Thanks for the video & additional info! Your narration timing has become really confident and sharp compared to the early videos. You deserve a better mic and a bit more acoustic padding around it, though, there's a slight hard reverb probably due to your desk etc reflecting your voice.
I'm a chemist: I work with those type of calculations everyday. What troubles me is that the archaic unit of ppm was used. The units should be mg/kg, or mg/L, because the unit ppm does not take the density of liquid into account.
The procedure is to bring the concentration to "100 ppm by volume." The engineers misinterpreted this (from the incident report): "When asked what ‘by volume’ meant in the biocide procedure, Base Engineer 2 stated it meant that if one of the quantities was in kilos, you must calculate the other quantity in kilos." This would only account for a small error in dosage though, as kathon is only 30% denser than jet fuel. The bigger issue was the conversion to 0.01% and then using that as 0.01 instead of 0.0001.
PPM is not an archaic unit, in fact it is has no units. It is used when it does not matter whether the measurements are by weight or volume. Example: I have an epoxy adhesive whose Part A has the same volumetric parameters as Part B and I can choose to measure them in whatever unit happens to be convenient at the time. I agree that the unit is often used without specifying the units when the units DO make a difference, like in atmospheric pollution, though often they are for comparison with a reference limit so the unit doesn't matter, e.g. 6 ppm of xxxxx substance, limit is 20 ppm before a mask is legally required.
@@TemporalWolf Interesting. I would otherwise have assumed that weight would be the way to go at all times since volume would be affected by temperature. I wonder why the instructions say to use volume?
@@ToddGlasier We rely on our experience and our coworkers to get things done right. The maintenance manuals help with some of the details but most of it comes from actually doing it. Airline mechanics work on the same types of planes all the time so they get better at it. It's only when something is new and different that it's risky. But there are several checks and redundant systems in place to make air travel super safe.
Even when knowing what PPM stands for, the technicians still didn't have the information required, which should have been abundantly clear in the aircraft manuals.
@@sansationalguy9180 If two different technicians both decided to Google it instead of calling someone it's not illogical to assume that they've been instructed to do this by someone.
I taught math in the past, and I couldn't agree more. It's a more interesting problem than most book problems, and it's an excellent example of why it's good to know math in "the real world". It would also allow for talking about how to research things on the internet and check your work.
@@martinmckee5333 I get both amusement and exasperation from hearing my chemistry/astronomy/physical science students express horror and shock that they can't type my questions into Google and get the answer.
"What's 'PPM'?" "It's just like percent, but multiplied by 10,000." "Okay so I converted that to percent. Is it by mass or by volume?" "I don't know, consult the maintenance manual." "The maintenance manual doesn't say." "Google it." "Sure thing boss." *dumps 60kg of powder into fuel tank because too afraid to ask more questions and look stupid*
I suspect that the report focused too heavily on "didn't know what ppm means". You would be very hard put to find any engineer of any field that doesn't know what that means. Instead, I'm guessing what the engineers were saying is that they didn't really know what ppm meant _in context_. As you pointed out, the primary misstep was precipitated by them not knowing it meant "by volume" instead of "by weight". I would love to argue that the entire fault is on those who introduced the procedure into the workflow. But honestly, I have to say this is just one of those things that happens when you have so many disparate groups involved. From the creators of the mix who think in chemistry all the way through to engineers in the hanger who think in weight. PPM is well understood in every part of that. It just means something different in two of them.
Also i think that the repair manuals are at the main fault here, it should've gone over it or at least gave another source where they can go too, too find information on how to do the mixing.
Well no, because they had to google what the term meant. They honestly didn't know. Then they made several other errors after that, but really; they didn't know what it meant.
@@maria50337 I think the search might have been more like .........O.k. one hundred parts per million. I get it. Hey, wait this is ending up to be one hell of a lot of antibacterial. More than in one of the giant packages. Hmm, maybe I better make sure there isn't some other ppm thingie I don't know about. OK. There it is in black and white. Well, if they want a hundred parts per million then that is what I'm going to give them. Geez, now I have to order in some more antibacterial because now we have just used up most of our supply.....
mixing up volumetric ppm to gravimetric ppm would not cause a great mistake, the densities just do not differ by 30-ish times. Shouldn't cause a major problem. Not properly mixing the stuff is a big deal.
let alone the fact that the presenter made a mistake, probably the very mistake the engineers did, while google was right: 0.01% of 6200kg is 0.62kg (== 6200*0.01/100), NOT 62kg!!! (==6200*0.01)
7:27 - Assuming your reporting is correct, you’ve made the same mistake as the engineers. 0.01% (PERCENT, not a ratio) of 6200kg is 0.62kg, not 62kg. The roughly 30% difference in mass to volume is almost irrelevant if a mistake this big occurred.
The difference between ppm mass and ppm volume between jet fuel and a liquid additive is never ever going to be off by a factor of 100. Even if you're adding mercury to jet fuel (please don't) the difference between ppm mass and ppm volume would be a factor of 20 or so. But this additive is not mercury. My guess is that the liquid densities differ by a factor of 1.5 or less, and the mixup would have nearly no effect on engine performance. It's a pretty glaring mistake -- I wonder if it was made in the official report or just this narrator.
I was about to write the same... There is just no realistic way for a mass/volume relation to be different by factor 100. To get a factor 100, one needs some really exotic examples. Adding the same volume of mercury (13.5 kg/l) instead of liquid hydrogen (0.07 kg/l) to a fuel tank would give a factor of 200, but that's really stretching things... They should just write something like "add 100 grams of biocide for each 1000 liters of fuel". The fact that the biocide was packaged in 150 kg bags is also not helping. This makes the mistake totally understandable, about half a bag to treat one plane seems reasonable.
I currently work on these type of aircraft, specifically those with the LEAP-1A engines, and CFM-56; but I've also had years of experience on the other available engine types for this airframe. For anyone curious, the video features an A321ceo with V2500s, not the accident engine. We have our own manuals but also use AirNav as a supplement. You'd almost have to be completely unaware of the type of aircraft you're working on to confuse a CFM56 with a LEAP-1A and in my opinion that is a far, FAR bigger issue highlighting the inexperience of the technicians. These engines are quite different, even to an untrained eye. The instructions for task in question may not have been clear but it is the duty of the technician to seek out the appropriate documentation. If you don't know, and don't have an answer, then you need to find an answer. Google is never an acceptable technical reference. That is something we get taught in our basic training before we even get into the industry proper. Out in the field when we see a task that is unclear or poorly worded we're required, by law, to report it and have it corrected and clarified BEFORE attempting to perform the task. Also, for what its worth, I was taught what PPM meant and use those measurements regularly. It sounds to me like the technicians in question didn't really have the appropriate tooling, training, or experience. This, combined with operational pressure, set them up for failure from the beginning.
Surely the producers of the anti-bacterial mix could make things much clearer. "Use the xyz equipment attached to the abc hose and for every 100 litres of fuel add 10 litres of fluid". Pretty explicit and constant for any type of fuel. If the specific gravity and temperature of the fuel makes a difference then a small table showing the amount to add per 100 litres could be shown. I think the manufacturer should have taken responsibility for proper instrauction. I'm sure others will disagree. Love these videos. Keep going.
