Bluey

Crossing an active runway the way they did is plain dumb in my opinion. Just asking for trouble. The pilots of these large choppers (and smaller ones) while they do a magnificent job need to be aware of the risks of operating at small airfields where light aircraft are the norm. Landing or taxing or taking off near a parked aircraft can easily cause an aircraft to be flipped and possibly written off. Lucky that cesna was tied down. I wonder if they even bothered to check that it was secured before they landed. I once saw a trike flipped by a rescue chopper while it taxied prior to take off. Luckily the pilot was un injured. Bluey

5.7.2 clearly states these aircraft need to give priority to other traffic. 5.7.2 Aerial application (agricultural) aircraft are permitted to conduct aerial application operations which involves low level maneouvering after take-off and prior to landing. These low level maneouvres are not required to conform to the standard traffic circuit. However, pilots of other aircraft can expect aerial application (agricultural) aircraft to:  maintain a listening watch and broadcast their intentions on the CTAF; and  give priority to other traffic.

Very sad. The council grounded all ultralight activity out of the aerodrome due to water bombing aircraft movements.

I saw a few of those doing circuits out of Albion park the other day. I wonder if it was one of those?

I might have to start doing that too. Already shave the head.

It occurred after about 5 litres of fuel was pumped into the tank via a mr funnel. It could have been the result of a spark occurring when the nozzle got close enough to the funnel for a spark to occur. I can't recall if the nozzle touched the funnel before the spark. During fuelling the nozzle never rests on the funnel as this would cause my funnel to tip and spill fuel

No, I was wearing a pair of shorts and a t shirt. The t shirt was cotton and polyester blend. I do recall the drum brushing up against my leg as I walked it the five metres or so to the trike. I then put it down, open the cap, installed the nozzle and started fuelling.

I think the following procedure might work well: Bond or earth funnel to trike, Earth trike, Wipe drum with damp cloth including nozzle. This will make the drum conductive and allow it to be effectively connected to an earth. Charges built up in the flowing fuel should be the only possible ignition source but given the relatively low flow rates from a drum it shouldn't build quickly as at least some of it will dissipate when the fuel makes contact with the funnel. Not using the funnel would make the fuel charging issue less as a spark inside the tank would be much less dangerous than one inside the tank. This is because the fuel air mixture is too rich (unless the tank is empty) to cause ignition. Those who don't use a funnel will probably have less risk of fire but greater risk of fuel contaminants being an issue. I know of some people who never use one and routinely fill up with mogas. I wouldn't ever dispense with a funnel personally.

I just found this good article worth reading. Here's the link: http://www.ccohs.ca/oshanswers/prevention/flammable_static.html Bluey.

It's easy to get this whole thing way out of proportion especially by me right now. As Maj has stated it is a very rare occurrence. Airborne have stated that they take no special precautions when fueling trikes and they've been around for decades and have flown many thousands of hours and refueled thousands of times without incident. The whole triking community would have probably accumulated somewhere in the order of a million hours in the decades of operation and most have refueled as I have. In all, I count about 4 known incidents in that time including mine. Let's say another dozen exist that have not been reported and you have less 20 tops in the history of australian triking. That's 20 failures in at least hundreds of thousands of refueling events. Clearly, a whole range of events have to come together to cause a fire. Yesterday was one of those rare days when it all did.

I Was wearing flip flops but that doesn't matter as the contact between the two items is what causes the charge build up in both. When contact was made the charge did not dissipate. A properly earthed item would remove charge from my body and not charge it as was observed as the two come into contact, something we all experience regularly in our day to day lives. I did a less controlled experiment at the airport earlier today where I charged the drum on myself and then a friend also tested it on themselves. Same results. Also, the movement of electrons depends on which item has a stronger tendency to attract electrons. Therefore, the exchange of charges can vary with the type of materials in contact. Sometimes an item may attain a positive charge and at others a negative.

I had no trouble inducing a charge with the container on the ground. Remember, I used a red drum. It would be interesting to test the earthing properties of the black ones.

I just tried it and it worked perfectly. I first showed that a charge could be induced on the drum using hair as before (no earthing). After I was satisfied that the drum indeed could be charged I then wiped the surface of the drum using a lightly damp cloth. Charging by the same method as before failed to induce any charge what so ever! Just be sure to wipe the surface of the nozzle too if you use one.

That is a top idea head in the clouds. The evaporating moisture will remove charge just as would happen on days of high humidity.

Charges that build up on metal items distribute themselves evenly over the surface of the conductor and are easily removed by earthing. Unfortunately non conductors do not behave in the same way. When they become charged the charges cannot easily move around on the item as they are non conductive (this of course is dependent on voltage as anything can become conductive if the voltage is large enough even plastic). I just did a quick experiment to confirm this as the humidity today is lower than yesterday ~10%. I attached a set of jumper leads to the same drum I used yesterday and earthed it to my homes earth stake. I then used the hairs on my legs to charge the side of the drum by moving the drum back and forth along the hair. I had no trouble doing this with the drum attached to the earth. I know it was charged by the large deflection of the hairs on my legs as the drum was moved toward them (so I used the hair to both charge and detect that charge). I also then used my finger tips to produce tiny audible sparks as I moved them close to and made contact with the drum. I then attempted to discharge the drum by rubbing the palm of my hand over the surface of the charged area. The charge reduced but was not eliminated. I repeated the above procedure with and without the earth leads connected with no significant differences in the results. This demonstrated that the earth was not effective. See the attached image for my setup. Now assuming that the earth I used was a valid earth as I would expect it to be, then the following conclusion can be safely made. Conclusion: Earthing plastic fuel drums is ineffective. So, the results seem to suggest that static build up on plastic drums during low humidity is common and difficult to discharge. What I don't know is at what humidity level does it become a serious issue? What I mean by this is at what point will a large enough charge occur that a spark is likely? And if so, how big does the spark have to be to cause a fire? What I can confidently say is the spark I heard yesterday was louder and bigger than any spark I deliberately created today.

