A321 AAIB Report: Mayday/emergency landing due to fuel additive error

[slfie]

As reported on the BBC: Plane engine stalled and caught fire after 'engineer's fuel error' (https://www.bbc.co.uk/news/uk-england-sussex-52379192) (there's a link to the AAIB bulletin).

An A321 taking off from LGW on 26th Feb had engine problems at 500ft, leading to a Mayday call and emergency landing. Fortunately not a bad outcome, but it must have been an exciting few minutes.

[Dave Gittins]

The bit that surprises me is that an aircraft engineer did not know what PPM meant and apparently Googled it without finding out its proper meaning.

As usual with the press there is no recognition, and probably no understanding, of the difference between a flame as result of a surge and "caught fire".

Fortunately, as it happened just after midnight, there were no schools occupied.

[esscee]

So what "comedian" of an engineer did it then? Which company and who/where was the supervisor? Talk about basic error! Should not be working on aircraft, take their licence away, if they had one!

[cashash]

I can see how the guy made a mistake with regards to the PPM what I think is of larger concern is that he seems unaware of how to use Airnav properly.

[TheReverend]

The bit that surprises me is that an aircraft engineer did not know what PPM meant and apparently Googled it without finding out its proper meaning.

As usual with the press there is no recognition, and probably no understanding, of the difference between a flame as result of a surge and "caught fire".

Fortunately, as it happened just after midnight, there were no schools occupied.

And the press interpreted "A "stall" message was displayed in the cockpit three times" to mean the second engine stalled. I'm assuming the stall warnings were due to low-airspeed and high AOA.

[eglnyt]

By my reading of the AAIB Bulletin the guy who made the mistake on the concentration was not the one who had trouble using Airnav. Seemingly two different organisations. But you are right there are other things in there potentially of larger concern than the additive concentration error.

[Webby737]

It was two different guys from two different maintenance organisations involved in this.
I'm surprised that a B1 Engineer wouldn't know what ppm meant, but it's really scary that the engineer at LGW was unable to use Airnav, pretty much everyone I know and have worked with can happily switch between Airnav and AirnavX. (personally I'm not a fan of AirnavX).
It's quite easy to screw up the effectivity in the A330 & A340 manuals in Airnav but this is due to the different weight variants, the A320 should be fairly straightforward so I've no idea how he ended up using a manual for a NEO.

[WHBM]

Although the report does not explicitly say so, it does say at the start that it is circulated to the Cyprus authorities, otherwise seemingly uninvolved. Later it states the aircraft went to an un-named AMO in late January for a major check.

G-POWN is shown on FlightRadar as positioning Stansted to Larnaca on 20 January, no information until returning same route on 24 February. The incident flights occurred the following day, 25 February.

[Webby737]

I know who did the heavy check in LCA (we did some work on that aircraft for them) but I've no idea who was looking after the line maintenance in LGW.

[cashash]

Thanks guys - on re-reading I see now that the Fuel additive procedure was done at an AMO in Europe and only the troubleshooting was done at LGW. So 2 basic errors on the same snag by 2 different engineers - what are the odds on that?.

[gearlever]

"Plane engine stalled and caught fire"
No fire.

Titan A321 at London on Feb 26th 2020, left engine surged, engine stall indications for right engine (http://avherald.com/h?article=4d42d3b7&opt=0)

[DaveReidUK]

Thanks guys - on re-reading I see now that the Fuel additive procedure was done at an AMO in Europe and only the troubleshooting was done at LGW. So 2 basic errors on the same snag by 2 different engineers - what are the odds on that?.

It may or may not be significant, but the FR24 ground track for the positioning flight back from maintenance at LCA started from outside the Bird Aviation (https://www.birdaviation.com/) hangar.

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/830x670/bird_aviation_9fc46195dc93c81edf2e9a14c122ed535d70e4af.jpg

[lomapaseo]

Are we sure it was caused by a fueling error?

Were any official investigators involved complete with causes effect documentation?

[ivor toolbox]

Are we sure it was caused by a fueling error?

Were any official investigators involved complete with causes effect documentation?

Er, the AAIB is UK equivalent of US NTSB,
the answer is yes to both your points, you might want to go back to the spotters balcony now and leave further discussions to grown ups

[DaveReidUK]

Are we sure it was caused by a fueling error?

Were any official investigators involved complete with causes effect documentation?

Bearing in mind that it's an ongoing investigation:

"The excessive level of Kathon in the aircraft’s fuel system is suspected to have caused the subsequent problems with the aircraft’s engines, including those experienced during the incident flight. The AAIB is also aware of other events where engine performance was affected by over-dosing of fuel with biocide. Visual inspection confirmed the presence of abnormal deposits within both engines downstream of the fuel spray nozzles. The influence of the over-dosed fuel on the engines’ HMUs and other fuel system components is subject to the ongoing AAIB investigation."

https://assets.publishing.service.gov.uk/media/5e9d5b4cd3bf7f0316b6a63a/AAIB_Special_Bulletin_S1-2020_G-POWN.pdf

[2Planks]

The reverend. I initially thought the same about the stall thing, but the interim report does state an engine stall warning was displayed. A new one on my, any 'Bus driver out there that could elaborate please?

[bvcu]

interesting. so now no approved treatment for fuel tanks in EASA countries. So is anything airworthy. Also note only one mention of a tech log entry ?

[tdracer]

The reverend. I initially thought the same about the stall thing, but the interim report does state an engine stall warning was displayed. A new one on my, any 'Bus driver out there that could elaborate please?
Not unique to Airbus - the newer Boeing designs will pop an EICAS message for an engine stall if it's unrecoverable or repetitive stalls - driven by logic in the FADEC.

