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Topic: Fuel Contamination at JNB
Username: BruceSmith
Posted 2012-11-16 04:16:59 and read 1883 times.

OR Tambo airport JNB in South Africa ended up with seven million litres of contaminated fuel after something went wrong with a pipeline feeding from a refinery. Article at http://www.news24.com/SouthAfrica/News/OR-Tambo-fuel-contaminated-Acsa-20121115 for details.

How often do events like this happen around the world? Some readers commenting on the article in question argued that it isn't an event worth worrying about since they "happen all the time" and it was detected before the fuel was pumped into aircraft.

[Edited 2012-11-16 04:18:21]

Topic: Fuel Contamination at JNB
Username: tdscanuck
Posted 2012-11-16 05:59:34 and read 1887 times.

Quoting BruceSmith (Thread starter):
How often do events like this happen around the world?

It kind of depends on where you draw the line on "events like this". Jet fuel is routinely shipped in multi-product pipelines and you always get some mixtures at the interfaces. The pipeline companies try to sequence the products so that the the mixture is still within spec for one of the products so they don't lose anything...for a long time, diesel would be sequenced around jet fuel because you can mix any amount of jet fuel into diesel and still have it be good diesel. They'd cut over to the jet fuel after all the jet/diesel mixture was passed (low sulphur diesel requirements in the US screwed this up a bit).

So if the event is "jet fuel gets mixed with other things a pipeline," that happens all the time.

However, in this case, it's a dedicated pipeline so that's probably not what happened. It sounds like the refinery either had some off-spec Jet-A (which the would normally sell as diesel or kerosene) that they accidentally sent into the pipeline (contaminating everything in there) or they accidentally sent the wrong product into the line. That's not very common.

Quoting BruceSmith (Thread starter):
Some readers commenting on the article in question argued that it isn't an event worth worrying about since they "happen all the time" and it was detected before the fuel was pumped into aircraft.

I agree that this is not something worth worrying about; regardless of the competence of the pipeline operator, large airport fuel farms have very good quality control. Every one I've seen puts delivered fuel into holding tank(s) and pulls a sample for analysis; they don't release the fuel into the airport fueling system until the tests show the fuel is in-spec. So it would take a whole different slew of independent failures for the off-spec fuel to make it onto an airplane.

Even after all that, for it to actually threaten an aircraft is another set of independent failures; off-spec fuel can be off-spec in many ways. The most potentially dangerous are significant water contamination (damage to fuel system components and/or flameout), off-spec freeze point (fuel waxing at altitude), and particulate contamination (clogging of the fuel system). Significant water contamination is caught by water monitors that are typically somewhere in the airport fuel system and again at the pump trucks. Filters achieve the same thing for particulate contamination. Off-spec freeze point is not monitored or caught in real-time but it's also relatively well protected within the aircraft fuel system...you have to be *way* off before the airplane actually has problems. So even if you got off-spec fuel through the QA checks at the fuel farm, what actually got onto the aircraft isn't likely to be immediately dangerous.

There are other off-spec things that are more difficult to catch. If the thermal stability is off, the fuel control unit may eventually gum up and seize or the nozzles may coke/plug. If the lubricity is off, several fuel system components will wear out prematurely. If the distillation curve is off the fuel vapor pressure may be too high, which can lead to loss of suction feed at altitude. However, most of these require something else to go wrong first (e.g. you need multiple fuel pump failures to end up on suction feed in the first place) or they're cumulative issues that take time to build up, giving you more time to detect what happened and correct it before it causes engine damage.

The whole event is not good, but the chance of this pipeline event threatening the safety of an aircraft is pretty low if the rest of the system is functioning properly.

Tom.

Topic: Fuel Contamination at JNB
Username: Darksnowynight
Posted 2012-11-16 07:09:50 and read 1887 times.

Quoting tdscanuck (Reply 1):
Significant water contamination is caught by water monitors that are typically somewhere in the airport fuel system and again at the pump trucks.

When I used to do that, we never had any monitoring at the hydrants, tankers or static carts. We just always assumed a degree of water contamination and sumped out the systems every 24hrs. Very interesting post though.

Topic: Fuel Contamination at JNB
Username: zeke
Posted 2012-11-16 07:30:27 and read 1887 times.

Quoting BruceSmith (Thread starter):

Depends on what makes it off spec. We think we almost lost an aircraft a few years ago due to off spec fuel, the contaminant was not another type of fuel, it was a substance like cement dust, when burnt in the engine is was like volcanic ash causing the fuel jets and vanes to be coated in a glass like substance.

Topic: Fuel Contamination at JNB
Username: tb727
Posted 2012-11-16 07:33:42 and read 1887 times.

