Guest TOSGcentral Posted December 16, 2007 Share Posted December 16, 2007 As the Accident & Incident forum is beginning to move into discussion areas as well as just notification that something has happened, I thought I would launch a topic that other pilots may care to give their views on. This may just be a false perception on my part, or it could be a product of different aircraft types now inhabiting RAAus – but I get the impression that we are having more aircraft catching fire after a crash, when once it seemed to be a rarity in the ultralight arena – even with very major damage. Do you feel that we are having more “Brew Ups†and if so then why do you think this is happening? Aye Tony Link to comment Share on other sites More sharing options...
facthunter Posted December 16, 2007 Share Posted December 16, 2007 Define situation. Tony, I personally don't have enough information to go on, but I believe you should seperate fires in-flight from post-impact occurrences. We probably carry more fuel than we used to on average.. Regards Nev Link to comment Share on other sites More sharing options...
Guest TOSGcentral Posted December 16, 2007 Share Posted December 16, 2007 Yeah Nev! Valid points (as usual from yourself). I was thinking more about the post impact burn outs. I do not think there have been many in flight fires – although there was speculation that the Rebel that went in at Boonah and two dead, may have already been on fire before it hit although the reasons for that crash are somewhat more complex. No – I am more interested in aircraft going in relatively hard (or comprehensively) then almost instantly burning out. Not much chance for occupants that may be trapped and injured but otherwise may have survived. There just seems to be a greater incidence of these nowadays so I thought it would be a useful discussion point on what, if anything has changed. Tony Link to comment Share on other sites More sharing options...
Guest browng Posted December 16, 2007 Share Posted December 16, 2007 Just a thought, but 'simple' ultralights like my old Sapphire were often pull-start, or hand swung. Maybe ultralight aircraft are more likely to have a decent size battery and complex electrical system than before, and are therefor more likely to have a source of ignition than they once were? Link to comment Share on other sites More sharing options...
facthunter Posted December 16, 2007 Share Posted December 16, 2007 Ignition source. Could well be, browng. A lot more metal parts (steel) could provide sparks too, on impact. Tony, are you leading to the type of fuel tanks that are on race-cars , that don't scatter fuel all over the place? I've been in plenty of aircraft that have 60+ litres of fuel behind me in nylon containers. Can't see that in any serious "G" event with the ground, that I wouldn't be in trouble. There's enough heat in a single litre of fuel to write you off .Nev... Link to comment Share on other sites More sharing options...
Guest browng Posted December 16, 2007 Share Posted December 16, 2007 I'm absolutely certain they would be less likely to catch fire if they had ADS-B though.. Link to comment Share on other sites More sharing options...
Guest TOSGcentral Posted December 16, 2007 Share Posted December 16, 2007 Naugh Nev - my thoughts are not leading any particular way and I had not thought about tank composition at all actually. As I kicked this off then really my own contribution (and it is a slim one which is why I wanted other views) is that after rather a lot of UACR inspections, a lot of the early ultralights were not fitted with master cocks - including the trainers. There is a possibility that that area is therefore missed in early emergency training and pilots (moving on to more sophisticated and burnable machines) may be missing a couple of key survival points - like get the master fuel cock off and the fuel pump off before arrival when you definitely know that you are going in! OK it is easy to quack and my actual experience in this area is limited to a single event. That was a total engine failure on climb out in a R582 T500 at 350'. There was actually no danger at all because I have pre-prepared defensive climb out and circuit patterns in place and I just stuck her into a paddock. But I assure you that in the landing I was flying just a glider! Everything was off and I had about 35 seconds to do it which is anyway a lot of time. But it could have been different if I had hit something in the grass, turned over, and we (my student and I) were on top of a red hot engine, still pumping fuel! Just some thooughts to possibly inspire input. Aye Tony Link to comment Share on other sites More sharing options...
Geoff Posted December 16, 2007 Share Posted December 16, 2007 You gonna get your bum smacked browng Link to comment Share on other sites More sharing options...
Guest High Plains Drifter Posted December 16, 2007 Share Posted December 16, 2007 Browng, at least if you had an ADSB, they could find your burnt out mortal frame a couple of hours earlyier HPD Link to comment Share on other sites More sharing options...
