Maint error on Airbus A321 and CFM engines. 2

[Alistair_Heaton]

https://assets.publishing.service.g...a63a/AAIB_Special_Bulletin_S1-2020_G-POWN.pdf

Thought some would find this interesting. Not least because it doesn't involve pilot error which is unusual for this level of incident. It was luck more than anything else that both engines didn't stop. Although the FADEC on the second engine will have been in emergency trash the engine mode.

Titan is what we call a white tail airline that only covers shortages in other airlines. They have a pretty good reputation amongst the pilot community, They get audited to hell by multiple organisations away from the official framework due to them being brought in as a wet lease. So all the big carriers audit them to be able to fly their routes at short notice.

Now Kathon is now banned it causes quiet a bit of issues with a lot of the European fleets grounded and parked up in hot places and no fuelling. Perfect breeding ground for the bio stuff in the tanks.

My knowledge on fuel tank quality and testing is limited to draining the tanks for water and signing a bit of paper after I have looked at the moisture test on the fuel bowser to say that its negative.

 

[LittleInch]

Very interesting.

Reminds me of the great Formula Shell fuel additive fiasco of the 1980's when they traced the issue to some fuel terminals adding the additive for the Shell stations by a bucket poured into the top of the road tanker and relied on the general swish of fuel to mix it.

As with this they added too much and didn't mix it properly and then it started burning our inlet valves on certain high mileage vauxhall fleet cars.

I didn't expect they would still be doing the same thing with aircraft fuel though.

I didn't think they have banned the additive, just noted that it needs to be used in the right amounts and mixed properly with an injection pump into a moving stream of fuel.



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[verymadmac]

The absence of an approved Biocide is a quite an operational issue even for parked airliners.

Had a Metro (SA227) with leaking fuel caps, when on preflight they found the "Oil contamination" as they called it, it was promptly biocided, the non drainage low spot in the wing tank still needed the pin hole corrosion cut out and repaired.

 

[Alistair_Heaton]

I would say its more of an issue in the current situation than it normally would be. Tanks are getting a flush through 2-6 times a day when its normal ops. And the bulk fuel temp never really gets above 10 degs for any length of time. Now they are sitting in the sun, no fuel through put.

In EASA ops they have withdrawn its approval which has left no alternative as a biocide.

I believe the FAA has also issued guidance on its usage but I suspect they have a few more options for use as a biocide in the FAA world.

This biocide treatment is something separate to the fuel additives that normally go into jet A when they deliver it. I have zero clue what those additives are. This is to kill the bio sludge growth in the aircraft tanks.

 

[LittleInch]

The key additive is the anti icing or FSII (Fuel System Icing Inhibitor) as they seem to call it now.

Biocide is used on a batch basis and you can get smaller additives for corrosion prevention.

To be left with no biocide seems like a bad move. The tech simply put in far too much of it in a non approved manner ( dumping it in through the top of the tank).

Could easily get some interesting unintentional consequences of this imposed lay off.

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[IRstuff]

Gads, to downed by an "engineer" who doesn't know what "ppm" means.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[Alistair_Heaton]

There was a chain of events as usual and plenty of places that it could of been caught.

The maint manual screw up in LGW could have prevented it as well. If the B1 had access to the proper maint manual system and been able to use the aircraft reg to pull the correct documents he would have run the procedure for the CFM engine instead of the LEAP and that would have made him do a borescope which would have shown the white stuff coating everything.

The calling B1 and B2's in the UK engineers is a national peculiarity. Most other places refer to them as technicians. That said some of them are qualified to BEng level but they tend to be the specialist trouble shooting types/managers.

Its a pretty daft way of expressing a mixture anyway in a manual in my view.

 

[LittleInch]

Well at 100ppm it's not really a "mixture" it's a dosing rate and ppm is very common usage for such additives which are usually metered into a flowing line via a dosing pump. But yes an example of x,000 kg fuel = 0.x kg of addictive would have been useful.

The way they added it in one pour from the top of the tank was not allowed for either as you can't mix it properly and can end up with areas of much higher concentration.

Whilst ppm is commonly volume, I still can't work out how he got to be 37 times the volume. I would have thought it would have been closer to 10 or 100 or 1000. Maybe he inputted litres into a program using gallons or something. who knows?

You would though have thought someone would have checked what and how much he was pouring into an aircraft fuel tanks.

Problems with fuel = planes falling out of the sky so a fairly critical thing to check as far as I can see, even if it wasn't specifically in the manual to do that.

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[Alistair_Heaton]

While I agree with you that its normal in chemical plants its really not in aviation that I have seen.

I think the AMO was Cyprus based so it will be a none native English speaker. And apparently the airbus manuals are not the best having been written in French and then translated into English.

That's the sort of example I am meaning as a better way of presenting it.

I suspect you are correct a unit conversion got into the mix. The bowser will have been recording in litre's. But he could have also taken the tanks at full capacity.

There are multiple ways of this being caught from the stores saying "how much do you want?"

There are certain things that require a dupe signature for work done which means the work is checked twice by licensed technicians, this isn't one of those items. Although that may change.

Anyway in about a years time the full report will come out.

