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-   -   A350 engine shutdown incidents linked to cockpit drink spills (https://www.pprune.org/rumours-news/629315-a350-engine-shutdown-incidents-linked-cockpit-drink-spills.html)

Dave Therhino 5th Feb 2020 16:42

EASA just issued an emergency AD on this. 2020-0020-E dated today

Dave Therhino 5th Feb 2020 16:46

https://ad.easa.europa.eu/ad/2020-0020-E

Airbubba 5th Feb 2020 17:31

Looks like the original poster's rumor was essentially correct. :ok:

From the emergency AD:


Two in-service occurrences were reported involving inadvertent liquid spillage on the ENG START panel or ECAM Control Panel (ECP) on the centre pedestal in the flight deck on A350 aeroplanes. In both cases, the aeroplane experienced an un-commanded engine in-flight shut-down (IFSD) of an engine some time after the liquid spillage. Subsequent engine relight attempts were not successful. In both events, the flight crew performed a diversion and landed the aeroplane safely.

Results of the preliminary technical investigations indicate abnormal operation of the components of the ENG START panel or ECP due to liquid spillage in the system.

This condition, if not corrected, could lead to a dual engine IFSD, possibly resulting in a forced
landing with consequent damage to the aeroplane and injury to occupants.

To address these occurrences, Airbus published the applicable AFM TR defining a liquid prohibited zone in the cockpit, and the procedures to be followed in the case of inadvertent liquid spillage on the centre pedestal. Airbus also published the FOT, reminding operators about the standard practices for handling liquids in the cockpit to reduce the probability of hazards.

For the reasons described above, this AD requires amendment of the AFM.

blind pew 6th Feb 2020 02:03

Hard to believe the incompetence
 
Used to a regular shower during descent from the ceiling condensation running forward..IIRC on the VC and DC 10s without any problems bar a light soaking. So what’s wrong with the modern designers?

jugofpropwash 6th Feb 2020 03:31


Originally Posted by Airbubba (Post 10680252)
Looks like the original poster's rumor was essentially correct. :ok:

From the emergency AD:
To address these occurrences, Airbus published the applicable AFM TR defining a liquid prohibited zone in the cockpit, and the procedures to be followed in the case of inadvertent liquid spillage on the centre pedestal.

Are they planning to provide a bag of rice to dump in there to soak up the moisture? Or perhaps a blow dryer?

Crosswhinge 6th Feb 2020 04:36

I saw the film and only as the end credits ran did I see the name. A disgraceful.

Twitter 6th Feb 2020 05:59


Originally Posted by blind pew (Post 10680602)
Used to a regular shower during descent from the ceiling condensation running forward..IIRC on the VC and DC 10s without any problems bar a light soaking. So what’s wrong with the modern designers?

There is a difference between condensed water, which is more or less pure water - and drinks of tea, coffee or orange juice - which contain sufficient impurities better to conduct electricity.

As for modern designers, as noted above, a DC-8 orange juice spill proved able to kill a lot of avionics in those good old days. However, increased reliance on electronics for system switching means vulnerability of more flight important systems (engines) to the threat.

NWA SLF 6th Feb 2020 17:36

I cannot comprehend making portions of the cockpit liquid free zones and #@$# happens. Recall pictures of cabins after severe unexpected turbulence where debris is scattered cabin wide. The cockpit needs to be liquid free period or design specialized containers that are completely leakproof unless in the person's mouth ala containers developed for space. I fail to comprehend how pure condensation water will not be a problem as water flowing over materials will collect contaminants. Even dust can do the job. Will Delta and Airbus support the obvious aviation film to result from this event? Is a large portion of the A350 fleet now grounded due to Coronavirus or have they been repurposed? I'm thinking of my home airport MSP and their A350 to Shanghai but there are so many Delta A350 flights from DTW and ATL.

wiggy 7th Feb 2020 07:32


Originally Posted by Airbubba (Post 10680252)
Looks like the original poster's rumor was essentially correct. :ok:

As I read it (correct me if I am wrong) ATM the reality is a formal ban of transfer of liquids over the centre console and a reminder that drinks should be passed around the outside of the seats, something most of us have had in company SOPs for years..I don't see that as being essentially the same as "a banning all liquids and fluids from A350 flight decks"

Fursty Ferret 7th Feb 2020 07:42

Perhaps a good start would be to mandate spill-proof cups in the flight deck? I find it frankly astonishing that at my company drinks are served in open mugs or paper cups without lids. I bought my own reusable mug with a lid.

