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justincarter

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    D-EKNA
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    M20F

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  1. The mechanics taking a look today. For interest - Ill let you know what he finds. 100% that the painters aren't very mechanically minded! Two wires going to the tail light with push to fit unions in the lower right inspection panel appeared to have the live feed direct to earth with a large current draw. When reversed there is a low draw and the lights work. But i see your point that if both cables are live and neutral is just ground, can't see why that would make a difference (bulb doesn't care which way its wired!). Well take a good look for cable damage in the tail incase we've just nudged something live off an earthing point somewhere. Thanks for the other tips!
  2. these seem to be in stock http://www.aircraftspruce.com/catalog/inpages/umaAmmetershunt.php?clickkey=14951 Sadly, engine monitor upgrade would probably be a paperwork nightmare in EASA-land. At the moment, I just want to get flying again!
  3. i see form the sticker on it that the JPI unit is a 100A shunt. Can you see from the J wiring diagram if the original is also a 100A unit or 60Amp? I think (looking at the F wiring diagram- link above) that the one I have should be a 60A unit I don't know if it would make much difference. Other than perhaps providing a little less protection in overload or ?? making the (crappy) ammeter over or under read a bit
  4. Fingers crossed that someone will have one they can let go
  5. Its a fair point about the fixing to the firewall. On Installation, one nut and bolt goes one way (forwards through the firewall) and the other goes the other way. It seems unlikely they moved any of the fixings to cause a shunt but can't rule anything out. That said, the picture 'flattens the appearance' a bit, i.e. the nut is a decent distance from the shunt in the plane into the picture ( whilst appearing to be practically touching the shunt in the plane across the picture. I pulled the boots back for the picture. Well here's what we did so far... Looked for obvious burns to the fabric in the local area / scorched cables- couldnt see any. Pulled all the breakers on the panel. Used a 60amp inline ammeter across the poles of the shunt. One by one, I closed the breakers while observing the current flow - ready to cut the power immediately there was a big draw. With each panel item, I saw an appropriate current draw, so I'd pull the breaker and move onto the next. Fuel pump, beacon, strobes etc. Then got to the nav lights. Remember, in this 67F, the breakers on the Left bus are the throw switch type (whatever the posh name for that is). As soon as the nav lights were on -immediate 30+amp draw. I don't know whether, had if I left it on, if the breaker would have 'popped' or not as I switched the nav lights off immediately. So there seemed to be a short on that circuit. We then removed and inspected the three nav lights (one on each wing and third on the tail) and found that the high draw was associated with the tail light and were suspicious that on re-installation of the tail/ rudder assembly, the wires were reversed in polarity. Once these were swapped, all three nav lights worked with a 2A draw, as did all the other electrics. What I don't get is, that for this tail light polarity switch to have fried that shunt, the Nav light Breaker must not have opened in overload. i.e. it would have to be suspect. So another explanation is that something else fried the shunt during the works, and We just happen to have found another error coincidentally, without the fault we found having caused the shunt to fry. Its hard to imagine the wiring/bus bar/ breaker for the Nav light setup begin able to carry enough current to fry the shunt without being fried themselves. Does anyone know where to source the modern day equivalent of a garwin 22-370-60 shunt (which is whats listed on the wiring diagram for the aircraft). I saw some RC Allen shunts which look similar on the A/C Spruce website like this.. http://www.aircraftspruce.com/catalog/inpages/rcallenshunts.php?clickkey=14951 but oddly they're all out of stock. So not sure what to go for next. And Ill need to have is shipped to the UK and we might still not have found the actual cause of the problem!!
  6. I tried to collect my '67F from bare metal respray yesterday. I flew the aircraft into the paint shop a couple of months ago in working order. After I dropped it off , they have had it running to taxi it. Obviously, during the respray the tail has been off, nav lights, cowls, everything- and then all put back together. It has been stripped and water sprayed and then repainted- the works. Its had an engineering sign off for all the flight control work. The paintshop folks handed over the aircraft keys, with a few items left to tidy up and commented that the battery is flat and needs charging. I thought that a bit odd after those weeks on the ground (unless something had been left on). I set about doing the most major preflight check I've ever done with the aircraft tucked away in the back of a hangar. When checking the electrics, Sat in the P1 seat, upon switching the master on, I could hear the main solenoid in the rear click but I had no power to any nav lights, radios, panel items -nothing. I didn't try to turn the engine (a/c in the back of hangar). I got a handheld voltmeter and checked.. across the battery -14v or therabouts across master solenoid - 14v or therabouts on the firewall at the starter solenoid - 14v or therabouts I followed the high current cable from there, along the front of the firewall, through the R side of the firewall into the avionics bay, and then across the ammeter shunt to find a huge volt drop across it and on inspection the shunt is burnt out. You can see the shunt in the attached wiring diagram. Its a big baby. I guess it must have taken quite a load to burn that out. It'll need a new one like this... http://www.sigmatek.com/pages/prod_description/PD_ACC_shunt.html So my Qs... Any thoughts on what might have caused it? Ill be needing to get a mechanic to look at it but any preliminary thoughts on how to trouble shoot from here? The output from this shunt feeds i) the main bus bars in the panel and ii) the Volt regulator and generator/alternator. Checking i) I suppose is easy enough - pull all the panel breakers, re-make the burnt connection then engage all the beakers one by one until one goes pop. But my amateur money is more on ii)- a Volt regulator / alternator issue. Of course I am interested in how this happened. I suppose it wasn't like this when I flew it in there -but my main aim is to safely troubleshoot, fix and get it out of there!! Any thoughts or tips /advice would help! Mooney M20 Series Maintenance Manual M20F WIRING DIAGRAM.pdf