That’s true I’m not even an engineer or something I just enjoy flying and even I know that one is shorter more „square“ looking from the side while the other ones are longer tubes
I am an aircraft engineer and have found PPM quite common in the description of an additive, but usually it gives you another figure, such as ratio or volume unit. I'm still astounded that any engineer had not heard of PPM though, it's quite a basic engineering term, just not great for the end user.
Parts per million being sent to mechanical based people is 100% asking for disaster. Add to that a lack of semi soluble products being mixed without CLEAR guidelines.... No lives lost this time but scary close.
@@underwaterdick the benefits of general education. I also find it insane that anyone calling themselves an engineer has never heard the term. This is highschool level chemistry.
Ppm is quite common in a lot of areas. Ships have oily water separators that are not allowed to discharge more than 15 ppm non water by volume (measured by a photocell). Similar, boiler water chemical dosing is measured on ships in in ppm CaCO3 (a so called p-alkalinity test). I've come across ppm quite often. We don't dose biocides by ppm but I'd understand the concept if I was presented the problem.
Hell, I *DO* know what PPM means and doing it by mass for a fuel addition sounds entirely reasonable. Serious failure by the technical writer there, leaving out the word 'volume'
I agree with you. But in this case, it would not have made that much difference (the density is not that different, so maybe factor of 1.25-ish). Funny enough, the creator of the video failed to spot the mistake as well. Try calculating the 100 ppm of 6200 kg yourself and you'll see :) because 0.01% is not 0.01 of the original mass...
Exactly my thoughts. I'm a pharmacist, so I'm trained in this stuff and I would also assume it's a mass, not volume, unless it's stated somewhere in recipe/manual, etc.
I feel that this additive being designs around volume of fuel is just poor by design. Planes don't general consider how many gallons/litters of fuel they have, it's all about pounds/kilos. Or in some instance how many minutes.
An ignition problem should theoretically not affetct the engine when it has started already. There are a lot of parts used for ignition only, that can get fixed when they land on the new location. But yeah, they should have investigated the problems before flight
@@norwegianmountainbiker236 They could have assumed the spark plugs or the APU's compressed air had a intermittent problem. Because they re-tried it, I'm assuming the fuel readouts didn't have any discrepancies at the time either. Hence why they took off. They probably felt comfortable about it after the ignition. However I am questioning some things. The engineers don't seem to know very much about their own fleet and even the incorrect mixture of Kathon could have been caught. It seems that the person putting Kathon in was given poor training and possibly poor communication. Ontop of this it's proven the poor training is real because the inspection engineer didn't know which engine procedures to chose. It should also be investigated if the readings showed any discrepancies to determine if these pilots were paying attention. Lots of negligence and I hope that Titan Airways gets investigated further to determine if these engineers are negligent or if the company is negligent.
You've made the same core error the engineers did: 100ppm is 0.01%, which is one hundredth of a percent, or 0.0001. 0.01% of 6200kg is 0.62kg, which is why they put in on the order of a hundred times what they should have. Note the proper amount of kathon, according to the incident report, was 0.8kg. So "by volume" only leads to an increase of about 30%. This makes sense because kathon is about 30% denser than the fuel. Edit: fixed typo of number discussed in replies.
Uh, TemporalWolf... Isn't 100 ppm (0.01%) 0.0001 of a quantity, not 0.001 of a quantity? Multiplying 6200 kg by 0.001 gives 6.2 KG, not 0.62 KG. Still, a 10 X overdose is a heck of a lot better than a 100 X overdose! I am an electronics / electrical / computer engineer not an AME so take what I have to say with a grain of salt: I have always thought of "100 PPM" as "one part in 10,000". Thinking of it this way seems to make the quantities required clearer in my mind. If you have 10,000 KG of fuel you add 1 KG of additive to get 100 PPM. Easy to ratio it from there. I would probably have missed the fact that the ratio was to be by volume rather than mass but the ~30% error would likely not have prevented the additive from doing its job nor would it have caused problems with the engines. I find it unbelievable that the people working on this aircraft didn't know what PPM meant nor where they capable of simple mathematics. I agree that the instructions on the additive should have been clearer, that the procedures manuals should be clearer, appropriate mixing equipment should have been available, and that supervision and/or available help should have been better. All of these things would help a person with good basic education (high school maths, physics, chemistry, etc) and average intelligence perform an unfamiliar task and the fact is, sometimes you do have to accomplish unfamiliar tasks. Unfortunately training cannot anticipate EVERYTHING a worker may have to accomplish. It would appear that these workers did not have a good educational foundation or a good "feel" for the situation they were getting themselves into. Knowing when you're getting yourself in too deep for your level of knowledge is a very useful skill to have!
@Vincent Sullivan I think the "0.001" instead of 0.0001 is a typo in the comment, because 0.01% for 6200 kg is indeed 0.62 kg, as TemporalWolf wrote. As you say yourself, since 100 ppm is like 1 kg for 10,000 kg, then for roughly half of 10,000 (6200kg) we should use roughly half a kilo (0,62kg).
Indeed. Specifically, the video makes the same error as the engineers at 7:26, with the incorrect statement: "They were adding around 6200 kg, or 13 000 lb, of fuel into the wing tanks. 0.01% of that is about 60 kg, or 130 lb."
This reminds me of the Gimli Glider story; where overnight, Canada changed from Imperial to the metric system and only fueled a plane with approximately half the fuel required to make a trip.
Something similar happened with one of the early Nasa Mars orbiters, where two different metric units produced the wrong trust sending the spacecraft into outer space.
@@j.jwhitty5861 Lesson learned for all three incidents: Switch to one unit system, and keep it that way. PPM is no where to be seen in the metric or imperial system. There are mol, kg/L, kg/kg and L/L. :)
@@j.jwhitty5861 There was a mistake with one of the early Mars landers where a european group of coders working on one part of the probe's programming quite sensibly wrote their math assuming metric units, and an american group of coders working on a different part of the programming wrote their math assuming imperial units. My high school physics teacher worked on the geological portion of the probe (unrelated to the first two sections) and was _pissed_ when the thing burned up on reentry.
ya , now all us canuks need to own two complete sets of tools , imperial and metric. oh and if you own a british motorcycle three sets , never forget " whitworth " . thank you mssrs turd-oh , senior and junior .
Everyone is criticizing the “engineers” for the parts per million screwup, but I think that they didn’t know there was two different model engines used by the airline was more important !!! And with two different mixing methods for the two different engines needing differing equipment that they were not provided with, was negligence in their training by the airline. .
@Jannie KirstenThey surely knew what ppm was, but they didn't know how to use it. Do you know how much salt you need to put in a litre of water to reach 1000ppm ? Me neither. Specifying concentration (or anything else) in dimensionless units is dumb, because it leads to this kind of errors. Does it mean ųmol/mol ? mg/kg ? You can't know.
I think the real problem with the wrong engine type, was that they found the diagnostics instructions would never have found this problem on that engine type .. the diagnostics for that engine type is INCOMPLETE... its ANOTHER problem, caused in tardy revision of the diagnostics instructions. This is crucial as the kathon will be in wide spread use now, due to long term storage of planes.. the new engines had the problem covered in their instructions, the old engines didnt!