Wilfred Posted December 16, 2007 Share Posted December 16, 2007 Not sure if it applies as much to ultralights but statistically it seems that fires are caused by spontaneous combustion of insurance policies Link to comment Share on other sites More sharing options...
facthunter Posted December 17, 2007 Share Posted December 17, 2007 Fire source. Turtle, I was going to respond to you in similar light-hearted vein, but in respect to Tony I will get to the subject. In older large aircraft there was ,on top of the overhead panel, (where you would never accidently hit it) a thing called a "crash bar". In ONE operation, you opened ALL electrical circuits. It was called that because you hit it, (with your hand) when you were going to crash, to reduce the chance of fire. No fuel pumps, radio, battery power, lights etc. You might say the master switch does that. Well almost, but not as completely, and it's not as instinctive. Only ever used it once.... Nev... PS , Tony, there was a subaru powered aircraft that forced-landed some time back as a result of a engine fire, caused by carburettor flooding,( unfortunately fatally). To isolate the fuel supply would be an advantage, but from my recollection of research, engine oil catches on fire as easily and may be worse in some circumstances, so if the innards have come poking out the side, and the oil has gone on the exhaust pipe, you could have a problem . Regards Nev... Link to comment Share on other sites More sharing options...
Guest browng Posted December 17, 2007 Share Posted December 17, 2007 Another factor could be the increased use of MOGAS, with it's higher volatility. AVGAS is intentionally formulated for lower volatility to limit evaporation at altitude, it may be higher octane and release more energy when alight, but it's lower volatility makes it just a bit less likely to ignite in the first place. Link to comment Share on other sites More sharing options...
Guest High Plains Drifter Posted December 17, 2007 Share Posted December 17, 2007 Not an RAAus aircraft, though I have been hearing via other forums that the Cirrus is catching fire in many crashs - far more often then the old aloy types. I'm wondering if it has something to do with how these 'plastic' planes tend to fracture in a prang, as against an aluminum a/c deforming around the fuel tanks, though still holding the fuel. I'm not aware of any published numbers to compare the two structual types. Would probably have to dig though the accident reports. Probably a bladder tanked C182 (flexable fuel bladder within the aluminum wing structure) compared to the Cirrus may give some meaningfull answers. HPD Link to comment Share on other sites More sharing options...
facthunter Posted December 17, 2007 Share Posted December 17, 2007 Plastic. HPD. Might be more static electricity involved with composites too. A sheet metal aircraft is all at the one potential.. N.. Link to comment Share on other sites More sharing options...
Guest High Plains Drifter Posted December 17, 2007 Share Posted December 17, 2007 Nev, Good piont. Only just yesterday I was reading about the dangers of static electricity in flame retardent clothing - didnt even think of it re composite aircraft. HPD Link to comment Share on other sites More sharing options...
Guest ozzie Posted December 17, 2007 Share Posted December 17, 2007 Good thread. Interesting to know what really is causing the increase in fires. I can smell a govenment grant to study this(sic). On many of the early ultralight and minimums they usually came equipped with a plastic drum bungy tied on. In the prangs the drum departed company with the airframe, can't burn if it's not there. also made a good floatation device. later on with certification this was changed to fixed glass or alloy unbaffelled tanks. now they stay with the wreck and split or burst usually due to the fuel moving at great rates and is there is more chance of the fuel self igniting due to the heat generated on compression inside the tank. altho this is more of a diesel and crude oil thing. This is one of two main reasons that ocean going tankers press up tanks with sea water. Glass cracks, ali cracks. but a rubber bladder usually holds the contents well. I have a plastic tank on the lazair and i make sure i touch the airframe first when i remove it to refuel. By the way. i have yet to see a correctly designed fuel tank on an aircraft. If you are currently working on a project or rebuilding. consider this for your fuel tank. the fill neck tube should really go almost to the bottom of the tank. make the vent a reasonable size. this way as you are refueling the vapour laden air will vacate the tank via the vent and not into your face as you are peering in to see how much you got. If it does flash off via the nozzel cause you forgot to first touch it on your airframe (as a precaution to a broken earth strap ) the chance of losing both face and A/C are greatly reduced. Over the top again Ozzie Link to comment Share on other sites More sharing options...
