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Jet A1 contamination?

Old 9th Oct 2016, 20:20
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Jet A1 contamination?

Good evening all

First of all, apologies for joining the forum then immediately asking a question but need to avail myself of the wealth of experience found herein.

I need some advice on when to consider a bulk storage tank of Jet A1 as too far contaminated and condemned .

To explain, i manage a fleet of super-yachts and one of the yachts in particular has its own helicopter which forms an integral part of the yachts operation. The helicopter is based semi-permanently on the vessel. To allow this, the yacht is fitted with bulk Jet A1 storage tanks to allow full re-fueling capabilities.

All was fine until a few weeks ago when it was notices that during regular sampling of the fuel in the tanks, several small pieces of rubber (approx half the size of a penny) were found in the sample taken from the tanks foot valves.
The source of the debris was found to be some gaskets of non-compatible material fitted in the discharge pipework going up to the on deck fueling nozzle.
The suspect gasket were degrading and breaking up allowing small pieces of rubber to head back into the tank. (total of about 20 small pieces found in the tank)
These are currently being replaced for the correct Viton rubber material but the question i have is this:
Should the 8400ltrs of Jet A1 in the tanks be condemned or is it safe to flush out the remaining debris through the sample/foot valves then rely on the 0.5 micron coelescer/filters as fitted to the discharge line. All fuel pumped up to the airframe has to pass through these filters.

For info previous fuel samples taken at the nozzle and sent for testing revealed no issues and the fuel is clear and bright with no traces of water.

Any advice would be appreciated.

Kind regards

Simon
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Old 10th Oct 2016, 06:33
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7 tons of Jet A for the chopper, man that must be one fancy boat!
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Old 10th Oct 2016, 07:31
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I know very little about bulk storage, but I will just say that we tend to have a zero tolerance when it comes to fuel. I was once involved with contaminated fuel on an A330. We had filled the wings and as a result of water drain checks showing serious water/gladis in the samples we ended up draining the lot and starting again. About 70 Tonne!
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Old 10th Oct 2016, 11:51
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Contact the fuel supplier for help, keep samples of the debris. If it's not dissolving in the fuel it should be filterable. Might need to be pumped out tanks cleaned and the fuel filtered back into the tanks.
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Old 10th Oct 2016, 18:29
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Thanks everyone.

The rubber particles have not dissolved and are the larger bits are easily removed through draining the tank by way of the lower sample/drain valve.

As an engineer I'm confident that the 0.5 micron filters will keep the fuel at the nozzle contaminant free but our outside helicopter management company issued an incident report condemning the fuel imediately.. Frustrating as the bulk tanks were only just filled up from near empty two weeks ago at a cost is 22k.
I think In cases like this it's probably best to err on the side of safety and, based on the fact that an incident report has been issued, it's pretty much been taken out out of my hands...
Anyone need 8000ltrs of Jet A1?

Thanks again for the advice, great to draw on such a broad spectrum of experience...
Kind regards
Simon
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Old 13th Oct 2016, 18:26
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As a one-time accountable manager for an airport including Jet A1 and AVGAS storage and delivery, permit me to make two points;

The fuel leaving the tank on its way into an aircraft tank must be totally free of any contamination. In other words, any filtration between the storage/delivery vehicle is there to remove any contamination that you do not know about, and is not to be used to remove contamination you know is there.

Perhaps teaching Granny to suck eggs.......when you have a contaminated tank and need to empty it and then clean it, before returning the fuel to it after it has been filtered, probably both on the way out and back again, the problem is usually having an empty contamination free tank of the same size to put it in!
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Old 13th Oct 2016, 22:41
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If you are going to throw the fuel away, offer it to a local farmer, should keep his tractor running for a while.
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Old 14th Oct 2016, 00:43
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Don't do that in the UK. If it's used for heating or vehicles the inland revenue are entitled to get the fuel duty from you!! And yes it has happened, with the operator being threatened with court action and they were giving it to the farmer for heating greenhouses.
It may be scrap to you but it is fuel to the revenue unless you get a waste disposal firm to take it away lawfully.
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Old 14th Oct 2016, 17:46
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If you do have to bin it, a museum where they run old jets will bite your arm off for it.
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Old 14th Oct 2016, 22:00
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I'm just asking a stupid question here, what does the yacht run on? Coal?
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Old 15th Oct 2016, 12:30
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piperpa46 - The electronically-controlled, common rail diesel engines of today - be they marine, automotive or industrial - are pretty finicky on what they require by way of fuel.

The older diesels would run quite happily on Jet-A1 - but todays electronic models have sensors measuring fuel viscosity, and possibly even lubricity - and any fuel entering the fuel system, that is outside the strict fuel parameters set in the engine ECU by the manufacturer, would quite likely result in engine shutdown, or an ECU reset to "limp-home" mode - resulting is severe curtailment of engine RPM's and power output.

The cetane rating of Jet A1 is not measured, nor fixed, and its cetane number can vary widely - unlike diesel fuel, which is refined to a different ASTM standard (D975), and which has a defined and fairly narrow cetane rating range.