At first I was surprised that trained engineers didn't know what PPM meant but even if they did and correctly calculated the volume or fungicide they needed, without clear instructions on how to administer and evenly disperse the additive into the fuel is a huge oversight. I can't imagine how stressed they were trying to figure this out with all of the time pressure they're put under.
The reason that they didn't understand is because "engineer" gets slapped onto the job description of any grunt who passed high-school and had some on the job training sometimes, when the correct job description should often be more accurately given as technician or just maintenance grunt, hell, some places will slap operations engineer on a janitorial supervisor role and call it a day.
I'm a dumbass truck mechanic and I knew what PPM meant. That's probably because in California we see it a lot in emission controls. We don't have to deal with it but we know what the reference is.
You remind me of a sign I saw in a Tattoo Shop once upon a time, "Good work ain't cheap and cheap work ain't good." Another pro-tip is "Never EVER rush a tattoo artist!" (or really... any artist for the matter)... BUT the industry just gotta keep f**kin' around to find out, right? ;o)
I’m training to become an aircraft engineer and the main thing that they keep telling us is that don’t do anything if you’re not sure or if it’s not in the manual
As a LAE good luck with your training! I hope you picked up on the big thing everyone is missing, even if they had all the formulas to do the calculation they would have still had to google the SG of the additive. Don't ever google your approved data! If you want it and you don't have it (even a material data sheet) stop and stamp your feet until you get it. It's your approval and you hold that approval for a reason and if you say it don't fly, it don't fly.
@A Saga - Exactly .. there are NO stupid questions when dealing in aviation and potentially holding peoples life and safety in your hands. People always look at the pilots first when human error is involved in investigations but most human error occurs on the ground. No pressure 😊. Good luck with training.
As a long time airline pilot, thank you for diligently maintaining the aircraft and not doing anything you aren’t sure how to do! Good luck on your training!
This is a complete and utter failure on multiple levels. The instruction manuals, maintenance manuals, tech training, and so much more. I'm just glad that no one was hurt.
I don't thing the engineers who did the biocide treatment are to blame, company procedures and documentation are. It seems odd to me that biocide treatment should not be part of the engineering training after all bio contamination is common in diesel / paraffin based fuels. Oh well, nobody died!
not providing adequate mixing equipment is my main concern. If someone at any level would have had to design a mixing kit, they would have relazied that they are literally handing fuel and that they need to provide a lot of very clear and strict instructions on how and where to do that. Also the cup that would be part of the mixing kit would be indicative of expect amount of chemical volume.
farm workers are confronted with the dilution of herbicides and pesticides daily - most are unskilled but the blend is vital so someone is o hand to supervise.
The company culture that did not make sure the engineers stopped when they had no exact known procedure... That's the problem. Instead they winged it and people nearly died. There's something toxic in this maintenance company.
I think they deserve _part_ of the blame. We're talking airplanes here, not cars. An airplane doesn't just stop at the side of the road, it _crashes_ if the fuel is fucky. "We're supposed to mix some new stuff into the fuel that keeps the planes in the air... what's the worst that could happen?" Shrugging it off and try and see what happens isn't the right answer here. The instructions were horribly awful, there is the real problem, but it's on the engineers to say "stop, this isn't good enough".
Given that they googled a ppm calculator, not the definition, it's possible that they knew (generally) what it was and just didn't remember how you calculated it. I also learned what ppm is in high school, but I wouldn't have remembered whether to use volume or mass or mols to calculate it, because I haven't used it in years. Regardless, it's absolutely inexcusable that neither the packaging nor the maintenance manual had specific instructions (how to do the calculations and how to mix it with the fuel). Especially the maintenance manual. It shouldn't be skipping any steps, ever. Add to that a lack of training on this procedure, and it was only a matter of time before somebody did it wrong.
The fact that 2 mechanics made essentially the same mistake is an indication that the training and manual were inadequate, but I have serious concerns about the one who felt they needed an online calculator to get a percentage from powers of ten.
@@yowtfputthemaskbackon9202 I'd just feel a lot safer if I could be confident that the professionals maintaining dangerous materials/equipment that I depend on for my life can at least do the easiest arithmetic possible, especially when they're the only one who can possibly know with any certainty what they did. I can count the pills I get from the pharmacy, but I can't double check the ratio of fuel and additives that someone else dumped into the aircraft I'm aboard.
@@starcrashr as said fuck ups are fuck ups, its basically impossible to make shure something like this wont happen. unless you have a machiene, in which case the issue becomes that machienes arent self corecting, if they make a mistake, they often have no way of identifying that they made a mistake where as humans have the ability to check for any sort of unusualities. so either way, eventually something will go wrong. thats the way it is. it doesnt mean that there shouldnt be consequences for the parties involved, however it is still an inevitability.
This is actually REALLY weird, their first goof was in treating 0.01% as 1%, so, I'm not sure how they ended up with 38x rather than 100x (the second being not mixing it). The volume vs mass for the ratio is a much less significant error *ponder*
Damn, man, that's a pretty big and crucial thing to know in any kind of mechanical maintenance field. Concentrations of contaminants, emissions levels, etc. It also a very weird way to give a concentration for an additive. You'd think they would give it in X amount per liter/gallon. I have used coolant additives that I had to test for a concentration in PPM, but they always gave the needed amount as per gallon of coolant.
Giving a sample mixing ratio with arbitrary amounts (bags, barrels, etc.. non-base units) without giving the PPM or % ratio directly is just making things more error prone. The problem is that one have to figure out the ratio first from the sample to apply to the value he has to work with, which is an extra step to fail. PPM or % is directly applicable to a value and the outcome is what you need. If someone can't cope with this, it's a sign, please get into another profession. The only precondition is that the documentation should show the units in what the actual material is usually measured in. So if they measure fuel in kilos and it's weird to measure in liters in that field, then do not give a volumetric ratio to them. If the mix has to be that precise that it can't be precalculated because the variations in specific gravity by temperature or by manufacturing spread etc. has to be taken into account, then all these data should be in the detailed datasheet along with a proper procedure to follow to make it right. Workers in technology fields should beg for and read datasheets and instructions, it hss to be a natural thing for them. If it doesn't --> choose another profession. By the way, there is no excuse for the "engineers" not knowing PPM. That is such a basic thing. Even if they are mechanics only, as someone said in other comments. People used to think that a smarter than average careless Joe car mechanic has a chance to touch an airplane. Why these people get into this field, if they do not know basic things at that age? I don't even understand why people get into technology fields in the first place, which is known to be widespread today, known to be evolving fast so even more wide tomorrow, it is interesting (supposed to), yet they do want to fish in troubled waters only with their limited knowledge and don't care to learn something new in every second? It is such a paradox to me...
@@gabiold my thinking is that the volume concentration is probably what really matters for effective killing of the bacteria, so it's best to give the ratio by volume so you can use it for multiple types of fuel without needing a table. I don't know about the exact product mentioned in the video, but I imagine that if it's fine to go in a jet engine using kerosene, it's probably also fine to go into a piston engine using avgas. In that case, the volume concentration would be more useful than the mass concentration because it stays the same no matter what plane you're treating.
