Ayecapt

I went there to try and place a ad for a share in in our tecnam. Gave up trying the whole site seemed counter intuitive. Their rates were burried deep and i felt that the site was not being upfront with prospective customers. ( a bit like dealing with a telco) So i walked... Agree with the comments on RAAUS OUT SOURCING THIS SERVICE The marketplace is a barometer of the health of our sector, and RAAUS should run a web based members market as a service to its fee paying members and it will know if the sport is growing or shrinking just by monitoring prices and time taken to sell a AC .

Hi make sure that the main ground cable that connects your engine casing to the battery are all clean and tight. And the instrument panel is correctly earthed . Often when odd things happen electrically it is a poor earth. Earth conductor lugs must be bolted so that there is no paint under the lug face at all. We all know paint is a insulator but it also has some thickness . So any paint under a lug will stop good contact being made . Remember scratched paint is just ribs of plastic insulator under your lug. its very easy to believe that it will be right because that big bolt will scratch or gouge its way to make a good contact but at low voltages it cant be relied on to do so in the long term . And any voltage drop here is a large percentage of the battery voltage . I've had a tach where the entire internal mechanism ie the circuit boards and meter movement were working loose , that is the internal nuts holding it together were loosening. It of course was doing crazy things as the circuitry connected and disconnected. I got onto that one because i noticed that the dial seemed to be off horizontal. Sort of like it was rotating in its case which it actually was. However you have tried other tachos.

Hi all Engine has been re assembled , re installed , ground tested for around 30 minutes , carbs balanced etc. Heading out to the airfield this morning with the intention of further ground runs at run up revs. Then recheck all is well before take off. Out of all this on the positive side we have a engine that is as close to reconditioned as you can get when its got 1300 hrs on it. Some annoying oil leaks have been attended to , mainly the starter motor oil seal , 5 year rubber replacement is complete. And best of all there is no more brass in there ! Our L2 has done a great job on the overhaul . And i have learnt heaps about Rotax 912 engines in the process. I will post a photo of the 8 offending bushes after i string them together to add to the flying clubs Christmas decorations . Will be a reminder each year as they are hung up.

Im no chemist so cant comment on the zinc questions other than we had heaps of copper in the oil sample and high ish zinc but no reference to brass. And since brass ia a alloy of copper and zinc then it fair to say the brass was being de alloyed ( is there such a word) by the combustion process. Giving copper , and zinc in the oil and chunks of brass in the filter which didnt get melted in the cylinders all theory but it sort of fits. I am guessing that we will see highish copper for a while after rebuilding as the remaining brass is flushed out , but it will reduce. Our oil cooler was proffesionally flushed out and there was surprisingly little brass in the cleaning fluid afterwards. So maybe there is little brass left in there. Only time will tell. Cheers all lots of interesting comments . thanks

Quick update our heads have been stripped down valves lapped and reassembled ready for fitting soon. On the oil flow into the rocker area .....it does come up the push rod middle . Then it returns via the push rod outer tube . Oil must come in and back out. Otherwise it would heat and lose its properties with time. The brass of course is caught by the filter and the pre strainer in the oil return cannister. But it is being worn off these faulty rocker bushes , therefor it travels through the rest of the engine to get to the filter. The filter reduces the concentration of brass in the engine. There were signs of brass on the cylinder walls ! But it actually wasnt bonded to the wall . What i still cant come to terms with is that a brand new rotax rocker bush is very inexpensive , less than $10 yet someone made up brass ones .... Cant see any sense in that.

Its all in the charging system and the charging regulator. Lipos must have a charge controller either built in as in most laptop batteries or built in to the appliance. Thats where it all falls down . Guys using versions of these in rc cars charge them in a fireproof enclosure.! I dont feel inclined to ever use one in a AC. They are banned as airfreight now even the small button size rechargable ones used in some of our gps mapping devices . I have 45 years in electrotech engineering and these are the most dangerous batteries i have seen. Used correctly and in a tightly controlled charging environment they are fine, but if the charger malfunctions............not in the air not now at least maybe later as the protection systems improve.

Not one brass bush 8 brass bushes and 7 out of 8 have visible wear. We cant understand the mindset of the person who was responsible ( irresponsible might be better) but there ya go, i have theories on this but i cannot discuss them here. There might be some official investigtion , after all this is a maintenance incident that could have had serious consequences B.

The brass bushes should never ever have been maunufactured and installed ....the brass is too soft in this application. The plastic has a hardness greater than this brass. In effect this has probably saved this engine. Our lab tests of the oil showed copper , extreemly high, zink high and some lead which we can explain. ( av gas on occasions). But we have no steel or other metals related to case hardened bearings , cams or rocker shafts. We have no metals showing in lab report that relates to big end bearing metals. Or aluminium . So all thats been worn is brass. But the fine bits of brass will have entered the hyd lifters. There could be some in the oil galleries , and the oil cooler will have heaps , might need a new one but we have sent it to a company that specialises in internal cleaning of oil coolers ( usually in mining equipent ) they will catch what comes out at each cleaning cycle. We caught this problem early. Although the filter shows a lot of brass the one before showed just a trace so we immediatly saw the trend . The engine was actually running perfectly. Was not using abnormal amounts of oil A credit to its designers. The labs interpretation of the oil samples was invaluable . Yes prob do a 5 hour filter inspection , and send oil to the lab . Then decide on the oil change period when these results come back. On the oil flow the rockers are straight after the filter , so any brass went right through the engine but some did settle in the oil can . Cheers Brian

Hi all and thanks for the comments. The mods were we believe, ( being careful here ) authorised by a person outside the GA arena. And after registered in RAAUS. Doesnt make it less stupid. The lifters are being done for 2 reasons the first is that one was noted to be leaking and secondly the brass will have made its way into the lifters and might cause future issues. Thes brass entered the oil just after the filter exit so it has been carried just about everywhere. Cleaning the oil cooler of brass could be difficult . So the parts required might yet get bigger. We decided to get our local L2 to carry out the repairs . He is very experienced with the 912 series engines. If folks are interested i will do a weekly update ? Heres a photo of the swatch of oil filter showing the brass in it and one of the offending rocker bushes. Note its out of round .