 

[IRstuff]

The report said he found a "conversion calculator," but not whether the calculator was even intended for that calculation

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[waross]

Brings memories of the Gimli Glider.
Another units mixup. Actually more than one mixup.
There was a unit mixup when the tanks were loaded. The tanks were manually checked with a dip stick.
Another unit mixup.
There is an anecdote that a van carrying mechanics from the base in Winnipeg to Gimli to inspect the "Glider" ran out of fuel on the way.
And another memory:
During my time in the Moskito Coast, contaminated fuel was an ongoing problem.
I was often asked:
"Why do you think that this motor won't run?"
My stock answer:
"Probably not enough fuel in the water."
I was right much more often than I was wrong.
In this instance that would be;
"Not enough fuel in the Kathon."


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Alistair_Heaton]

I think its more to do with it coating fairly critical profiles on the internals and also killing various sensors that the FADEC uses to manage the beast.

A similar effect is caused by volcanic ash.

 

[Alistair_Heaton]

FAA SIB on the subject.

https://rgl.faa.gov/Regulatory_and_...86258536005bbe41/$FILE/NE-20-04_Corrected.pdf

 

[LittleInch]

In aircraft fueling and storage / distribution systems additive injection is undertaken on regular basis and people know what ppm means and how to calibrate the injection equipment.

The issue here was trying to add it into fuel already in the tank and not adding it to the new fuel loaded into the tanks.

You get the same problem if a storage tank goes off spec. Trying then to re-circulate though something like a cyclone or a coalescer filter or add some magic chemical can take days and often involves some temporary connections and hoses.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[dik]

Catch the link:

https://www.ncbi.nlm.nih.gov/pubmed/16522539

Dik

 

[Alistair_Heaton]

I used to drive a bowser in a smaller GA airport when I was an instructor, and we never added anything into the load. In fact we had to sign for the load and say nothing had been added while it was under our watch. You did a water check on it and then started pumping it into aircraft. Additional moisture checks were required for some owners of jet A. The biz jets sometimes used to spray something into the tanks while you were filling but you were sacked on the spot if you got involved with that. And the spray was extremely horrible stuff anyway so you kept well clear of it.

I can't remember if there is an injection point on the bowsers feed line. If there is on most of them its not something I was told about.

As a pilot I haven't flown anything that's required additions thankfully its just been x.y tons of jet A please.

What the fuel supplier does with the fuel before delivery I really have zero knowledge of, there is a certificate with fuel receipt that it is within spec outside Europe as well as normally some customs stuff to do with it immediately being exported so you don't have to pay tax on it. Inside EASA land you just get a quantity receipt I presume the QA system deals with the certification of fuel quality.

 

[waross]

For the non-aviation members: Fuel Bowser

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Alistair_Heaton]

That's a special type of bowser that dispenses from a pipe system under the apron.

Certain places the fuel is piped in. Southern England has a pipeline setup to supply "product" directly from the supplier's production site. Other airports have off site bunkers of it and then piped in from there.

Other airports everything is tanker'd in. And the bowsers is a specialised lorry setup with pump and metering unit.

Apart from the bowser on the apron its as close as most get to fuel including technicians. When they pull from tanks it goes into cubes and is then considered dirty. The fuel farm where they fill the apron lorry's is off limits to pretty much everyone. Any fuel spillage and all hell lets loose. And there is a huge finger pointing exercise to avoid paying the fine.

Normally all a pilot will do with pressurised refuelling is set the fuel panel with the quantity that's required and the bowser plugs it and opens up the flow and the aircraft manages the fuelling and distribution from what you have set on the panel, then shuts the valves when its complete. We then take the declared S.G and the ltrs uplift and then do a cross check its sensible. The SG can vary between 0.78 and .82 depending on the fuel temp.

 

[waross]

I used to sit in the plane with the other passengers in Central America while the plane was being refueled.
The fuel truck had two ground cables. Both ground cables were supposed to be connected to the air-frame so that continuity with the air-frame could be proven. The two cables were almost always clipped together and lying on the ground near the air-craft.
Flying in the turd world was often an adventure.
Wrong in so many ways.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[LittleInch]

Most of the anti icing stuff is added as it comes into the airport fuel farm either by tanker or pipeline and then stored in the normally quite small airport tanks.

From there you then either have a hydrant system like the photo or a tanker / bowser which fills up and goes out to the planes.

Once a tank is filled, it is then sealed and tested to meet certain QA requirements. That tank QA note lasts until the tank is unsealed and filled again. You never draw in and out of an aviation tank at the same time. The major test on the fuel is taken at the larger storage tanks either at the refinery or the larger fuel farms befor ebeing shipped tot he airport tanks.

Gatwick (where the incipient took place) is predominantly a hydrant fed system fed by pipeline into storage tanks at the airport. Now whether the fuel transfer truck actually has an ability to inject other additives in ppm amounts such as biocide as required from time to time is not clear, but it should have and would have been a whole heap better than just dumping a load of biocide into the top of the tankand hoping that the normal fuel filling exercise swirled it around enough to properly mix it. Of course adding 37 times more than you're supposed to won't have helped....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.