@@tissuepaper9962 I can't debate on that, because I do not know these products either, but I am saying in general, if they measure the fuel by mass, then it would be less error prone to give the ratio as mass ratio. I assume from "bag" packaging that the additive is a powder, which is also better measured by mass rather than volume. Maybe it is suitable for a whole lot of applications in various fields, so it's datasheet might can't list the ratio for a plethora of materials, but maybe the maintenance manual specific for the airplane, if that prescribes that disinfectant, could indicate a precalculated, converted ratio, to the units specific in the field, to the type of fuel, etc... I know, it seems there are more serious problems, namely they don't even know what kind of plane they work on, so they may still would have failed, but it would still be better to reduce the possibility of error... That's the whole story of life. You can never be certain in anything, but you can improve the chances of success with good approaches.
@@gabiold that's true, there should have been a specific procedure in the maintenance manual, and the mechanics should have at least known which manual to look at.
yeah same, the reading ones are fine but I love the narrations here and over at disaster breakdowns and mentour, especially considering they a sound so different. get some Scandinavian, some British, or some North American, depending how yr feeling.
Dude yes im sorry but this is RU-vid, if I want to read I'll just find the other articles or ADMcloudberg. I love this channel for being the one with the balls to do it right, even if he isn't George Clooney or Morgan freeman lol
Actually 100 PPM per mass for 6200kg is 0.62kg. The engineer use 0.01 directly which is 1% instead of 0.01%. Actually if he would have use volume instead of mass the mistake would have been even bigger since Kathon is heavier than the fuel.
Exactly. Behind a desk, writing the procedure down isn't that hard, but it's not trivially easy either. Concentration, density, different units, you always need to double check. In the field, with limited time, there should have been a prepared procedure for them, with the calculation steps written down and where possibly prefilled for the types of fuel and additives used.
The procedure in the manual for this issue should have stated what the ratio would be in weight. How many kilos of additive per 100kilo of fuel or something like that.
@@bbmikej the bare minimum necessary to prevent this mistake would have been to replace "100 ppm" on the label with "100 ppm (by volume)", and they couldn't even do that. I think the reason they measured by volume instead of mass is because different types of fuel have different densities. The only thing that matters for killing the bacteria is the volume concentration of the product in the fuel, the mass concentration doesn't matter. Because each type of fuel has a different density, the mass concentration of the product will be different in each type of fuel even if they're all mixed to have the correct volume concentration, so they would have to have a whole table of values for different common types of fuel. It's easier and more succinct to express the correct ratio by volume.
@@tissuepaper9962 The only issue to listing it by volume and not weight is that all fuel in aviation is recorded in weight. When you request gas you don't ask for liters or gallons, you ask for pounds or kilos. Fuel flow isn't liter/min or gallon/min, it's in kilos or pounds per minute. That would just throw even more confusion in. Also, that fuel flow in pounds/min in the US is abbreviated ppm.
In the summer of 2019, I flew on G-POWN twice, when it was leased to Jet2 with a few Titan Airways pilots to fly the thing (Jet2's pilots are only qualified for the airline's 737-800's, 737-300s, And 757-200's) seeing that familiar reg on this video was a shock to me, I didn't expect that at all... EDIT: as a passenger. I flew on it as a passenger.
When you work with biocides, you always do the mix previous to dropping it inside the thanks, wether it's for agricultural, industrial or other use. And that should be stated clearly on the product's instructions.
It would make sense, but when they use a 38th of the amount, it would be more of a powder floating around on the surface of the fuel, that slowly dissolves in. The bag full dropping in formed a mass that just fell to the bottom.
@@isilder Yes, obviously the matter of overdosage is paramount here but only because of its solubility, not because "the bag dropped as a mass to the bottom of the tank". You could be using the correct quantity and still produce aglomerates if you didn't thoroughly mix the product with your solvent (in this case, fuel). And soluble powders are particularly prone to generate this, even at the correct dissolution rates, if you don't thoroughly pre-mix
I feel that there are other factors that might be into play. Time and Fear. Time: Time problem is cause by not meeting the "customer's standard", whatever they are, upper management or pilots ... etc. When you need to meet a KPI, or make improvements, sometimes time will be cut. You are told to work faster, better, with less time. Corners will be cut, and systems not tested properly as a result. Fear: As a "Grunt", where you have no say, and your superiors are "Gods", there was a time where we really did not know the procedure for something. When consulting with a superior, they will ask you back, so how should it be done? ... The question was made to threaten your worth as an engineer/technician. No answers are given to you, you will just have to look for it yourself.
In Britain, and maybe a few other countries, I believe the term "engineer" has an entirely different meaning in this context. As I've watched other aviation documentaries I learned that a basic aircraft engineer is nothing more than a basic A&P in the US. I don't know if they do this to help mechanics "feel better about themselves" or what?
mechanics propably would prefere not to be called engeneers. its more likely to make the people on the planes feel better, since if you say "we just had a bit of abnormality with the engine , our engeneers will check it out momentarily" that sounds much more ashuring then "one of the engines is acting up, but dont worry bob the mechanic will see if he can go make it work" also i think in this case its down to education levels. they are propably actual engeneers by their level of education but perform a job more similar to a mechanics. im just guessing in both cases so idk
The "engineer" part has been in common use in Commonwealth countries for this sort of job for a long time so when the government departments created licensing for aircraft mechanics the term was used and became the legally applicable title. In the UK and Canada the AME license is roughly equivalent to holding both the A&P and IA licenses with the FAA. In Canada there are M1 and M2 licenses (basically light and heavy aircraft) and there are type specific endorsements, for example you could be an AME-M2 with 737-300/400 endorsements. I completed all the formal training for the AME-M license in Canada years ago but never managed to get a job so I never completed the apprenticeship period needed to get the license itself. Actually only one person in my class of 16 managed to get an aircraft maintenance job and get his license (it was a bad time to graduate with layoffs all over the industry). Fortunately it was one of the four people in the class who I would trust in that position - a great guy, skilled, easy going and with real integrity. Some of my other classmates I wouldn't have trusted to flush a toilet properly.
Considering that I only took a year of physics for my biology degree, I would think that someone who has the title of an engineer ought to have known more than I do what ppm means. I knew what it meant so how the hell didn't they!?
Engineer in this case means maintainer. A lot of us have no schooling outside of the Airframes and Power Plant school (or national equivalent) to get the license.
Wow. The context of the calculations themselves should lead anyone to be able to deduce that PPM means parts per million, you’d think. Especially even the most novice of maintenance persons. Surely they ran across that acronym in their orientation if not their initial training.
I'd be interested to know if they were ex-Airforce. In the military, everything is spelled out for an idiot to perform. No thinking required, no thinking allowed.