Ivor, you just embarrassed yourself. Lomapaseo is far from a spectator - I suspect he's forgotten more about big turbofan engines than you'll ever know. At the risk of putting words in loma's mouth, like me, he's rather surprised that excessive much additive in the fuel could cause an engine malfunction/stall so quickly (long term effects - as residue builds up the fuel metering unit - is different). So we're hoping that the investigation would include testing with high levels of the anti-fungal additive - rig testing and full scale engine tests - to determine the exact effects and if the additive was in fact the root cause.

[charlies angel]

2planks and the reverend

Google ECAM Warnings for Airbus

Basically EVERYTHING is monitored by FADEC/SDAC ( Google is your friend 😃 )

The lower central tv screen will show a warning and identify Eng 1 2 3 or 4 as in a stalled/reversed airflow condition and this is a pilot memory item to clear the stall in the engine ( thrust levers to idle/ as appropriate )

It is possible to aerodynamically stall a modern Airbus but that is not what happened here and would require a PowerPoint Presentation to explain🤓🤓

So basically engine airflow was disrupted and this can cause airflow reversal which causes the flame. Imagine your Lamborghini Aventador spitting flames out of its exhaust 🤣🤣🤣

[Phil Kemp]

FAA SAIB issued on the subject. https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSAIB.nsf/dc7bd4f27e5f107486257221005f069d/05f721d6c7272c0986258536005bbe41/$FILE/NE-20-04_Corrected.pdf

[tdracer]

FAA SAIB issued on the subject. https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSAIB.nsf/dc7bd4f27e5f107486257221005f069d/05f721d6c7272c0986258536005bbe41/$FILE/NE-20-04_Corrected.pdf

Wow!!!
As a result, DuPont, the manufacturer and distributor of Kathon FP1.5, has recommended discontinuing the use of Kathon FP1.5 for aviation-related products. General Electric is also taking measures to remove Kathon FP1.5 from the approved fuels additives across all their engine products while additional testing is being conducted.
Maybe it's not the dose, perhaps it's the medicine itself?

[marvo999]

Looks like the MRO B1 put 60 kilos of Kathon in the aircraft instead of less than 2 kilos...........................

[ivor toolbox]

Ivor, you just embarrassed yourself. Lomapaseo is far from a spectator - I suspect he's forgotten more about big turbofan engines than you'll ever know. At the risk of putting words in loma's mouth, like me, he's rather surprised that excessive much additive in the fuel could cause an engine malfunction/stall so quickly (long term effects - as residue builds up the fuel metering unit - is different). So we're hoping that the investigation would include testing with high levels of the anti-fungal additive - rig testing and full scale engine tests - to determine the exact effects and if the additive was in fact the root cause.

Possibly, but no more than he did with his comment.
APPL jelly has also caused damage in the past too.

Ttfn

[Out Of Trim]

It was two different guys from two different maintenance organisations involved in this.
I'm surprised that a B1 Engineer wouldn't know what ppm meant, but it's really scary that the engineer at LGW was unable to use Airnav, pretty much everyone I know and have worked with can happily switch between Airnav and AirnavX. (personally I'm not a fan of AirnavX).
It's quite easy to screw up the effectivity in the A330 & A340 manuals in Airnav but this is due to the different weight variants, the A320 should be fairly straightforward so I've no idea how he ended up using a manual for a NEO.

Well, according to the AAIB Preliminary report; the LGW engineer did not even have access to the newer AirnavX.
Perhaps Airbus should only have the latest version available for use!

[Salusa]

So what "comedian" of an engineer did it then? Which company and who/where was the supervisor? Talk about basic error! Should not be working on aircraft, take their licence away, if they had one!

A reactive and unhelpful post. Now whilst the engineer may have been at fault I'm sure they did not go out of the way to make an error, no matter how serious.

Now whilst I agree that maybe the engineer did not have sufficient, knowledge and training to prevent this incident what was the root cause?

It's my opinion and only mine that gaining a B1 EASA licence is really just an matter of jumping through the right hoops and paying your money. The NCAA's within EASA are not to the same standard as each other with regards to acceptance, training and experience for engineer licencing.

The individual(s) obviously have to take some responsibility for thier actions or lack of but demanding an instant lynching is at best unhelpful.

[esscee]

The problem more and more nowadays is of licences being issued without sufficient experience in some NAA's, but proves the removal of a technical oral exam before licence issue was a great mistake when JAA then EASA took over from Section L.
Engineers who do not understand simple matters of how to use an AMM or what ppm is then should not be allowed anywhere near an aircraft. Days have gone when there were plenty of engineers around in hangars or on the Line, Operators have cut numbers to cut costs. However that is no excuse for not understanding how to carry out a basic task IAW AMM!

[bvcu]

The problem more and more nowadays is of licences being issued without sufficient experience in some NAA's, but proves the removal of a technical oral exam before licence issue was a great mistake when JAA then EASA took over from Section L.
Engineers who do not understand simple matters of how to use an AMM or what ppm is then should not be allowed anywhere near an aircraft. Days have gone when there were plenty of engineers around in hangars or on the Line, Operators have cut numbers to cut costs. However that is no excuse for not understanding how to carry out a basic task IAW AMM!
fully agree, also no mention of the MRO 145 organisation or the AMM having a procedure in place to carry out this procedure? Quality depts and EASA audits not doing their jobs. Despite all the engine start issues that preceded this there is no mention of a tech log entry. As these operators generally rely on a crew pre-flight and only log defects at end of days flying to save paying for engineering!

[TelsBoy]

There's some pretty unhelpful posts here. What good does public lynching do?

There are many worrying questions that result from this incident however. Mx staff not understanding procedures and terminology, no monitoring/check of work done, competency questions, haste in getting the job done without checking if its correct first, flight crews not logging previous issues and hence lack of investigation/follow-up... yes the engineer is responsible but the wider procedural, competency and quality procedures raise many more worrying questions and there are clearly gaping holes here.