  7. Thanks folks! Clarence, Yes -2 inspector sign offs needed. Hopefully that means something. The worry is one or both are a passing signature without doing due diligence on the aircraft. Perhaps unfair - but its a pretty closed door process so who know what goes on ! good to hear from you Ben, Ive had D-EKNA for about 6 years. Bought it from Michael Hermann who moved to NYC back then. She's been a great steed. Thanks for the tip - Ive digested CAP747. All good advice. She's being painted at a newish shop near me 'RS paintworks' where 'NA was (until recently) based (Fishburn airfield in NE England). Theres much to tell about the process so far (I'm mid way through writing an article for the PPLIR mag about it) but perhaps give me a ring when you get nearer the time for the final 'low-down' Justin
  8. Thats great guys thanks! Cliffy, what do control surface balance checks look like? - the max and min deflection forces to move any given surface up or down (or side to side)? Basically whats the minimum i should expect? Nice point about the empennage checks - so its horizontal stabiliser tips fore and aft to check the empennage mounting (i.e. one axis) and bottom of the vertical stabiliser up and down for the other axis (jackscrew play). I wasn't planning to pay the final instalment until Ive flown it and there aren't any remaining issues. Ill see if I can get my A+P to check it too. (though He's 150 miles away) yes hopefully it'll be pictures galore in a week or so! justin
  9. I will hopefully be picking up my '67 F from bare metal re-spray in the next week or two. Obviously I'll give her a thorough looking over before accepting her back, jumping in and flying away. I'm pretty sure the logs / paperwork will all be in order (including double engineering sign-off) but, mindful that all of the control surfaces have been off (including the entire empennage), what kind of checklist of things would you, as a receiving owner, check before flying away? Comments about the respray itself or the control surfaces checks welcome!! Im just psyching myself up for the big day!! I will of course post pics when she's back home!!
  10. Thanks Cliffy, I guess living in Arizona means you're 90% of the way there. The dank NE Coast of England is another story Justin
  11. thanks guys, Carl the Prekote looks interesting. even if the prekote or alodine just gets used on the 'high erosion areas' and where there was corrosion before the primer might be a start. it seems to reduce corrosion be getting great adhesion of the primer to the metal surface. Any thoughts about the fixings for the inspection panels once all is done? stainless or otherwise or other strategies ?
  12. yes - planning to strip the whole aircraft. Thanks for the zinc chromate tip.
  13. Wise Mooney folks, Its time for a respray on my 1967F. Its looking a little tired and we look like were destined to be together for the foreseeable future! One of the reasons is that along the underside of each wing, where the (many!) inspection panels are, stainless screws were used and these have caused a little metal on metal corrosion to start. It starts around the screw holes in the skin. The engineers have inspected and its only superficial. I attached a picture to illustrate the point. When it comes to the re-spray, at some point we'll have a bare metal aircraft. What should be done with this corrosion then? I guess mechanically remove (wire brushing, sanding etc - being careful not to remove too much of the outer metal layer) but then what? - once corrosion free - direct to etch primer, primer and repaint - OR should we be looking at some metal treatment or other to reduce the risk of return? And after the respray- any thoughts on stainless or CAD plated screws or any other tips on reducing risk of recurrence? The holes are countersunk so no chance of a plastic washer really. In the second picture, you can see the original screws around the windows (They were painted over at last respray). Around some of them you can see the slight yellow / orange stain of rust - I guess from the screws themselves - Im presuming these will all need to come out, holes treated and screw replaced before respray otherwise well have corrosion underneath the new paint from the outset? (Once all is done Im planning an ACF50/corrosion X strategy)
  14. Thanks Guys - thats very helpful. Can't find it in the (German) maint logs Ill start with a check to see if there is a joint behind the radio stack to see if switching will give the answer then ill take the forward most antenna, try the foil wrap and handheld trick on that one and failing that - the signal tracer looks a great idea! what a resource this forum is ! thanks all. Justin
  15. Dim question here folks. Ive a GNS340 and KX155 in my '67 F. The reception (and transmission) on the 430 has been getting steadily worse. The two comm antennae are in different locations on the fuselage roof, one above the rear seats and the other in the baggage bay roof. Obviously I need to remove interior panels to get to them. I don't know which antenna feeds which radio. I suspect a coax or antenna / grounding issue (rather than the 430). Ill slide the 430 out, inspect the terminals, clean them with contact cleaner and have a look up behind the panel to see if I can see any obvious poor connection of the coax to the back of the 430 mount tray for a start. At the other end (the antenna end) whats the easiest way to determine which antenna is connected to which radio (without removing the headliner to both and disconnecting the antenna one by one- which is the obvious answer). Can I shield each antenna somehow and when I prevent the KX155 from receiving (thereby proving which is the 155 antenna) - meaning the other now is the 430 antenna ? ie how to target the right antenna without taking both antennae down? thanks for your help /any other tips on the matter! Justin
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