@@ariffbasri 100 ppm is simple maths. 100 parts per 1,000,000 parts. Which is 1 per 10,000 or 0.01%. The website was 100% right. Simple maths. The problem was (and is) that ppm is ambiguous as it can be by weight, by mole, by volume ... and a few more. E.g. α = 5.2 ppm/°C. The fault is with those people who used ppm without clear and proper indication what they actually meant: 100 μL/L ... and them there is that mixing procedure (or the lack thereof). ... and people not checking which engine they are actually working on. ... and a total lack of "hey, I did exactly this-and-that because all data I had said ABC and I concluded XYZ --- this needs to be added to the documentation (or corrected, if it is not right)"
This honestly points to so many systemic failures: - Why is a plane where fuel flow is erratic even taken into service for another flight? - Why isn't the engineer that could spot the error trained on which engines have? Sure, he could make a mistake, but he shouldn't be able to. - Why did two independent engineers make the same exact mistake, and *both* felt like they could not wait for confirmation of the correct procedures? The last one is the most damning. They both did the same thing, made the same mistake, and both were aware that they didn't know what they were doing - yet were doing it anyway. The engineers did not speak up, wait, nor did the refuse to do the things. This is indicative of so many systemic failures in maintainance.
@@cordfortina9073 That's my point - it's a systematic failure, something the company needs to change (or the authority needs to enforce). It's not "two dumb mechanics" or whatever. It's a system that has pressure where there should be no pressure. Instead of pressure to do the job right, it's pressure to do the job fast, even if it's wrong. That is caused by wrong incentives, not by people being dumb.
correct, how could they fly a plane when they did not find the cause of the erratic engine behaviour ? that should be a "return the plane to the manufacturer" situation !. the diagnostic for the wrong engine type is MISSING this possible cause of problems, the extreme fuel contamination issue, even though its for a different engine type, I'm quite sure that no engine will cope with having that much contamination in its fuel, and the gunk in the fuel flow will cause any engine problems. They would have had the problem still if the engine was of the type that matches the diagnostic plan they used. Only if they used the diagnostic to match the NEW engine type would they have this situation covered. He's exagerating the significance of the engine type issue. Its like saying a "oil pressure light " can mean different things on a Honda or a Toyota. (ok, it could be a false alarm due to a specific vehicles problems, but it MEANS the same thing... )
I also don't understand why the fuel flow errors where not connected to the recent service that was done on the plane. You replace the alternator on your car and your getting erratic voltages on your dash.... wouldn't someone put 2 and 2 together...... Hey bob (pilot) we are getting a fuel flow error on the computer.... (pilot 2) Was there any recent services done on the aircraft? Or I would think there would be some kind of system in place to inform the pilot of any recent work that may have been done on the plane or something to maybe hey watch out for..
7:30 You've made exactly the same mistake that the engineers themselves did. 0.01% of 6,200kg is 0.62kg, not 62kg. That's an error of a factor of 100, and far more significant than the fact they did the calculations for volume not mass.
Yes. I'm not a mechanic or engineer but knew what ppm meant. It is rather worrying to hear that the folks working on aircraft don't know such simple things... makes you wonder what else they don't know.
From what I understand, they knew PPM means Parts Per Million but thought they could make the measurement based on mass whereas it should have been based on volume. When different chemicals have different specific gravity values, mass is an unreliable measure. Try weighing 500mL of water and 500mL of hydrogen peroxide and spot the difference. Yes, almost everyone knows what the initials PPM mean, but is it w/w, v/v, w/v, v/w? You wouldn't know that unless someone told you or, more importantly, it is specified on the mixing instructions. As for dumping it straight into the fuel tanks, that was a bit silly but still, no-one said otherwise.
This will soon get extremly worse after the money losses due to the f... pandemic, ...low costs count, I don't want to know who soon will work as "engineer". Will cost lifes sooner or later.
Yeah, was going to say, "ppm" is a pretty common term in engineering, speaking as a chemical engineer myself. For a trained engineer to not know that acronym would be pretty surprising to me.
He might be an engineer but planes replaced trains and Google replaced brains. Did the instructions stipulate ppm by volume or ppm by mass? Anyone who thinks it is OK to put a powder into fuel tanks on the plane has other thought processes that need checking.
Yes but there are cardinal rules: you cannot do anything not clearly defined in a procedure or improvise if there are gaps in a procedure. This may well be more likely to happen with experienced engineers as they may believe they have more scope for using discretion. But there should be no discretion when doing standard tasks like this. There should be only one way of working (the right way) clearly defined and documented and you follow it to the letter (no matter if you have a community college degree or a PhD from MIT). if there are gaps in the procedure or don't understand it or haven't been trained in it you stop immediately and escalate.
Thanks for video, but you have skewed the true story (and so cause). 1.Instructions said Kathon ppm calculation was by volume. But it would make no difference. See, the density of Kathon 1 kg/L is almost the same as for jet fuel 0.8kg/L, and there will just 20% difference, calculate by mass or by volume, which is acceptable. 2. Much more important, the web calculator gave the correct answer for the technician: 100 ppm is exactly 0.01%. The problem was technician's perception. He mistook the correct answer of 0.01% - as factor of 0.01 (which is 1%). So he put 100 times more Kathon in fuel. He should have added just 0.6 kg, instead he added 60kg. Calculation by volume would give 20% error, which is just extra 0.12kg - negligable amount, compared to the error of 59.4 kg, made by the technician who forgot school math. 3. Yes, clear instructions were missing, but then - they should say: “WARNING to Technicians and Bloggers! Never mistake fractions of a percent for a factor!” Don't shame yourself, but you made the same mistake as this technician! The 0.01% of 6200kg is not 62 kg as you say in your video (7:30), but just 0.62kg. Its a hundredth part of a hundredth part, not just 1%. Its hundred times less than one percent! (See, a hundredth part of one percent can't give the same amount as one percent!) Scary - the level of elementary math of some aircraft technicians is the same as for innocent RU-vid bloggers. Cheers! assets.publishing.service.gov.uk/media/6087c670e90e076ab1e3492c/1-2021_Airbus_A321-211_G-POWN.pdf See page 22.
And DuPont now recommends against using Kathon FP 1.5 in aviation fuel www.ainonline.com/aviation-news/business-aviation/2020-04-14/faa-issues-jet-fuel-biocide-saib
Great job! Just a small remark: this aircraft (G-POWN, A321ceo) is in fact equipped with CFM56 engines, and not CFM LEAP. It's the A321neo that uses the LEAP engines :)
The 2nd engineer *DIDN'T* believe the Internet & was dubious about the calculation result, which is why he turned to other resources and to the other engineer. The problem was that he couldn't find any authoritative resource, and he made the mistake *MANY* engineers make across all disciplines, that being, believing his own flawed logic without any way to verify... AND proceeding even though he had serious doubts. The other factor is a fear of being ridiculed over something he felt he should know -- so he covered his butt by being a pretender.
@@hack1n8r Yeah, he thought it sounded like it was too much, and it was, because the instructions didn't specify that it was ppm by volume. His gut feeling told him something was wrong, but it's not the internet search or the calculator that was wrong, it was the procedure that didn't contain enough information.
Thank you. When you said PPM, I immediately thought, PPMV? Or what? I would put the corporate executives in the root cause analysis path. They have poor training system ? The technician did not even know what planes his company flew. And no cross-checks to ensure that the procedure was done properly. This sloppy operation is a hallmark of profits before safety.