Thankfully a good ending this time but it could easily have been very different. I hope lessons are not just learned but acted upon to stop this happening again.

[2Planks]

Charlie's Angel, thanks. Google often helps but often in these cases it descends into a labyrinth of acronym soup. From my mil career I was fully aware of flameout and surge, but only aerodynamic stall, which is why I asked.

[STN Ramp Rat]

Despite all the engine start issues that preceded this there is no mention of a tech log entry. !

BVCU I am not a pilot or engineer but I have to call you out on this, either you have not read the report or you have chosen to ignore the report to make a point.

Flight 1 ~ Stansted to Gatwick, Engine number 1 required more than one attempt to start, there is no mention in the report about a tech long entry.

Flight 2 ~ Gatwick to Krakow ~ the report says there were no issues and therefore no requirement for a tech log entry

Flight 3 ~ Krakow to Gatwick, ~ Page 3 of the report line 3 states the commander recorded the defect in the tech log and paragraph 2 line 4 that the engineer signed the certificate of release to service.

Flight 4 ~ Gatwick to Stansted ~ there is no mention of a tech log entry and the report does not cover the actions after landing but I would think the call to the AAIB would have been a reasonable substitute for a tech log entry in any case.

[bvcu]

read the report but only the LGW bit was highlighted , no mention of any AMM procedure carried out for the other start faults? Have heard through the grapevine that the LGW guy is being hung out to dry allegedly.

[India Four Two]

I've always thought that specifying quantities in terms of ppm is potentially confusing. Percentage is much more easily understood or for very small percentages like this case, specifying litres per 1000 litres might be better.

[DaveReidUK]

Percentage is much more easily understood or for very small percentages like this case, specifying litres per 1000 litres might be better.

Or, millilitres per litre - which comes to the same thing, but may be a bit more intuitive. Those are the units quoted in the FAA bulletin.

[WHBM]

There are many worrying questions that result from this incident however. Mx staff not understanding procedures and terminology, no monitoring/check of work done, competency questions, haste in getting the job done without checking if its correct first, flight crews not logging previous issues and hence lack of investigation/follow-up... yes the engineer is responsible but the wider procedural, competency and quality procedures raise many more worrying questions and there are clearly gaping holes here.
We can also start with selection of maintenance contractors nowadays, whether line or overhaul, with the prime consideration being who is bottom bidder.

[Big Pistons Forever]

Maintenance choices: Good, Fast, Cheap.

You only get to pick one and the airline execs always seem to pick cheap, while pretending the other 2 will magically also happen....

[Kit Sanbumps KG]

Maintenance choices: Good, Fast, Cheap.

You only get to pick one and the airline execs always seem to pick cheap, while pretending the other 2 will magically also happen....

There is more than a little truth in that. Perhaps ‘execs’, like the travelling public, believe that all the massively costly and inconvenient ‘regulation’ they are subjected to, should mean that the ‘cheap’ ones are also ‘good’ enough.

Having seen how profoundly some maintainers have sunk, and the deep and broad coping strategies applied by some flight ops departments, including check flights conducted completely outside the applicable regulations to cover up errors, I can only conclude that the necessary wake-up call will be truly shocking. With luck, the death toll will be minimal.

[TelsBoy]

We can also start with selection of maintenance contractors nowadays, whether line or overhaul, with the prime consideration being who is bottom bidder.

Pay peanuts, get monkeys. Seeing it across all areas of the industry. Costs/expenditure cut to the bone. Exceptional demands on service yet conversely the incessant demand for reduced cost; both cannot happen, one happens at the expense of the other. Meanwhile, shareholder dividends grow and grow. All great until the inevitable smoking hole occurs with hundreds of perished souls. Things no doubt going to get even worse considering the state the industry is in right now - if there is an industry left, that is.

[Fursty Ferret]

Maintenance choices: Good, Fast, Cheap.

You only get to pick one and the airline execs always seem to pick cheap, while pretending the other 2 will magically also happen....

I'm not convinced this necessarily applies here. Ratio calculations are notoriously easy to get wrong. Even the very best people make simple mistakes when dealing with parts per million (because it adds an extra step to a calculation) and this is likely exacerbated when working at night, tired, and under time pressure. There are some simple and obvious steps that can be taken to prevent this happening again:

1. Provide a worked example of the calculation in the maintenance manual.
2. Provide an electronic calculation in the maintenance manual (input contamination, biocide, fuel quantity and it spits out the required dose).
3. Supply the biocide in smaller containers. Even the person who's absolutely confident of their calculation will think again if they realise they have to log, open and pour (for example) 60 bottles of the stuff into the aircraft.

[TelsBoy]

I'm not convinced this necessarily applies here. Ratio calculations are notoriously easy to get wrong. Even the very best people make simple mistakes when dealing with parts per million (because it adds an extra step to a calculation) and this is likely exacerbated when working at night, tired, and under time pressure. There are some simple and obvious steps that can be taken to prevent this happening again:

1. Provide a worked example of the calculation in the maintenance manual.
2. Provide an electronic calculation in the maintenance manual (input contamination, biocide, fuel quantity and it spits out the required dose).
3. Supply the biocide in smaller containers. Even the person who's absolutely confident of their calculation will think again if they realise they have to log, open and pour (for example) 60 bottles of the stuff into the aircraft.

Surely any ongoing competency assessment/training would account for this? As I previously said, many uncomfortable questions opening a can of worms, all too easy to blame the individual and not the organisational and procedural failings.

[WHBM]

I do agree that stipulating a heavy engineering operational instruction in ppm is almost deliberately making things difficult. But we can extend our discussion of "cheap" to the maintenance manual production, where once upon a time a professional in house technical documentation author would never have simplistically written it like that. Instead outsource the production, again to the low bidder, and they will just whack in the product manufacturer's spec sheet without consideration.