Tech Guy 7th Feb 2020 10:49

https://cimg8.ibsrv.net/gimg/pprune....d304d1eb0b.jpg

Daniel_11000 7th Feb 2020 14:17

One can ask why maintenance people are required to attend regularly EWIS initial/recurrent courses,
when instead a/c are designed with such poorly engineered connectors ! How can Authorities have passed such
a design standard ? Why EASA tries to correct with an AD amending the AFM ?

jugofpropwash 7th Feb 2020 16:32


Originally Posted by Fursty Ferret (Post 10681532)
Perhaps a good start would be to mandate spill-proof cups in the flight deck? I find it frankly astonishing that at my company drinks are served in open mugs or paper cups without lids. I bought my own reusable mug with a lid.

Seriously. Spill-proof travel tumblers can easily be had for under $15, and I'm sure they'd be even cheaper bought in bulk. I believe a number of offices/schools require them for working around computers. No reason for the airlines not to stock those in the galley for use on the flight deck. Certainly a lot cheaper than a diversion and repairing wiring.

Herod 7th Feb 2020 19:01

My old airline had the "sippy-cups" way back. I left in '03, so they must have come in very early in the century, at the latest.

tdracer 7th Feb 2020 21:08

Over my ~40 year career in Propulsion, there were a lot of "unintentional" engine shutdowns, for various causes. Switch confusion (actuating fuel switch instead of the EEC switch - resulting in the relocation of the EEC switches to the overhead), fuel configuration or fuel pump errors, even accidentally snagging the fuel switch with clothing while reaching for something else. I never heard of one related to a drink spill or other liquid contamination.
In short, this is a pretty serious miss by Airbus - something that should be designed for at a very basic level.
Something tells me the tone of this thread would be quite different if this had happened on a 787 instead of an A350...


For the reasons described above, this AD requires amendment of the AFM.
That'll almost certainly be an interim step to mitigate the problem, while Airbus comes up with a permanent solution that corrects the fundamental problem - which will then get it's own AD.

cashash 7th Feb 2020 21:13


Originally Posted by blind pew (Post 10680602)
Used to a regular shower during descent from the ceiling condensation running forward..IIRC on the VC and DC 10s without any problems bar a light soaking. So what’s wrong with the modern designers?

But on the VC10/DC10 you had hard-wired switches that were a lot less susceptible to shorting out. On modern aircraft you have electronic switch panels that are as delicate as any other IC.

I cant see that making specific zones of the Flight Deck 'drinks free' is going to solve the issue as you are always going to get the odd clown who leaves the window open just before a storm arrives. So how about waterproofing the switch panels of safety critical systems? - if they can waterproof your cellphone then it should be fairly easy to incorporate on the flight deck.

Lord Farringdon 9th Feb 2020 07:12

Early in this thread I could not believe that this had actually happened ie a spilled drink had caused an engine shutdown and that all attempts to restart it failed. Now I see this is actually true. So in the absence of any contrary argument, I logically conclude that if the ingress of liquid could cause one engine to fail then quite possibly it could cause two engines to fail, neither of which may be able to be restarted. . Just a small issue then that a simple AD to how we drink coffee and water will fix while we are still flying passengers in these things. I mean, maintenance will never leave the window open when one of those tropical storms lashes through will they? No chance of a cleaner spilling their spray 'n' wipe. No chance of turbulence.......

The risk of a major disaster in a certain other manufacturer and there would good cause for a grounding until we knew more about the problem.