Airmanship ,airmanship, and airmanship. No amount of parachutes, ipads radios or crystal ball replaces airmanship. The guy got the time wrong he has learnt we all have learnt from it . The organisers on the web page refer pilots to the web page flying programme in that programme the times are in local time but not labeled as such. Utc utc utc ,airmanship airmanship airmanship.

Thanks. Spent today with our L2 and got to bottom of the prob . Without going and pointing fingers..... A previous owner performed a top end overhaul of the engine. Rings valves and rocker bushes. They replaced the rocker bushes with brass not bronze and NOT the rotax plastic ones that should have been fitted. Result was 7 out of 8 bushes are worn to a oval shape. And they were binding as the valves were lifting . Most tight at top dead centre. So it will be quite a parts bill , bushes , rocker shafts , new lifters because there will be brass in them and possibly rings due to brass in the oil . you can see a brassy tinge in the cylinder walls. Thanks Brian

Hi yes a 912s engine ( ex ga) the engine is tight at top dead centre ( tdc ) and bottom dead centre ( bdc ) with the plugs out and gearbox removed. There is also very high copper showing up in the oil filter and in the oil sample analysis. Doing a crank angle test today . But was wondering if anyone has heard of this fault before. It seems Rotax hasnt . Remarkably the engine was / is performing well starts first kick developing smooth reliable power . Oil , coolant temps normal , oil pressure normal . No rattles or odd noises at all. Just the tightness and the copper. Engine TTSN is 1300 hrs . Gearbox has 200 hrs TTSO and basic tests are ok . It could be that the copper and tightness are 2 separate issues and not related. Of course its grounded till we find the cause.

I also was at GEFI . The pilot concerned did attempt to arrive at a quiet time in the event. Early afternoon. And at a time when the flying displays where not happening. However DST AND EST got confused. Which highlights the need to use UTC FOR ALL THINGS. aviation. I think the notes to pilots might have been in DST i cant recall. But it usually takes two things to create a incident.

I used a 16 gig mini prior to my 64 gig unit. And had no probs . So dont hesitate if thars whT the budget dictates. I just love the freedom of having every map , document or what ever else all in one machine. So the 16 is fine just regulate what you carry on it . At my ripe age i just wanna keep it all together easier to find during seniors moments , lol. Brian

Power banks. Yep watch for this sort of thing with any power adapter. Adapters operate as switch mode power supplies, which means the have inbuilt oscillators . These oscillators are supposed to be "clean" but many produce harmonics that get into the radio receiver. My ipad car adapter a non genuine one wipes out the fm band if the station is a bit weak . It just mutes the audio , just like there was nothing there at all. Our vhf Ac radios are just above the fm band so are good candidates for this new feature of our modern world.

I am onto my second mini, no issues with rhe size. Use it for a efb and a checklist provider. Latest one is 64gig so i have no probs with storing everything i think i might need . I use a ram mount onto the lower left side of the windshield. ( Tecnam Sierra ) These mounts are not cheap but dont come off unless you want it off and can adjust to any angle etc and lastly my eyes are getting old but its still not a issue on the mini.

Stalls on final or the turn onto final. In these incidents I guess the airspeed was too low for the angle of bank and perhaps pilots were dragging the aircraft in because they were too low to start with? So they want to be at their approach speed but also want to at least to slow the decent. Power is applied but a nose high attitude is maintained or even increased then they are behind the power curve. In summary the pilot is trying to salvage a lousy approach. The question to me is why not go around, apply full power , lower the nose , regain speed and then height. The need to land is a compelling force in our brain . We seem able to go around if we muck up the round out and flare but do not seem able to make early decisions to go around when the approach is lousy. If it dont feel right then it aint right. This can include too high, too low, too fast and too slow. The term "I am attempting a landing " should be used more (at least in your own mind ) and go arounds should be seen as a sign of a quality decision making by the pilot . Not a sign of a bad pilot . Oh and thanks for welcome to the forum ...cheers. Brian

Hi fairly new here but i have been pondering why it seems to me that some very senior pilots get into situations that lead to a serious incident. And yet on the roads it appears that its the young drivers that are at risk . I dont believe its anything to do with the quality of formal training . I can remember the moment i went solo on my bike. Like in the video somthing just clicked. Likewise the landing flare and touchdown , it took forever but it clicked one day. So i believe that senior pilots haven't unlearnt anything its all clicked in. Maybe they attempt to perform flying tasks that bring more satisfaction. It is the basis of human factors that we are trying to get a handle on. I remember when i started out I wanted to be as far away from the ground as i could. The ground was the enemy. Now i notice i am happy enough to drop down for a better look at that island etc. i am starting to think that flying hours vs safety will cross at some point, what is the result of being behind that curve? More research is needed. Thanks Brian

I took quite a number of hours to solo because i was overthinking the landing flare. Perhaps if someone feels low confidence , its simply that they are thinking about the possible things that go wrong, rather than the things that wont. Why wont they go wrong? PPPPP . Proper Planning Prevents Poor Performanc, and that builds confidence that you ar in control. You are flying the aeroplane its not flying you. Bad bumps...... Do somthing to improve it . Climb decend or slow down. But make the decision and do it. Cheers