Steve Jobs, when he led Apple Computers, had a "thing" about simple and straightforward. The first demonstration of any major new product was to him. If there even one ambiguous or surplus operation (in his mind) he used to blow up the team members there and then, who thus knew to take infinite care to get it all the best that could be done. This additive instruction would absolutely fail the Jobs test - complex calculation not explained, technical abbreviation not explained, abbreviation not commonly used elsewhere (otherwise the operative would be familiar with it), abbreviation of something not in the operative's own language, etc.

[TelsBoy]

I do agree that stipulating a heavy engineering operational instruction in ppm is almost deliberately making things difficult. But we can extend our discussion of "cheap" to the maintenance manual production, where once upon a time a professional in house technical documentation author would never have simplistically written it like that. Instead outsource the production, again to the low bidder, and they will just whack in the product manufacturer's spec sheet without consideration.

I worked in a previous life for an avionics manufacturer that used to have professional spec writers, employed solely to write test procedures, manuals etc. In other words, they'd take what the boffins and bods would give them and translate it into something legible for those of us of a more... average... intelligence. That's long gone and when I was there the production engineers themselves had to write the specs, procedures and manuals. I think its the same across all industries.

[Uplinker]

Without wanting to blame the hapless engineer, Googling something and then using a random calculator found somewhere on the internet, but without fully understanding the terminology...........Why did he not have access to a proper procedure and a proper, validated calculator?

Engine critical procedures, such as opening the cowl flap locks, the engine oil caps etc., have mandated dual inspections. Why not for fuel additives? Fuel is pretty critical !

Engineers attending aircraft I have flown, have print-outs of the procedures, and often phone another authority if they are not familiar with a particular procedure, to check. And that is fine and sensible.

Why this guy did not phone his boss or another engineer to check his figures is beyond me.

[Sallyann1234]

Didn't want to admit/display his ignorance ?

[esscee]

But who was the supervisor that oversigned/stamped the task? If he did the task and able to countersign/stamp it then that is even worse, in that someone with that authority did not know/understand the task details and what he was meant to do! For heaven's sake who was the MRO management/QA people allowing such a person to be working on aircraft? Absolutely frightening for the paying customers and equally for the crew flying the aircraft!

[TelsBoy]

But who was the supervisor that oversigned/stamped the task? If he did the task and able to countersign/stamp it then that is even worse, in that someone with that authority did not know/understand the task details and what he was meant to do! For heaven's sake who was the MRO management/QA people allowing such a person to be working on aircraft? Absolutely frightening for the paying customers and equally for the crew flying the aircraft!

One of my key points. Who's checking the work, ongoing staff competency/recency, training, procedures etc. If the engineer didn't feel they could ask a question/confirm something, why? Wasn't there a supervisor or colleague available, if not why not, if so then why couldn't they ask them? Was the engineer pressured into finishing a job at all costs rather than step back and leave it if unsure? Is there an unsafe culture where staff cannot ask questions freely without reproach or judgment? Are unsafe or incorrect practices challenged? Sounds like some simply want to lay the blame on the engineer rather than deal with the much wider and more pressing issues.

[lomapaseo]

In order to keep a balance in the discussion we should also look beyond the blame of a person and also look at safety nets beyond the initial mistake. Perfection is not possible, we also depend on mitigation or shielding (redundancy, detection etc.)

[pilotmike]

Even the very best people make simple mistakes when dealing with parts per million (because it adds an extra step to a calculation)
Really? How does 'per million' (divide by 1e6) "add an extra step to a calculation", where 'per cent' (divide by 1e2) does not?

Indeed, in such a high dilution ratio as this (1: 0.0001, or 0.001% or 100PPM), it is arguable that PPM is the clearest way to express it, as it uses only whole numbers. Also, being a multiple of 1e3 (1,000), it works very well with standard x1,000 multiples {eg. (k)g, (m)l etc.}, where % is x100, which prevents such easy multiples and the relatively simple use of k(ilo) m(illi) prefixes.

Both PPM and % are valid ways for engineers / scientists to express dilution ratios. Neither should be more or less likely to be prone to error, and certainly not by "add[ing] an extra step to a calculation", as you claim. Competent engineers should be expected to be able to work accurately with either.

[cashash]

But who was the supervisor that oversigned/stamped the task? If he did the task and able to countersign/stamp it then that is even worse, in that someone with that authority did not know/understand the task details and what he was meant to do! For heaven's sake who was the MRO management/QA people allowing such a person to be working on aircraft? Absolutely frightening for the paying customers and equally for the crew flying the aircraft!

I would assume that the certified the task himself if he was a Licensed Engineer. With regards to the screw up over the calculation, as the MRO seems to be based in Cyprus perhaps English was not his first language and the instructions in the AMM were not totally understood - it is a situation that I have seen numerous times overseas especially with Airbus manuals that seems to be written by a committee when compared to those from Boeing.

[Webby737]

I would assume that the certified the task himself if he was a Licensed Engineer. With regards to the screw up over the calculation, as the MRO seems to be based in Cyprus perhaps English was not his first language and the instructions in the AMM were not totally understood - it is a situation that I have seen numerous times overseas especially with Airbus manuals that seems to be written by a committee when compared to those from Boeing.

I agree with this, even for someone like me whose first language is English the Airbus manuals can sometimes be hard work.

One small example of this, if you look in one of the uncustomised manuals (The SRM for example) Airbus will list each and every MSN, one list might be the A319, another the A320 etc, etc. Why couldn't they just state A319, A320 or Effectivity ALL ?
The effectivity can be filtered in Airnav or AirnavX but it doesn't always work.

Boeing make your life easier with "Effectivity ALL" or B737-700 etc.