Every time somebody brings this incident up, people are amazed that the engineers didn't know what ppm meant. And yeah, it's weird that they didn't, but the fact that there's no tables for them to calculate how much biocide to add or written instructions on how to mix it in is one hell of an oversight. Every procedure needs a documented SOP, to prevent exactly this kind of mistake.
I think part of the problem with the ppm by volume / weight confusion was caused by the fact that aviation fuel is almost always quoted by mass (pounds), rather than volume. And in fact since the volumetric density of fuel varies significantly with temperature, one would expect anything to require a degree of precision to use mass. But then maybe I'm overthinking this one!
The lack of documentation about how to properly perform this maintenance activity and the lack of proper procedures and equipment to do so is unquestionably bad, as is the lack of oversight that would have caught this. That said, in defense of the engineers, most concentrations of chemicals are specified by weight, not volume, so that was an understandable mistake.
Agreed. As a chemistry teacher, you can bet that 99/100 times when we're mixing dry solid chemicals into a liquid to make a solution, we're using calculations with mass as the basis, not just volumes. While they did make an error/mistake in their maintenance, they only did so because they were denied the resources to properly understand what to do, and they couldn't find any assistance from their more experienced coworkers/superiors when they went searching for it after recognizing the limitations of their abilities in this situation.
No it wasn’t ,the engineer should have known the basics every flight depends upon the competence of the engineers It relies on common sense and ability
Also, if two engineers independently make the same mistakes, both knowing they're doing something iffy, then it points to bad company culture rather than individual mistakes. They didn't start randomly googling "how to repair aircraft for dummies" at the same time by themselves. They even asked each other, yet did not feel like they could wait for a supervisor before carrying out the procedure. It's a shame, really.
@ Johnathan and Matthew : _"in defense of the engineers, most concentrations of chemicals are specified by weight, not volume, so that was an understandable mistake."_ Everybody here seems to be making _that_ the crucial error, and it wasn't. For all practical purposes, it doesn't matter whether the subsequent ppm conversion was to weight or volume. The fact of the matter is that the technicians' initial understanding of what 100 ppm was, was off by a factor of *_one hundred_* due to a math error by the technicians. (Failing to understand that 0.01% is not the same as 0.01) Whatever difference in specific gravity exists between jet fuel and Kathon, it's nothing in comparison to an error of putting _one hundred times_ more Kathon in the tank than they were supposed to, whether it's a hundred times more by weight or a hundred times more by volume. (And of course, there's the fact that they just dumped it into the tank without even mixing it with the jet fuel. That made an already bad mistake far worse.)
I don't know where you live, but you upload all your videos at 9:30ish at night in Australia which is just when I'm starting to wind down and play some games and listen to some videos. It's absolutely perfect for me
That seems to me to be a documentation deficiency, both on the part of the Kathlon packager and the airline. Keeping the techs informed of the aircraft types in the fleet and the procedures required would have been a good idea, too. (It's possible the manuals were written when the fleet was homogenous and not updated when that changed.)
30 years doing aircraft maintenance, I've worked on more aircraft I wasn't trained on than ones I had full training on, especially on the airlines where I did contract maintenance for 14 years. I was given the manual printout that explained what to do in each case. Something like this would have caused me to call someone up the chain, all the way to the aircraft manufacturer tech support if required
I am surprised that the Engineers didn't have any background knowledge about PPM. That is something that is covered even in high school level chemistry courses so it was something that they probably should have already been taught.
Don‘t know how it‘s like in the rest of the world but in germany we can get our higher education „Abitur“ (which I don‘t think you even need to become a mechanic) while leaving out chemistry for your 2 final years i.e. you final exams will contain no questions about chemistry. So I for example haven‘t heard of PPM even though I have my Abitur, meaning I went to school for 13 years.
You don't need to be a sleuth someone else has already done that. This was an "incident", there will be an Incident Report. www.gov.uk/aaib-reports/aircraft-accident-report-aar-1-slash-2021-airbus-a321-211-g-pown-26-february-2020 Hurray for governmental transparency!
I'm not an engineer but a retired Pilot. Almost every incident or accident goes back to training, training......and the lack of or complete absence of it.Excellent video and content, thank you.
I think engineers must do work either: In teams where, at the very least, one knows and mentors in the task to be done. Solo where, the solo engineer has done the work a few times, enough to understand what he has to deal with. Ofc, also the manuals must explain some of the obvious as attachments and must explain straight away the requirements (such as when the fuel has to be injected mixed). It's actually easy and short to mention that: "Externally mix the [substance] with fuel and then feed the mixture to the aircraft". Clearly an oversight on who did the manual!
It's common knowledge as far as I understood until this video. Somehow a hanger dull of engineers didn't know something I knew before I ever picked up a wrench.
@@ZephyrGlaze Bruh I got chemistry and biology and I never heard PPM. Not everyone learns the same thing so why u expecting everyone to know it. If it wasnt included in their course then how do you expect them to know it
ppm is a pretty standard engineering term, but it can be by weight or by volume (often entitled ppmw or ppmv). If the procedures didn't state this, including the instructions for use with the chemical, they are seriously flawed. Normally, though, weight and volume ratios are not greatly different and using the wrong one would not show up.
I once worked in a maintenance capacity for a builder (houses etc.) Generally where new houses are being built, there is no electrical power - which gives a choice of a couple of solutions. Either have an on-site generator or use power tools with their own small engines. The firm happened to use both solutions - they had saws with 2 stroke engines and one diesel engined generator and one petrol engined generator which was a 4-stroke. The 2 stroke engines have a little oil added to the petrol to lubricate the engine. The 4 stroke generator did not. It meant they needed to have cans of petrol for both types of engine - and mix-ups happen ! It wasn't long before the 2 stroke engines got a refill of neat petrol - probably the last tank of fuel they'd use. After that, they wouldn't start due to worn engine parts. The company boss bought 3 new saws with 2 stroke engines and on bringing to the maintenance dept for initial commissioning, explained the problem. As all the petrol came from the maintenance department, we suggested that all cans of fuel had oil added. Ideal for the 2 stroke engines and 'OK' for the 4-stroke - which may be a little smokier but not doing any harm So why not add biocide before it gets delivered to airports ? Possibly less would be needed if always present but it will add to costs - but surely better than having a plane crash !
More seriously: I'm a bit confused by the role played by specific gravity in this mess. The correct mass of Kathon to use is the mass of fuel, times the ratio of specific gravities, times 0.00001. If you do that calculation you get 0.799 kg of Kathon per wing. Now, if you leave out the specific gravity ratio as a factor, and calculate ppm by mass instead of by volume, you actually get *less* than that: 0.620 kg per wing. So that should have meant the engineer slightly underdosed the thing, rather than grossly overdosing it. Meaning that the by volume/by mass thing is actually pretty marginal, no? The main issue is that he must have done the ppm calculation wrong, no doubt through not knowing what ppm meant. How on Earth did he come up with 30 kg, I wonder?
Thanks for the Video :) I think an engineer is someone who knows how to learn stuff rather than just knowing things. That said, I think in situations as sensitive as this, it would be wise to have a fallback procedure that consults personnel that have the explicit experience.
