request. We encourage you to provide us with your feedback using the questionnaire below, and we remain available for any additional information and assistance.

Best Regards,

[nitpicker330]

CVK 320. Thanks for posting that info, I found the reference in my FCTM SI 90.
However some have said their new latest amended QRH does now contain info for multiple failures.

So what is the latest info, your letter or their QRH?

I'm confused ( not hard to do at my tender age !! )

[compressor stall]

How old is that letter? Multiple failure distance calculations reinserted a few months ago. A32F fleet.

[longobard]

CVK 320

thanks for your post but i think that "layers" at airbus changed their mind again introducing methods with the march revision reintroducing the multiple failure paper calculation..


luke

i agree with the fact that a single indipendent failure leading to other primary and secondary failures should be logically treated like a single failure, but still no clarification comes from airbus on this matter

about the OVW, i have no interpretation from my operator. i suppose that the weight correction and the overweight corrections have to be summed.