[Chu Chu]

Since the concentration was specified in PPM by volume, but both the fuel and the product are normally measured in KG (and have different densities), there were actually 4 calculations required:

1. Convert the 6200 KG of fuel to 7678 L.
2. Convert 100 PPM to .0001.
3. Multiply 7678 L of fuel by 0001 to get .7278 L of product.
4. Convert .7678 L of product to .799 KG.

And that's after looking up the specific gravities of both the fuel and the product.

If the procedure had said that 1 KG of product treated 7760 KG of fuel, the calculation would have looked like this:

1. 6200 KG divided by 7760 equals 0.799 KG.

[Ex Cargo Clown]

Really? How does 'per million' (divide by 1e6) "add an extra step to a calculation", where 'per cent' (divide by 1e2) does not?

Indeed, in such a high dilution ratio as this (1: 0.0001, or 0.001% or 100PPM), it is arguable that PPM is the clearest way to express it, as it uses only whole numbers. Also, being a multiple of 1e3 (1,000), it works very well with standard x1,000 multiples {eg. (k)g, (m)l etc.}, where % is x100, which prevents such easy multiples and the relatively simple use of k(ilo) m(illi) prefixes.

Both PPM and % are valid ways for engineers / scientists to express dilution ratios. Neither should be more or less likely to be prone to error, and certainly not by "add[ing] an extra step to a calculation", as you claim. Competent engineers should be expected to be able to work accurately with either.

Scientists don't really use PPM because it's far too ambiguous. We generally use molar concentrations for liquids. Makes it far easier.

[pilotmike]

Scientists don't really use PPM because it's far too ambiguous. We generally use molar concentrations for liquids. Makes it far easier.
Do you really believe this engineer, who royally screwed up the mixing, using 40x the correct amount, would have coped with the molecular concentration calculations?

Having demonstrated themseIf to be utterly defeated by 100ppm, it is unreasonable to believe they'd have aced molecular concentrations, never mind finding it "far easier" as you claim.

As the manufacturer knows the density of their own product, and using as standard fuel density, Chu Chu's suggestion of the manufacturer specifying 1kg of product to 7,760kg of fuel is easily the best suggestion, as that is the very simplest calculation by a long way.

Inside every vexing problem is a very simple solution (ha!) struggling to be seen!

[IRRenewal]

3. Multiply 7678 L of fuel by 0001 to get .7278 L of product.


If ever we needed proof how easily these things can go wrong.

[Pugilistic Animus]

Er, the AAIB is UK equivalent of US NTSB,
the answer is yes to both your points, you might want to go back to the spotters balcony now and leave further discussions to grown ups

That's the funniest statement I've heard here in a long time...to save yourself further embarrassment try reading a few older posts of someone before deriding them. I learn a lot from him reading his post

I'm just saying

[old,not bold]

I'm struggling to understand why the manufacturer suspended the use of Kathlon, especially when doing that leaves EU operators with no approved biocide treatment.

It wasn't the product that caused the problem, it was gross misuse of it.

Failing a technical reason, perhaps the manufacturer's insurer is behind it?

On another topic, I hope that the "on-going AAIB investigation" includes a systematic MEDA (or equivalent) analysis of the Human Factors involved, for the industry's benefit as well as the AMO concerned.

[EDLB]

Easiest would be if beside the 1kg treats 7.760kg of Jet fuel, a table for typical even masses of fuel is given. Like 129g for 1000kg 1.288kg for 10.000kg etc. At least that allows to check, that your calculated number is in the ballpark. On that product I doubt, that +/- 20% error would matter much, but you should not get it wrong by orders of magnitude.

As pilot you often use rule of thumb calculations for checking if the number given make any sense.

[pilotmike]

Easiest would be if beside the 1kg treats 7.760kg of Jet fuel, a table for typical even masses of fuel is given.... you should not get it wrong by orders of magnitude.
1kg doesn't treat 7.760kg of fuel.

As pilot you often use rule of thumb calculations for checking if the number given make any sense.
"You should NOT get it wrong by orders of magnitude." - in your very own words!

You should be "checking if the number given make any sense" - in your very own words!

[slfie]

1kg does NOT treat 7.760kg of Jet fuel!!!
...


That's possibly because of the continental way of using a decimal point in place of a comma, i.e. UK (and US) would write 7,760Kg but some european countries would write it as 7.760Kg (so there's a potential error of 3 orders of magnitude there). Certainly in the post it's confusing to my (UK) eyes, saying 1000Kg then 10.000Kg for 10 times as much.

Irrespective of the original dosing, the more surprising (and dangerous) thing is it didn't get picked up before it caused loss of thrust at take-off. Mistakes happen, but it does seem this one should have been caught long before it got as far as it did (the potential being there for a considerably worse outcome).

[Momoe]

Before anyone else criticises ground maintenance and throws in the "Pay peanuts, get monkeys adage", how many folk at the pointy end have royally screwed weight calculations and had some interesting flex take offs, or failed to configure correctly for take-off.

One common denominator here and that is we're all human.

[Salusa]

I agree with this, even for someone like me whose first language is English the Airbus manuals can sometimes be hard work.

One small example of this, if you look in one of the uncustomised manuals (The SRM for example) Airbus will list each and every MSN, one list might be the A319, another the A320 etc, etc. Why couldn't they just state A319, A320 or Effectivity ALL ?
The effectivity can be filtered in Airnav or AirnavX but it doesn't always work.

Boeing make your life easier with "Effectivity ALL" or B737-700 etc.
Agreed 100%

I'm B1. 3 (Turbine Helicopters) and the difference between Airbus/Leonardo vs Bell/Sikorsky is a world apart.

Euro manuals are dumbed down to the point of the lowest common denominator, but somehow manage to complicate it even further!

​​No schematics or system explanation in Euro. Just an idiots guide which you are expected to follow verbatim.

Literally two pages of instructions to remove a Filter with illogical cross references and tasks, rather than "remove the filter".