KelvinD 9th Feb 2020 07:39

I once had an amusing experience on a VC10 involving condensation.
I was travelling from Tokyo, via Hong Kong to Colombo and Seychelles, sometime around 1978/9. At Hong Kong, we were all ready to go and the aircraft was quite full, with only one vacant seat. A rather large American guy boarded as the last passenger and as he walked down the aisle toward that one remaining seat, he was bitching and moaning in a very loud voice about there being no hotel rooms in Hong Kong so he had to get out of there. He really was an annoying so and so, doing a good impression of the stereotypical "ugly American". (No offence intended toward Americans here, but anybody who saw and heard this guy would know exactly what I mean).
Anyway, off we trundled, resuming our journey. As we lifted off, there was an anguished cry from the American of "Has anybody got an umbrella?" There was a huge stream of water pouring from the area of the overhead bins straight down the back of this bloke's neck! It was quite a sight and the only place in the cabin where there was a waterfall. And, as the aircraft was climbing quite steeply, the wet passenger was unable to move from under the stream and had to put up with what seemed a couple of gallons down the back of his neck. There were amused smiles all around from the crew and one or two passengers mentioned there was proof there is a God. To his credit, once it was all over, the American bloke had the good grace to say something to the effect of "Well, that'll teach me. I shouldn't have started off with my bitching and moaning".

Twitter 10th Feb 2020 12:59


Originally Posted by KelvinD (Post 10683120)
I once had an amusing experience on a VC10 involving condensation.
I was travelling from Tokyo, via Hong Kong to Colombo and Seychelles, sometime around 1978/9. At Hong Kong, we were all ready to go and the aircraft was quite full, with only one vacant seat. A rather large American guy boarded as the last passenger and as he walked down the aisle toward that one remaining seat, he was bitching and moaning in a very loud voice about there being no hotel rooms in Hong Kong so he had to get out of there. He really was an annoying so and so, doing a good impression of the stereotypical "ugly American". (No offence intended toward Americans here, but anybody who saw and heard this guy would know exactly what I mean).
Anyway, off we trundled, resuming our journey. As we lifted off, there was an anguished cry from the American of "Has anybody got an umbrella?" There was a huge stream of water pouring from the area of the overhead bins straight down the back of this bloke's neck! It was quite a sight and the only place in the cabin where there was a waterfall. And, as the aircraft was climbing quite steeply, the wet passenger was unable to move from under the stream and had to put up with what seemed a couple of gallons down the back of his neck. There were amused smiles all around from the crew and one or two passengers mentioned there was proof there is a God. To his credit, once it was all over, the American bloke had the good grace to say something to the effect of "Well, that'll teach me. I shouldn't have started off with my bitching and moaning".

VC-10 was originally designed with a large (and heavy) water tank and humidifying system. Bean counters loved it not overly - so it got removed. Maybe your talkative fellow pax caught the dregs?

At least the Conways kept going - that’s progress.

Electronics Pro 10th Feb 2020 20:09

Electronics design error
 
Hello all,

As an experienced electronics engineer I have to say the there are many electronics design errors when interfacing modern digital electronics, especially with the digital inputs.

Typically a digital input (ON/OFF) input is implemented by using a pull-up resistor and a grounding switch (or a pull-down resistor with a switch to voltage).

I believe that A350 engine control digital inputs have too high impedance. The control inputs should not change the state with coffee or other liquid spilled on/in the the switches. This applies to all reliable electronics design.

Moisture or any liquid stuff can cause leakage current between any terminals. But if the design is robust (ie impedance is low enough) there is no effect in the ON/OF state because a possible leakage current is minimal compared to the intended ON/OFF signal. If a pull-up design is used the pull-up resistor value should be low enough to win a possible leakage current caused by some liquid.

Furthermore, all the input circuitry, switches etc should be tested with high humidity and with possible liquid spill.

I hope Airbus engineers, and all other manufacturers are reading this, because this is extremely critical and it can't be solved with software!

Best Regards,
A concerned electronics engineer/private pilot in Finland


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