Finally - common rail fuel injection systems operate at extremely high pressures, with clearances between the moving parts of high pressure pumps and fuel injectors, running at half the clearances of the older diesel engine (which already had clearances as low as 0.0001" or 0.00254mm).

These exceptionally close tolerances and extremely high pressures require a diesel fuel with a high level of lubricity, to ensure those close-fitting fuel injection components don't seize or gall.
Jet A1 is not likely to have the same lubricity as current-specification diesel fuels, and if any particular CR diesel engine does not have fuel lubricity sensing engineered into the design, it will suffer high pressure fuel pump and injector damage, as a result of using Jet A1, instead of the specified diesel fuel.
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Old 17th Oct 2016, 19:27
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Hi Anchor.....I was lucky enough to take an IFQP auditor course recently. Capot has it bang on. Any contamination is cause for rejection whether you know the cause or not. You can't guarantee some of the material did not dissolve in the fuel.
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Old 25th Oct 2016, 01:37
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Considering the aircraft is flying over water, I think you probably feel a little gratitude that it was taken out of your hands eh?
As for the farmer, hasn't revenue already been paid on this? I thought the old red diesel was due to them paying less than a road user. Do farmers tanks get dipped?
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Old 25th Oct 2016, 17:02
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It should also be pointed out that 22,000 euro for 8000 litres of A1 is very expensive.

At the moment it should be possible to get it for around 0.70 euro/litre....ie 5600 euro for 8000 litres (or maybe even less).
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Old 9th Nov 2016, 07:55
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At the moment it should be possible to get it for around 0.70 euro/litre....ie 5600 euro for 8000 litres (or maybe even less).
Not necessarily. If its (for example, an EC135) sat on a yacht then its generally non commercial operations so higher taxes. Fuel taxes as you are aware vary by country and it depends upon where the vessel was bunkered as to the VAT and MOT eligible.

A lot of helo's sat on superyachts are obviously private operators even although the aircraft may be under management by an AOC holder, the operator cannot claim tax free in many cases as it is a private flight. These days, many of them are M-registered meaning private flights only. Where I'm based, private flights pay around 45 cents more than commercial flights per litre.

The fuel supplier is also transporting bulk fuel to the yacht in a bowser, adding to the cost.
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Old 9th Nov 2016, 11:46
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I would suggest draining the fuel tank and return fuel to supplier for a credit note. Safest option would be to run it through their system
The fuel tank should be cleaned and checked internally as well.
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Old 10th Nov 2016, 16:48
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IF you've had one gasket affected by the fuel you'd be well advised to go through the rest of the system and verify there are no more. If someone's specified or supplied one gasket in the wrong material there may well be more.

If it does prove disintegration and no sign of dissolving I'd have no hesitation in using the fuel once it has been suitably filtered as there is no reason not to; standard aircraft-spec fuel filters are more than able to achieve that.

As said above, you'll need a suitably clean vessel large enough to hold it all while the tank and system is cleaned out. Eight or nine of those metal framed metre-cube iso-tanks is just the thing and can't be too costly - probably good as a throw-away afterwards solution. You'll need a transfer system with an inline filter to get it all back into your main tank afterwards of course, and a decent spillage on deck would probably cost you more in harbour clean-up fees that just scrapping the lot.

Frankly by the time you'd set all this up it might just be cheaper and quicker to scrap the fuel and pay the disposal costs. I imagine an operation like yours can easily afford that.

Last edited by noflynomore; 10th Nov 2016 at 17:01.
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Old 10th Nov 2016, 18:26
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Hi,

I'm working on tankers transporting A1 around. A1 has one of the highest specs and can be a total nightmare when the ship has previously transported another clean product around due to the level of cleaning required in the ships tanks to make sure it is not contaminated.

But it has to be remembered where this is being used and the importance to delivering on spec cargo to terminals.

First of all, you've noticed you have contaminated cargo so you have a contaminated tank. if you decided to jettison everything in that tank you're going to have to go tank diving to verify it's clean before you put anything else in there.

You can't rely on strainers to do the job because they'll either become blocked when you reach the bottom of the tank or if these particles are suspended when pumping at high rates you'll have a good chance you'll just break through the strainer if these particles are large.

Strainers are rated for the pump suitable for that tank and these will vastly be different to a fuel filter on an aircraft if it manages to pass through your filters.

You've got off spec fuel now, all you can do as a responsible ship operator is get rid of it ashore. Clean the tanks thoroughly and replace the filters on your pumps.

Expensive problem caused by a more common problem than you would imagine in the shipping world. Save your reputation for a few thousand dollars rather than your owners chopper ditching because of the mistake.
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Old 12th Nov 2016, 20:38
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Not necessarily. If its (for example, an EC135) sat on a yacht then its generally non commercial operations so higher taxes. Fuel taxes as you are aware vary by country and it depends upon where the vessel was bunkered as to the VAT and MOT eligible.
Good point. However even taking all that into account I think 22,000 euro is a bit on the expensive side for 8000 litres of A1 (2.75 euro/litre).
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Old 15th Nov 2016, 04:36
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Here's a world jet fuel specification document from ExxonMobil. There are several specs for Jet A-1 that list particulate contaminant limits.

http://www.exxonmobilaviation.com/Av...ations2005.pdf
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