Now whilst not relevant to this particular incident its a pointer of what is wrong these days.

The qualifications required to obtain a LAME has been dumbed down and now we are seeing the results. EASA standards are not universal across EASA.



​​​​​



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​​

[Big Pistons Forever]

Nobody has talked about the role of the regulator here. The engineer held a license issued by an aviation authority with skills and knowledge requirements defined by them, arguably significantly dumbed down from what used to be required. The manual he was using and which you could make an argument was not fit for purpose, was approved by the authority.

industry on both sides of the Atlantic have actively pushed to marginalize and neuter regulators. This works great and saves manufacturers and air operators tons of money until the airliner dives itself into the ground or the whole rotor comes off the transport category helicopter at 2000 ft AGL.......

[Kit Sanbumps KG]

Nobody has talked about the role of the regulator here

It was a couple of days ago...

Perhaps ‘execs’, like the travelling public, believe that all the massively costly and inconvenient ‘regulation’ they are subjected to, should mean that the ‘cheap’ ones are also ‘good’ enough.

[winglit]

I agree. The amount of fuel in the aircraft is measured in weight, but the amount of additive to be added is in volume.

The AMM writers were a bit sloppy with that procedure. I haven't checked the Airnav glossary recently, but I wonder if PPM is actually there. And in any case, how hard would it have been to clarify and write Parts Per Million?

Airbus manuals are usually full of charts and tables. Why didn't they add one detailing the amount of additive according to fuel tanks contents.

[WHBM]

I agree with this, even for someone like me whose first language is English the Airbus manuals can sometimes be hard work.
Bear in mind that at Airbus the Technical Author is unlikely to have English as their first language, as well.

[esscee]

So who proves reads the manuals after they are initially written, anyone close to hand, office cleaner? For heaven's sake, to say that a Tech author is unlikely to have English as their first language is ridiculous, employ one who does have English as their first language. Simples!

[Webby737]

Bear in mind that at Airbus the Technical Author is unlikely to have English as their first language, as well.
Quite true, French is my second language and often it helps when trying to decipher what is required by the AIB manuals.
I'll also add that many of the employees, including I suspect the ones that write the manuals have never worked in aircraft maintenance. A couple of years ago during an Airbus audit I was asked a question, my reply was "we use the SRM"
The next question was "what's an SRM?"

[Webby737]

So who proves reads the manuals after they are initially written, anyone close to hand, office cleaner? For heaven's sake, to say that a Tech author is unlikely to have English as their first language is ridiculous, employ one who does have English as their first language. Simples!

I think they are proof read by someone who might have a good grasp of English but not necessarily technical English.
Still, at least they are better than the Sukhoi manuals, I think they used Google Translate on those !

[Webby737]

The AMM writers were a bit sloppy with that procedure. I haven't checked the Airnav glossary recently, but I wonder if PPM is actually there. And in any case, how hard would it have been to clarify and write Parts Per Million?

Airbus manuals are usually full of charts and tables. Why didn't they add one detailing the amount of additive according to fuel tanks contents.

It was noted somewhere in the report that PPM was not in the Airnav glossary.

[pilotmike]

So who proves reads the manuals after they are initially written, anyone close to hand, office cleaner?!
Who proofread that?

[cashash]

It was noted somewhere in the report that PPM was not in the Airnav glossary.

It is in my pdf copy of the MM. I dont now have access to Airnav so cant check that.

[lomapaseo]

Airbus is kind of a large company with a very broad employee base in their engineering departments. I wouldn't even consider a shortfall in writing skills towards the benefit of their customer base. What to communicate, how and where.may be argued here.

[woptb]

Before anyone else criticises ground maintenance and throws in the "Pay peanuts, get monkeys adage", how many folk at the pointy end have royally screwed weight calculations and had some interesting flex take offs, or failed to configure correctly for take-off.

One common denominator here and that is we're all human.

A lot of perfect humans on here!
Passing comment is fine,but passing judgement, without being in possession of all the facts is rather dumb!

Everyone has screwed up royally in the work place,if you never have,it’s just a matter of time! To hear some of the posters pontificating on this is rather irksome.When you screwed up or when you screw up,it doesn’t necessarily make you an idiot,just human! Next you’ll all be telling me you’ve always follow procedures............

[Webby737]

It is in my pdf copy of the MM. I dont now have access to Airnav so cant check that.
I can't check either, I don't have access to Airnav from home but it looks like it may have been revised, here's an extract from page 10 of the report."In addition, the AMM task instructions used the term ‘ppm’ for which there was no definition within the AMM glossary, and no additional guidance was provided of how to perform the biocide fuel dosing calculation."

[Webby737]

A lot of perfect humans on here!
Passing comment is fine,but passing judgement, without being in possession of all the facts is rather dumb!

Everyone has screwed up royally in the work place,if you never have,it’s just a matter of time! To hear some of the posters pontificating on this is rather irksome.When you screwed up or when you screw up,it doesn’t necessarily make you an idiot,just human! Next you’ll all be telling me you’ve always follow procedures............

Quite true,
The only way to never f*ck up is to do nothing !

[Winemaker]

Or, millilitres per litre - which comes to the same thing, but may be a bit more intuitive. Those are the units quoted in the FAA bulletin.

Yes, the way I calculate additives in the winery is 1 ppm = 1 mg/L. This makes it very easy to do rough calculations on the fly and is a good check before dumping stuff in.

[FlightDetent]

While I can attest that operating a contemporary jet is not an exact science, certainly there is hope that the engineering would be. PPM stands for 1 x 10^(-6), no units given - it's a simple multiplier. 1 ppm = 1 mg/L That does not taste right. Perhaps mg/kg or ml/m^3, anyone?