First of all, I suppose that the persons doing that mistake were mechanics (technicians or something related) and not engineers. As the problem considering the wrong amount would have been obvious to an engineer - who should be able to understand what a per cent means (1/100) . I suppose also mechanics do know what a percent means. And the first problem lies here - in the misunderstanding of what a per cent (%) is!!! As they just dumped 60 kg of Kathone into ~ 6200 kg of kerosine. Not 0.01 of a per cent but the whole per cent!!!! So 100 times too much. Second, they also couldn' t count to two, because luckily the total amount of fuel was 6200 liters per wing fuel tank, so 12400 liters in total (thanks, Alealactaest2009). So just 50 times too much (weight) instead of 100, great! So to summ up, before considering different kind of possible fractions - this was not a problem with the informations found in the internet. More like reading comprehension or not forgetting about units like per cent. And not using the correct method of mixing the fuel with the kathone might have contributed. The website has given them the information that they should use 0.01 of one percent. Yep, 100 ppm is 0.0001 so 0.01 of a per cent. What kind of fraction? weight, volume? Compared to the first problem with ~ 100 or 50 times more almost irrelevant in this case. They used weight. With the density of kerosine of around 0.8 kg/l and Kathone of ~1.02 kg/l the deviation (1.275 times more Kathone) would be almost negligible as compared to a factor of 100 or 50. So messing this up actually played in favour of the ground personal and reduced the amount of Kathone added to just ~ 78 times too much (for one wing tank) or ~ 39 times too much for two wing tanks. But around 40 times too much was still too much... And even the molar masses of Kathone (Methylchloroisothiazolinone) of around 150 g/mol and around 170 g/mol for kerosine are not that different, so if a molar vraction would have to be used that would also not have been that critical.
The AAIB report states that: "Fuel uplifted: 6,200 kg (per wing tank) With a Specific Gravity of 0.80827 = 7,678 litres, 100 ppm = 0.0001, 7,678 x 0.0001 = 0.768 litres of Kathon Using a Kathon Specific Gravity of 1.04 = 0.799 kg (per wing tank)" So that would be 1.598kg total and the engineer used 60kg total = approx 37.5 times too much. That's an approximation and the more accurate figure stated is that, "On completion, the Kathon-dosed fuel had a bulk concentration of 3,814 ppm" (which is where the 38 times too much in this video comes from). assets.publishing.service.gov.uk/media/6087c670e90e076ab1e3492c/1-2021_Airbus_A321-211_G-POWN.pdf (See 1.6.7.9)
I'm an engineer in another field and I did know what PPM meant. Nonetheless, I think the most significant missing information is not the meaning of the acronym but what it refers to, mass or volume. In the chemical industry, ppm usually refers to mass.
At my work we used Kathon to prevent spoiling of a polishing substance we make. It have now been replaced with safer alternatives as Kathon is seen in general as an environmental toxin to be phased out. It was the active ingredient in many now forbidden toxic boat paints for keeping algae and molusks from the hull. It is also used as preservative antibacterial agent in things like mascara, shampoo and other similar things. As it can cause severe contact allergies this use is also on the way out. Our Kathon came in liquid form but appearently in its pure form its a brownish waxy substance which was what clogged the engines and valves up. It is a mix of the chemicals Methylchloroisotiazolinone and Methylisothiazolinone.
As a doctor, I can confirm that this is a real issue. Abbreviations! There are so many of them and used in weird ways, it's quite impossible to know them all. I really hate them. Because they can lead to errors. I personally never write abbreviations.
Do they vary between regions, countries, companies (for private practices) etc? To oversimplify, I'm in the computing field, and some of the companies I've worked for use the acronyms in very different ways. I don't mind that toooooooo much. But I find it particularly frustrating when I strike someone who assumes that's how it's done everywhere, and you're stupid for asking.
@@FunnyHacks yes. Abbreviations vary a lot. They vary between different fields of medicine, even within a department under different situations there are the same abbreviations with different means. The worst of all is that you can make your own abbreviations if you're publishing articles etc. And there seems to be no regulations on this. I feel really frustrated. Also different countries use different units for lab values. It can even vary between lab to lab. And some labs don't even write the units. It's crazy.
Its really strange to me that it was in volume... and well.. while it would seam pretty obvius to mix it outside of the plane, this really should be stated in the manual. To me it seams like a really poor manual
The manual states: "refuel all the fuel tanks to the maximum capacity, with fuel mixed with Antimicrobial Agent-Fuel System Liquid Additive” The accident report speculates, with reason I suppose, that the engineers didn't think it was wrong to put the fuel in first and "mix" in the Kathon after was because the engineers in question spoke English as a second language and didn't properly get the difference between present simple and past simple.
I used to work at an aircraft scrap yard, and i have seen many "schoolboy errors" made by highly trained and highly regarded service technicians which could have caused absolute disaster, but thankfully didnt, everyone makes mistakes from time to time One was a pair of work overalls which had been dropped into a fuel tank, maybe through an inspection hatch This could have happened during a maintainance crew change, it happens, aircraft skin is slick, its meant to be for better aerodynamics If a technician has taken overalls off, say if he was hot, or to get into a tight space, and left them on the wing, a gust of wind could have blown them into the open inspection port These overalls may have been in that wing tank for months, thankfully they only caused problems during the very last flight of the aircraft The overalls wrapped themselves round one of the fuel filters/pumps, and caused a blockage This meant that the aircraft had to fly straight to the breakers runway, rather than do a commemorative flight, landed with 10 tons of excess fuel on board, no big deal, it wasnt over its landing weight, it just meant more fuel to remove from the aircrafr before we could work on it Thankfully, there are fuel redundancies built into aircraft, so the pilots just used a different tank to supply the engines on that wing Made a normal landing, no problem If however they were due to fly a transatlantic flight there and then, they may have had to divert or ditch due to fuel starvation and flame out of the engines, depending on when the overalls got wrapped round the pump during that flight
Remember Air Canada flight 143, “the Gimli Glider” in 1983. Miscalculation of the fuel load led to the plane running out of fuel halfway between Montreal and Edmonton, at 40,000 feet. The real root cause was upper management. The pilots were heroes.
I wouldn't loan my 2 Cycle mower to any of the Engineering idiots. They would prolly read "Ratio" as the brand name & figure the numbers and colon are for Braille readers.