Quoting Darksnowynight (Reply 2):
When I used to do that, we never had any monitoring at the hydrants, tankers or static carts. We just always assumed a degree of water contamination and sumped out the systems every 24hrs. Very interesting post though.

To protect from water at my company, we always test our fuel when the fueler pulls up to the aircraft but that's all we can check for is water. JT8D's are so thirsty, they would probably take it anyways 

I didn't know pipelines were multi-product! Very interesting!

Topic: Fuel Contamination at JNB
Username: Darksnowynight
Posted 2012-11-16 07:54:16 and read 1886 times.

Quoting tb727 (Reply 4):

To protect from water at my company, we always test our fuel when the fueler pulls up to the aircraft but that's all we can check for is water.

We had the option (I'm assuming you probably used the syringe type testers), but it was only ever mandatory for some Operators' ETOPS flights. Once we had a reading of 1A (Dry and Clear), that was considered "good" for the next 24hr on that given equipment.

Quoting tb727 (Reply 4):
JT8D's are so thirsty, they would probably take it anyways 

I'm sure you could cut their fuel with syrup and be fine, 

Topic: Fuel Contamination at JNB
Username: BruceSmith
Posted 2012-11-16 12:18:29 and read 1887 times.

Thanks for the info everyone, especially tdscanuck.

The latest reports is that they have had to flush the pipeline and some of the storage and processing facility at JNB and that pumping might resume tomorrow. Sounds like the refinery must have pushed the wrong stuff down the pipes. No report on exactly what was wrong with the fuel though.

Topic: Fuel Contamination at JNB
Username: nomadd22
Posted 2012-11-16 13:47:31 and read 1884 times.

Quoting tb727 (Reply 4):
I didn't know pipelines were multi-product! Very interesting!

I use to work on a pipeline between Albuquerque and El Paso that passed just about anything in both directions. Some products didn't mix and you'd have a sharp separation between the two when switching. Other times they'd send a pig between two different products. If they had too much mixing there would usually be an industrial boiler somewhere that could burn just about anything with carbon in it or some other non particular heat maker.

Topic: Fuel Contamination at JNB
Username: 2175301
Posted 2012-11-16 14:33:52 and read 1884 times.

When dealing with off spec fuel - a number of the possible problems can be corrected by adding additives. I remember more than once having to add additives and recirc the storage backup storage tanks for a few days to get full mixing of the additives throughout the tank (this was a non-aviation application; but still shows what is routinely done). The additives are not cheap - but usually cheaper than the loss of a tank of off spec fuel. A retest of the fuel is done after the additives are mixed to ensure that it is again in spec.

Have a great day,

Topic: Fuel Contamination at JNB
Username: FI642
Posted 2012-11-16 16:46:27 and read 1884 times.

Normally fuel comes out of the pipe into tanks, where it is allowed to settle for a set period of time. Then it is tested for contamination. When this happens, fuel is tankered, trucked, and other tanks are utilized.

While it happens - it isn't all the time. ASIG does a good job at my field keeping carriers updated and they work their tails off when it does happen.

Topic: Fuel Contamination at JNB
Username: ordjoe
Posted 2012-11-16 17:58:00 and read 1884 times.

Having worked at a refinery and a chemical plant now, this happens much more often than you would think and it a lot easier to cause than you would think. They will probably do one of 2 things, either get a bunch of tank trucks to haul it back to the refinery and re-distill the material (long story, but you can just reverse the flow on a pipeline, trust me on this) or sell it as heating oil or railroad and off highway diesel

Just curious how often do they QC the fuel at the airports and what sort of tests do they run, do the bigger airports have QC labs on site?

Topic: Fuel Contamination at JNB
Username: gegtim
Posted 2012-11-16 18:05:51 and read 1884 times.

I have 32 years of combined experience working with aviation fuel in both the Air Force and the civilian sector. Fuel was always tested and several points: Upon receipt (either tank truck or pipeline); prior to putting a new issue tank online and then monthly Milipores from filter vessels and fillstands. These were basic field tests: API Specific Gravity; visual for color/sediment; single filter millipore an water content (either by Metrocator, Shell or Aqua Glow method.) Storage tanks and filter vessels were sumped daily for water. I only had one incident of fuel cotamination at GEG and that was because the tank truck driver did not properly flush his tanks of dyed diesel fuel before taking a load of JetA.

Topic: RE: Fuel Contamination At JNB
Username: Tristarsteve
Posted 2012-11-17 04:32:30 and read 1885 times.

Quoting gegtim (Reply 11):
I only had one incident of fuel cotamination at GEG and that was because the tank truck driver did not properly flush his tanks of dyed diesel fuel before taking a load of JetA.