A case of a point for the voices saying ppm is hard to grasp on the line:

density of jet fuel 0,785
density of Kathon 1,05

Which are the actual correct units to be used for diluting the additive according to AMM and the spec-sheet? Molecular, mass, or volume?

[DaveReidUK]

Perhaps mg/kg or ml/m^3, anyone?

Are you suggesting that fuelling in cubic metres could catch on ?

[FlightDetent]

Are you suggesting that fuelling in cubic metres could catch on ? Ok, call it kilo-liters if m3 sounds overly continental for the islands. 8-)

Two morals of the story:

mg (mass) / l (volume) is perhaps fine for a winery (density 1,005 - marginal error). For jet A1 (0,785) and Kathon (1,05) mixing volumetric and mass units gives you a nice compound error 26% even if you get the multipliers right and/or avoid the trap of mis-reading a comma in-lieu of a dot for the decimal divider.
If there's ml one side, for PPM to work instinctively i.e. avoiding the order-of-magnitude error, you need to have kilo-liters (m^3) on the other. Well pointed that's not the case, hence the argument of PPM being a stupid choice of a field-deployable unit.


Question stands. Which units - weight or volume - are used in the original Kathon recipe of the AMM?

[cashash]

Question stands. Which units - weight or volume - are used in the original Kathon recipe of the AMM?


The answer is 'volume' - I did notice though that if you are using Biobor then the units are 'weight'

https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/732x407/screenshot_from_2020_04_27_15_00_12_23626760621163d8479b24ac 5528eb53c7fe880e.png

[cashash]

As an aside if you use a metered injection rig to carry out the addition of the Kathon, the AMM provides a handy calculation chart to get the correct amount.



https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/741x837/screenshot_from_2020_04_27_15_02_49_aacbcb5073740b04565a8995 24b74f0e6a030d52.png

[FlightDetent]

'volume' - I did notice though that if you are using Biobor then the units are 'weight Priceless.

Thanks. The page from your second post instructs to use KG reading in order to add biocide PPMs by volume. Right, no further questions.

[Winemaker]

While I can attest that operating a contemporary jet is not an exact science, certainly there is hope that the engineering would be. PPM stands for 1 x 10^(-6), no units given - it's a simple multiplier. That does not taste right. Perhaps mg/kg or ml/m^3, anyone?

When adding weight per volume, which is how this additive is used, it's exactly right. For example, if the rate of addition (I'm just making up numbers here} is 100 ppm (100 mg/L) and the volume of fuel is 7000L we would need to add (100 mg/L)(7000 L)/1000 mg/g = 700 g or .7 kg. Pretty simple.

[FlightDetent]

Not sure altogether if we are speaking about the wine or biocide. Wine has a density of 1,005 so mixing weight (mg) with volume (l) is a foul play that gives acceptable results.

Hopefully, we agree that ppm is a unit-less multiplier. Per-cent is 1/100, per-million is 1/10^6.

The AMM above says PPM (by volume) thus I would expect a proper calculation in volume : volume units. To adress the density issue (fuel tank gauges in KG, dosage in l or ml - I only assume here), the calculation guidelines in a pilot-proof world would need to take this form:

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/643x366/ppm_2d53bc7ec9d3b6d8165262e1f5779ecb4e1bff5e.png

Using your numbers of 7000 L fuel to achieve 100 ppm by volume, 0.7 L of agent needs to be added. And that is 735 g of the matter. If you say the recipe on the can does actually instruct to mix mili- or kilo- grammes on one side and mili- or full liters on the other (either way) - I'll take your word for it. But calling that ppm is gobbledygook.

One more thing I inserted into that pilot-proof example. Realistic values. Which provides the reader with an outlook on what his result should look like. Compare that with the AMM original text suggesting adding 10000 kg / lbs ontop 10000 kg/lbs of fuel already there. Pardon me? There is no tank on the machine that'd hold 10.000 kg of fuel nor 20000 lbs by a wide margin!

Massive case study on how many things can be unhelpful in a technical writing. Unhelpful actually does mean incorrect and wrong. Human Factors - biting the bottoms since well before the Wright brothers.

With Occam's razor, my gut feeling is that the decimal denominator "," "." actually got mixed (same happened in posts #56 and #57 here) and something got multiplied by 1000 rather than divided. Who knows, happy everyone survived to tell the tale.

[Winemaker]

I agree with you. My confusion, as I am not in aviation, was with the (for obvious reasons) aircraft usage of weight of fuel versus volume. I was calculating weight/volume for the ppm addition as the amount was reported in kg.
Using your numbers of 7000 L fuel to achieve 100 ppm by volume....
I understand. Anyway, this stuff is so simple and it's so easy to generate a simple spreadsheet or graph to do it automatically........ Kg fuel in, addition rate calculated.

[Salusa]

Nobody has talked about the role of the regulator here. The engineer held a license issued by an aviation authority with skills and knowledge requirements defined by them, arguably significantly dumbed down from what used to be required. The manual he was using and which you could make an argument was not fit for purpose, was approved by the authority.

industry on both sides of the Atlantic have actively pushed to marginalize and neuter regulators. This works great and saves manufacturers and air operators tons of money until the airliner dives itself into the ground or the whole rotor comes off the transport category helicopter at 2000 ft AGL.......
I wish there was a "Like" button sometimes.

Your post summarises it.

[DaveReidUK]

The AMM above says PPM (by volume) thus I would expect a proper calculation in volume : volume units. To address the density issue (fuel tank gauges in KG, dosage in l or ml - I only assume here), the calculation guidelines in a pilot-proof world would need to take this form

The fly in the ointment is that, as the report makes clear, Kathon FP1.5 is packaged and supplied by weight, not volume:

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/373x417/kathon_db395e9067e22d7b215d3fbb429675a3803083a2.jpg

[stormin norman]

Make the adding of any additives to fuel a duplicate inspection item . Surely they cant have 2 people working for the same organization capable of making such a monumental mistake ?