I have to agree with what's been regarding earthing the aircraft and the can. There is no point earthing the aircraft without the can as sparks will always be generated from a charged object coming into contact with earth. The problem may be exacerbated by the plastic containers as they cannot be effectively earthed. The fuel itself is another problem as it will develop a charge when it flows. It cannot be effectively earthed as it is non conductive too. There is no way to eliminate the risk completely except to not fuel when humidity levels are very low. Yesterday's humid bottomed out at 27% which coincided with the time I was refuelling. My advice is to check humidity levels at your airfield via the BOM site and avoid refuelling from cans when humidity drops below 40% or so. If your not at an airfield with observations, pick the closest area to you with observations as humidity levels can be dramatically different over short distances. Alternatively, if you are detected static discharges on yourself or objects near you then you know it is a danger period for working with fuels. After the decision is made a fire extinguisher at hand should be mandatory from now on.

I just remembered some work I did on this very subject many years ago and from memory the results showed that the correct fuel air mixture was reached when there was pretty much no fuel at all left in the tank. At anything more than this you just get burning of vapours at the mouth of the container. However, if the burning is allowed to continue unabated, you eventually get the magic ratio and then suddenly it goes bang!

Are you sure about that Kaz? The drum had a nozzle on it and the trikes fuel tank was without lid. It seems to me that the vapours inside the tanks expelled much of the air needed for combustion in this case. It took as much as 90 seconds to extinguish the flames. Hard to say for sure how long it was as perception of time is really stretched in such stressful situations.

Thanks, it's amazing how hard it is to find a fire extinguisher when you really need one. Our trike hangars are chock full and I couldn't find one today when under pressure. I was standing no more than 5 metre from one but it was behind something so I missed it. It's critical to not only know where they are but to make sure they are in obvious places and in plain site under normal circumstances. You should be able to easily see it every time you walk into the hangar. This one is out of the way. You don't realise how important this is until something like this happens.

Yes, it's the black one. I'll be earthing it and the trike body from now on. Does anyone know of other instances where this has occurred? Bluey.

While refuelling the trike today, a fire started when a spark jumped from the tip of the nozzle on my fuel drum to my mr funnel. The fire was contained mostly within the funnel with a small fuel spillage around the funnel. The tip of the nozzle was also on fire and when I dropped the drum a few metres from the trike, it tipped spilling a small volume of fuel which also burnt. A fire extinguisher eventually put the flames out. A very scary experience. What saved me was that there wasn't much fuel in the drum thus preventing any significant splashing when the drum was dropped. Having said that though, we've all filled up in similar conditions in the past without a problem. In fact I spoke to a number of trike pilots who said they experienced no issues today. The conditions today were ideal for static charge build up. The drum was a plastic one and no earthing has ever been used at this airfield by trike pilots to date. Airborne doesn't think earthing is necessary. In fact, they aren't sure it increases safety. There have been only two other instances of a refuelling fire before my example and only one that airborne was aware of in the history of airborne trikes. I think earthing is a must and I'll be taking this precaution from now on. Also, I'll be having a fire extinguisher at hand whenever one is available. I will consider getting one for the trike if possible and will definitely be carrying a fire blanket from now on. Bluey.

I did the fuel tank replacement with a friend today and it took about 2 hours. It could be done on your own quite easily. On closer inspection of the old tank, it's quite obvious from the staining that the slow leak has existed for some time, possibly before I took delivery of the trike. I would always take a look at the fuel level at the end of each days flying. Sometimes I would notice that it was slightly lower by a few litres after a week or so. I always thought it was a little odd but never took much notice as I assumed I'd simply forgotten the true level or that I'd incorrectly measured it in the first place. Or, that I'd lost a little due to evaporation. The point is: always investigate when you get that nagging feeling something doesn't quite seem right. Bluey.

First thing I did when I got home last night is generate a defect notice through the HGFA website and SMS one of the owners at airborne. They replied pretty quickly and are now aware of the problem. It looks as though a replacement is the only solution. This will mean probably shipping the trike back to the factory. As this is the second instance of a an identical fault, it could be a bad batch of tanks in which case all owners of similar vintage will need to do immediate inspections. Bluey.

I've got an XT912, 2009 model and I detected a slight fuel leak by accident today. Not sure how long its been there for since no drips have ever been noticed. I only detected it because I needed to replace my starter battery today. While in the process of removing the battery, I noticed a slightly damp area just above the battery. This turned out to be fuel! When I moved the seatbelt strap I saw the crack. It's about 10cm long and sits above the 45litre mark in the tank. This is the second crack detected in a trike fuel tank at YWOL in the last few months. The last one was on a two year old trike with only 29hrs. Mine has 692hrs but is 4 years old and I don't know how long the leak has been there. At the time it was detected I had 65 litre of fuel in it (just filled it). Bluey