A few years ago I used to audit airport fuel facilities for my airline. I made my annual visit to GOT, and the manager was so excited. He had found a batch of faulty fuel deliverd by a road tanker to the airport. This was the first time they had bad fuel in the 24 years he had worked there.

Topic: RE: Fuel Contamination At JNB
Username: jetblueguy22
Posted 2012-11-17 12:13:02 and read 1886 times.

If there is water in the storage tanks how do they get rid of it? Can they just drain a little bit and get rid of the water? Or do they have an additive that gets rid of it?
Blue

Topic: RE: Fuel Contamination At JNB
Username: tdscanuck
Posted 2012-11-17 19:45:17 and read 1883 times.

Quoting jetblueguy22 (Reply 13):
If there is water in the storage tanks how do they get rid of it?

Suck it off the bottom.

Quoting jetblueguy22 (Reply 13):
Can they just drain a little bit and get rid of the water?

Basically, yes.

Quoting jetblueguy22 (Reply 13):
Or do they have an additive that gets rid of it?

There are no additives that are compatible with Jet-A (that I'm aware of) that will remove the water. There are additives to stabilize it and make it less of a threat (FSIIs and microbicides).

Tom.

Topic: RE: Fuel Contamination At JNB
Username: mayor
Posted 2012-11-17 19:55:09 and read 1883 times.

DL has embargoed non-rev travel on the JNB-ATL flight, starting Monday and until further notice, because of this. There's a weight restriction in effect until they move all the backed up cargo. Not sure if they're limiting the amount of fuel they can have, at a minimum, until the problem is cleared up.

Topic: RE: Fuel Contamination At JNB
Username: EK413
Posted 2012-11-17 19:55:14 and read 1883 times.

Let's not forget contaminated fuel is far more serious than we believe it to be... Have we forgotten the BA B772 crash landing when the aircraft lost power in both engines while on final into LHR... The power loss was due to contaminated fuel...


EK413

Topic: RE: Fuel Contamination At JNB
Username: tdscanuck
Posted 2012-11-17 20:17:00 and read 1883 times.

Quoting EK413 (Reply 16):
Have we forgotten the BA B772 crash landing when the aircraft lost power in both engines while on final into LHR... The power loss was due to contaminated fuel...

No it wasn't. The power loss was due to icing in fuel lines that blocked the fuel/oil heat exchanger. Some amount of suspended water is inevitable (and not considered contamination). What was unusual with the BA crash was the duration of very cold temperature coupled with the particular flight profile exposed a fuel system design issue that wasn't previously known. Post-crash investigation showed this issue was a general susceptibility of the RR fuel/oil heat exchanger design; the ice buildup had probably happened many times before on other aircraft (just not enough to block the fuel flow). Operating procedures were changed for the affected engines until the design fix could be implemented; the procedure change and design fix have nothing to do with fuel contamination.

Tom.

Topic: RE: Fuel Contamination At JNB
Username: EK413
Posted 2012-11-17 21:12:51 and read 1883 times.

Quoting tdscanuck (Reply 17):

Your right sorry my wrong... I do recall fuel contamination was seen as a possible contribution to the accident at one point of the investigation...

https://www.youtube.com/watch?v=KCTR4U9BHxw&feature=youtube_gdata_player

EK413

Topic: RE: Fuel Contamination At JNB
Username: HAWK21M
Posted 2012-11-20 03:21:28 and read 1878 times.

Quoting tb727 (Reply 4):
To protect from water at my company, we always test our fuel when the fueler pulls up to the aircraft but that's all we can check for is water

Shouldn't it be Contamination & water detection check.Out here its Pre , mid & post refuelling checked.

Topic: RE: Fuel Contamination At JNB
Username: nomadd22
Posted 2012-11-20 05:42:16 and read 1878 times.

I thought the BA crash was from water. Not from excess amounts but from an unexpected precipitation?? of water out of the fuel at low temps that caused ice to collect on the fuel line walls until the plane descended into warmer air where it all broke loose at once and clogged the heat exchanger input.

Topic: RE: Fuel Contamination At JNB
Username: tdscanuck
Posted 2012-11-20 09:22:05 and read 1878 times.

Quoting nomadd22 (Reply 20):
I thought the BA crash was from water. Not from excess amounts but from an unexpected precipitation??

It was from water, and not excess amounts. The precipitation wasn't unexpected (water will freeze out of the fuel at those temperatures) but it was unexpected that it would accumulate on the pipe walls, then all come off at once and overwhelm the fuel heat exchangers' ability to melt it.

Tom.


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