[FlightDetent]

The fly in the ointment is that, as the report makes clear, Kathon FP1.5 is packaged and supplied by weight, not volume: That's logistics, how you administer it is what matters. Pouring it out of the canister into a measuring cup, what are the gauges on it? A volume-labelled cup is easy to find, calibrate and fits the calculation of PPM (by volume) easier. A mass-calibrated cup is imaginable, as well as a dosing device that weights the substrate.

Neither is of which is my expertise and admittedly in line with your remark the AAIB Bulletin (thanks for making me actually read it) has an extra step. To convert the volumetric dose figured through the ppm (by volume) requirement into mass for Kathon.
https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/614x168/aaib_b6684f6ab0181a820749ec89b9f79b90079283ff.png
My aim was only to illustrate how much different the form of the instructions for mixing needs to be compared to the unusable excerpt we've seen from of the AMM. Well, if that were meant for pilots to read and apply. ;)

Given the past performance of the authors, I will be excited to read the full report later. Neither my equation nor the calculation in the bulletin addresses the practicality for ramp use. In that respect both are equivalently not too good, requiring several steps to derive the input values first. Let's see how many loose ends they will find.

[Fursty Ferret]

Competent engineers should be expected to be able to work accurately with either.

You're absolutely right, it's not a complicated calculation. But it *is* easy to get wrong with very little indication that you've made a mistake.

Someone who's sat comfortably at a desk, during the day, with no time pressure is able to complete this calculation repeatedly and without difficulty. At 3am, cold, hungry and covered with JET A1 is a totally different proposition.

At this point there's not necessarily a huge point in making someone else repeat the calculation independently, because two people can get it wrong. Putting a big label on the can that says "this treats approximately 50 tonnes of fuel" is a bit of mental maffs that anyone can do.

[Uplinker]

Putting a big label on the can that says "this treats approximately 50 tonnes of fuel" is a bit of mental maffs that anyone can do.

There's the answer, right there to this "Swiss cheese line-up". :ok:

The only thing I would add is, have a clear pictogram of that information on the container as well as text* The poor sod covered with JetA1 at 03:00 might not speak or read English very well..............

*Or even better maybe: a series of marks down the container side with a clear band to see the liquid level through, and the amount of JetA1 that fluid up to each mark would treat.

[Terry McCassey]

Make the adding of any additives to fuel a duplicate inspection item . Surely they cant have 2 people working for the same organization capable of making such a monumental mistake ?

You make good point. You are, after all, working on both engines at the same time on an ETOPS capable aircraft.

[bvcu]

Lot of current production aircraft have no overwing refuel capability. Therefore an alternative procedure to put baobar in is required. As its not generally specified in the AMM of a lot of types it should be a company procedure as per their 145 approval to specify what equipment and how . Probably in the to difficult pile for the auditors from all the different authorities that most MRO's hold approvals from as we're in an environment of approved companies now so not just an individual .

[cashash]

Lot of current production aircraft have no overwing refuel capability. Therefore an alternative procedure to put baobar in is required. As its not generally specified in the AMM of a lot of types it should be a company procedure as per their 145 approval to specify what equipment and how . Probably in the to difficult pile for the auditors from all the different authorities that most MRO's hold approvals from as we're in an environment of approved companies now so not just an individual .


The equipment to use to inject Biobor is specified in the MM

COM-1781 HAND CART STYLE ADDITIVE INJECTION SYSTEM (http://www.scanaerotech.com/shop/com-1781-hand-cart-2910p.html)

[DDDriver]

And the press interpreted "A "stall" message was displayed in the cockpit three times" to mean the second engine stalled. I'm assuming the stall warnings were due to low-airspeed and high AOA.

Surely “three times” must mean that engine #3 failed as well? :}

/tabloid mode

[keri]

Fursty Ferret;

As a former (miltary) engineer and latterly ICU Nurse Specialist, I can testify that proportional calculations can be problematic. Millilitres per litre and micrograms per kilo body weight etc can prove head wrecked when under stress. The PPM issue though is hard to credit......

[megan]

The data sheet,Aviation Fuels - Water and sludge should be removed from fuel tanks before application of the biocide.

100ppm v/v of KATHON™ FP 1.5 as supplied should be used to achieve microbial control, as described by EU BPD and US EPA regulations. To achieve this, the user should treat every 10,000 litres of aviation fuel with 1 litre of KATHON FP 1.5. The biocide should be added in such a manner so as to allow good mixing and distribution across the fuel. Ideally, this should be into a fuel supply line to ensure agitation. A contact time of up to 24 hours is recommended, depending on the severity of infection.I presume your fuel is dispensed in litres, so a simple calculation to make if abiding by the data sheet. Seems Airbus may have overthought the procedure.

http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_08d0/0901b803808d0ff2.pdf?filepath=microbial/pdfs/noreg/253-03153.pdf&fromPage=GetDoc

Looks like Kathon is being replaced with FuelClear AV15 - awaiting aviation approval. The company says "Kathon FP 1.5 Fuel Biocide is being discontinued for aviation applications with immediate effect". Result of this incident?

https://www.fuelcare.com/industries/aviation/fuelclear-av15.html

Am I missing something? The Airbus manual talks about mixing by volume then uses weights for the calculation. One doesn't equal the other, specific gravity of the product is 1.04.

[Fursty Ferret]

Don't forget the Airbus restrictions are based on the biocide causing problems with the aircraft, while the manufacturer's instructions have the goal of killing anything unwanted in the fuel. They might not be comparable.

[FlightDetent]

Am I missing something? The AMM is completely messed up. Even if you manage to follow that guidance, you'd reach an incorrect result.

Although for the accident in question mistakes had been made between the AMM and the bowser, an order of magnitude greater.