@Harry, in a broader sense I have to disagree. The whole "definition" of engineering is about finding solutions. Sure, these particular engineers screwed big time when they put 1% instead of 0.01% (the converter was OK, and the video did not explain this error well either, which is a shame, but the volume vs. mass would make a difference factor of about 1.25. On the other hand the 62 kilos instead of 0.62 kilos (which is the real 100ppm of 6200kg) made a factor of 100). So yeah, if I was the engineer and read the manual saying only to put it there (nothing mentioned about mixing it beforehand), I would not say it's the lack of an expertise, it's clearly lack of instructions (in the manuals both for the plane AND for the additive). So... this case is not about expertise per sé.. it's about basic math and good manuals. But sure, engineers should be competent enough. I just wanted to say that good engineers should be creative enough and find new solutions. Of course, not trying something unproven on "live environment (hardware/software)" if there can be consequences. But not refusing to do anything just because they haven't seen it before. Of course, the competence that I mentioned earlier, includes doublechecking your calculations etc :)
Hadn't heard of this one, felt such relief when you said everyone landed safely! It always amazes me when accidents or near accidents seem to be caused by subtle errors and misjudgements, it seems inevitable, but also completely avoidable - suppose thats human error for you
I’m a Mechanical Design and Applications engineer that primarily works in aerospace, and the most shocking element is that TWO flight maintenance engineers didn’t know what ppm means. Scary. I can certainly understand not being familiar with the procedure because of limited information and trying to use any available resources at your disposal to accomplish the task/fix the issue, I run into similar issues on a weekly basis when some of our CNC manufacturing cell stations (VMC’s,HMC’s,Mill/Turns, etc. ) fail or have faults. The machine tool vendors often supply very limited prints, procedures and ladders, so to me that is forgivable on some level... but to not know the definition of the volumetric ppm? Sounds odd.
There was also mention in the report that the stores person did not question the unusually large quantity of Kathon being drawn. Another step towards potential catastrophe. As in most cases, it's a chain of events that could easily have been broken.
7:32 and 7:37 Boy, it's a conversion error, for 100% = 1.00, thus 0.01% = 0.0001 = 1/10000 Therefore 6200kg x 0.01% = 0.62kg or 13000lbs x 0.01% = 1.3lbs Plane refueling is always done in either kg or lbs, doing things in volume would just add to the confusion.
Everyone comments about them not knowing ppm, but the real issue here was all the other steps. The ppm conversion was the one step that was done correctly. Working with the wrong unit and not mixing correctly were the real problems here.
yep. The airport/service provider should have had a mixing kit/procedure. Imagine handling an open fuel container. Imagine mixing something in to fuel. I know that a lot of safety engineers are pencil pushers - but writing down "this procedure ask be to mix fuel with a chemical, but I do not have a certified bucket and stir" should ring plenty of alarm bells.
Apart from the manual / measuring issues, just dropping the additive straight into the tank and expect it to mix evenly... that's crazy! The fuel mixture is always going to be critical, definitely should have checked directly with manufacturers.
Ya, the product sheet says to mix it inline or with fuel first or at worse fill the fuel tanks after application to agitate it. They also put in 20x the amount they should have.
Lets be honest, the flight crew was great dealing this unexpected problem Always checking whether something can go wrong, and when it went wrong the quickly react and stabilize it
This was a reposition flight. Cabin crew MIGHT have been on board, but I think it was only the pilots and some engineers. So even IF there were flight attendants on board, they sure as hell had nothing to do with anything that happened here.
If you study at a STEM university for any STEM major, especially including engineers, ppm is one of the first terms you will learn the meaning of. I studied Aerospace engineering and I used PPM as a volumetric ratio for many applications. Most notable was any Chemistry based class. In Fluid Dynamics type courses it's used in calculating the properties of certain homogeneous fluids. I could go on and on. The engineers demonstrated extreme incompetence in their field and I am quite honestly surprised they ever got hired. The fact that they did not consider the density difference making a pool at the bottom of the tank is also very shocking. The engineer in charge of inspecting the engine also demonstrated extreme incompetence by not understanding what type of engine he was even inspecting. I would assume you should be familiar with something if you are inspecting it for faults. It's extremely frightening that they were never taught the basics of their career where safety involves the lives of others.
Reminds me of when I worked in a Haematology lab and my colleague was mixing up some Cyanide-based reagent but had got the amount out By factor of 100. He was found merrily splashing around large quantities of this highly poisonous substance. Result was rapid closure and evacuation of the lab but thankfully no harm to himself or other staff.
If you are working on an airplane and you have to google something, that should be a pretty strong indicator that you are not qualified to do whatever you are trying to do. The engineers and their supervisors should absolutely be held accountable for this.
Well, no one is capable of remembering all things all the time… but their training process should have made them more capable of detecting inconsistencies at the informations they’re looking for, no matter they were found at Google or in a specialized book.
Why does the packaging of the biocide agent not contain details like specific gravity? Why does the maintenance manual not contain a conversion formula? These are lapses in manufacturing and design. The airline industry already faces a dearth of qualified mechanics and ground personnel, and so the ones who are already present are overworked. Even pilots get formula references to hand in manuals and things like that. This is not fully the fault of those technicians. It is the fault of the whole system.
They absolutely should have had reference information. The fact that the needed information wasn’t available *should* have inspired them to not do the task instead of inspiring them to google and guess.
@@Berchol yeah... ‘cause a plane crashing and killing a few hundred people is totally going to go unnoticed.... This is why I include their supervisors in people who should have known better.
I'd like to know how often engineers or A&P's perform some task they had not done before, and how often this causes problems. These guys might be "just mechanics" but they certainly are not stupid. Their job is more that just turning a wrench. It requires a lot of problem solving skills. If you have these skills you tend to use them for any problem, such as performing a task you have never done before. Their is quite a strong culture of figuring out how to do it on your own. After all, their job is basically figuring it out on your own. I think the problem here is really more of a lack of clarity on the labels and manuals. How much would it cost to include the correct ratios on the label? Or to print it in a book if the ratio varies from plane to plane or based on the type of fuel used.
@7:32 Ummm… 100ppm, or 0.01%, of 6,200kg/13,000lbs of fuel is 0.62kg/1.3lbs. Not “about 60 kilos or 130 pounds”. Those are 1% or 10,000ppm. I suspect these “engineers” were mechanics/technicians. Folks like to throw around the engineer title to sound impressive (“Ed Norton, sanitation engineer”). But it’s hard to believe even a qualified aeronautics technician doesn’t know what ppm is. (Fwiw, yes I have a BS MechE).
As I’ve said elsewhere, in UK aviation (and some other places) “engineer” is a job title for “mechanic”. The terminology was used in the AAIB report, linked below. assets.publishing.service.gov.uk/media/6087c670e90e076ab1e3492c/1-2021_Airbus_A321-211_G-POWN.pdf
I'm an Aircraft Maintenance Technician and get my hands on Airnav on a daily basis... I would like to add a detail to the discussion, regarding how the technicians got to confuse the two engines. The very first thing you do on Airnav, as soon as you open it, is to set the effectove aircraft. This means all the data displayed will be related to that one specific aircraft you're working on, and this kind of misunderstanding is automatically out of the question. Looking up any info with effectivity set to ALL is a certain way to get in trouble.
Yes, also when u work in airline with mono-fleet (one type of aircraft). U can spot difference between engines at first glance. All CFM have spiral, PW line, on engine cone.
PTM rarely happen in real time, though even in school its not even taught nor mentioned. The only time it was done were on those P-39Q Airacibra based in Alaska during WWII. When aviation industry turned to gas turbines, such procedure was completely forgotten forever as new high pressure fuel pump were available. Its like forgetting more about CRT when transistors become the style.
As a mechanic, I’ve never had to use PPM to calculate volumetric ratios when mixing anything. I’ve only used metric measurements. And the fact that this procedure called for a PPM ratio with no indication of what that meant is asinine. I don’t fault the engineers at all.