Guest Baphomet Posted December 17, 2007 Share Posted December 17, 2007 During my time in the military, mostly spent in the chopper squadron in Townsville (Bell 47 and Kiowa) we were shown an incredible training film demonstrating the effectiveness of a fibrous 'sponge' filler used in the tanks on the Sioux. The material turned what was a bomb, into a (at worst) small localised fire. The material completely eliminated the explosive result usually seen with a ruptured tank. It is probably still available and would be worth considering. I think I may have heard of it being used by the drag racing fraternity. Link to comment Share on other sites More sharing options...
Guest High Plains Drifter Posted December 17, 2007 Share Posted December 17, 2007 Baphomet, do you recall the name of the material, sounds very interesting. HPD Link to comment Share on other sites More sharing options...
Guest Baphomet Posted December 17, 2007 Share Posted December 17, 2007 No, unfortunately I dont, it was several years ago and I was only aware of the military using it. I'll try a few contacts and do some searching, might turn something up. As I said I'm pretty sure a version of it was being used in drag/car racing. Like everything exotic, it will probably be hellishly dear. Link to comment Share on other sites More sharing options...
Methusala Posted December 18, 2007 Share Posted December 18, 2007 I think the material you refer to is a form of light gauge expanded al mesh. the theory is that heat from a fire is conducted away from the fire core and that combustion oxygen is hindered in access to the fire. Regards Don.(From memory called "Explosafe.) Link to comment Share on other sites More sharing options...
Galpin Posted December 18, 2007 Share Posted December 18, 2007 I recall reading about a product called "Explosafe" (spelling?) some years ago in the Kitplanes magazine. Whether this is still on the market I, as of yet, have not checked. Having a material like this would be good, especially in aircraft which have fuel in the fuselage, ala Jabiru LSA 55. Link to comment Share on other sites More sharing options...
Guest Flyer40 Posted December 18, 2007 Share Posted December 18, 2007 Foam filled fuel tanks have been around for a while in various motor sport categories, boats etc. I know some street cars that have them. I'm a bit surprised that foam isn't more widely used in aircraft, especially since it reduces sloshing which should help settle things down in turbulence. If you haven't heard of it before, here's an example of an off-the-shelf foam tank. http://www.sm-engineering.co.uk/alloy_fuel_tank.php Army-technology.com has a good summary on foam fuel tanks at; http://www.army-technology.com/contractors/protection/tss/ Great timing with this thread Tony, since I asked Garry Morgan last week if I'd be able to fit a custom-made alloy foam-filled tank to the Cheetah. Ozzie I'd be interested if you or others have any thoughts on how to prevent an alloy tank cracking due to airframe flexing. I'm wondering if rubber mounts would work? Mal Link to comment Share on other sites More sharing options...
Guest High Plains Drifter Posted December 18, 2007 Share Posted December 18, 2007 This is a very interesting thread. I've been looking into getting fire resistant clothing and helmet - in the Australian summer all very hot and debilitating to wear. It may be one of these fuel tank systems is a better idea. What do Boeing, etc put in their fuel tanks ? HPD Link to comment Share on other sites More sharing options...
Guest browng Posted December 19, 2007 Share Posted December 19, 2007 I'd be interested if you or others have any thoughts on how to prevent an alloy tank cracking due to airframe flexing. I'm wondering if rubber mounts would work?Mal If it helps, the J3 uses a felt pad about 1cm thick along the inside the mounting straps, and I have never heard of a J3 fuel tank cracking. This system was designed for the original steel tank, and is used unaltered for the later alloy tank which was introduced to save weight. George Link to comment Share on other sites More sharing options...
Guest Flyer40 Posted December 19, 2007 Share Posted December 19, 2007 This is a very interesting thread. I've been looking into getting fire resistant clothing and helmet - in the Australian summer all very hot and debilitating to wear. It may be one of these fuel tank systems is a better idea. What do Boeing, etc put in their fuel tanks ? HPD Boeings don't have anything in their tanks to deal with vapour, probably because they're too large. The explosion of TWA880 off Long Island was attributed to fuel vapour in an empty tank. In relation to fire resistant clothing, nomex would seem the natural choice. I think those green military flying suits you see around the place are nomex. And of course you could always go to a motor sport supplier. They have boots, suits, gloves, balaclavas and even underwear made from nomex. Mal Link to comment Share on other sites More sharing options...
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