Search the Community

I bought a 1982 M20J 201 back in April and I took it for my first night flight the other evening. I didn't notice anything unusual until I was in flight for several minutes, at which point the panel lights started changing intensity at a rate of perhaps 2 Hz...bright-dim-bright, a bit random. I then looked at the ammeter and the needle swings pretty wide left and right of zero in time with the panel light fluctuations. I have a JPI EDM-700 and it logs various voltages from 13.6 to 14.5. The problem is also intermittent. Most times it doesn't happen until in flight (I've made a point of checking for it every time I fly now), and it will just stop happening for many seconds or even minutes at a time, then starts up again. Sometimes it happens on taxi to runway, sometimes not. I can't yet figure out what causes it to happen.. It's also probably a long-standing issue that I only happened to notice the other night since it was the first time I'd actually flown with the panel lights turned up and visible. I downloaded the last 50 flights from the EDM-700 yesterday and as far back as it has been recording (just since June- I'm in IR training in this plane), it has been recording variable voltage like this. Nothing else seems wrong and only direct DC loads like the panel lights (and presumably the landing light) are clearly affected. I just re-tensioned the alternator belt but that didn't help. The belt is old and I got a good look at the inner surfaces between the ridges - it has some cracking and in general looks worn, but I'm not sure it could be slipping for minutes at a time and then just stop slipping for a while, etc. And it's definitely under good tension as of this evening but a test flight after that revealed no change in the behavior. I also inspected the wires on the back of the alternator. The field wire (I think it's the field wire) is a bit damaged a few inches away from where it connects to the alternator (like, the insulation was nicked or something at some point), but it doesn't seem like it is a broken connection, just some exposed conductor for about 1/8" along the wire in free space there. I decided not to disturb it since I was tensioning the belt and wanted to address one variable at a time. Anyone else ever see a problem like this?

Yesterday I tested the Standby Alternator in my Ovation 2 29-0363 (905 hours TTIS) all according to the published procedure, and it failed. To track down the fault the top cowl was removed, the prop rotated by hand, and we found the alternator was not rotating, so the problem seems to be the shear coupling. Have any other readers experienced the shear coupling failure, and at what TTIS? Was the alternator replaced or overhauled with the shear key replacement? It seems that the alternator is essential for TKS equipped Ovations, but not essential for non TKS. I'm not overly confident flying with the standby U/S because the G1000 equipped Ovation 2 needs plently of power, but then I accumulate some 1000 hrs on my first Ovation 1 (29-0156) in some of the most remote areas of Australia without the luxury of a standby.

When reading the electrical schematic, each line is annotated with something like 21WE17B20. I assume this is to help identify the line at the source and destination. Do the numbers have any other significance like wire gauge or voltage or anything? PS. Are the fuses indicated anywhere on the schematic? Not a lot of experience reading these things.

My 78' M20J has had a couple of odd electrical happenings the past couple of flights and want to see if there are any experts or fellow owners who have had the same issues and found the culprit or if these could potentially be all from a similar issue? Issues: - Wobbling Ammeter (going to first try Don Maxwells suggestion of cleaning Master Switch and connections here), but I have noticed that over the last two flights the high/low warning light has come on and instead of a slight wobble it is doing about a 1/4 deflection in the wobble that is pretty big. Unfortunately I just found the article so I need to go fly and see if putting pressure on the contacts stops the issue. In flight intermittently the voltage will go to 14.3V when wobbling and then return to a normal 13.9V-14V reading. - I replaced the Battery/Master solenoid (with sign off from A&P) because it was original to the airplane and was in bad shape with the SkyTec PMA'd one, but when I turn the master on it always clicks the solenoid, but does not always immediately power everything up. I usually have to cycle it a couple of times to get it to actually provide power. Once it works it works though and has never shut off after engaging. I put a volt meter on it and the battery has around 12.9V on the front of the Solenoid but only 12.3V once the master is turned on on the back side of the solenoid. Is this a normal drop? On my JPI 830, it is around 11.9V in the cabin. I have not removed the JPI to get a reading at the terminal, that is just the reading on the screen. Plane starts fine and seems to have enough power. Is this kind of drop pretty normal under load and I am being overly paranoid or does that sound like something is amiss? - I pulled the top and bottom cowl to inspect my alternator and starter wiring and I have concerns about wire integrity and potential corrosion. As you can see from the photos I attached, there is a seemingly pointless splice in the line going to the starter (image 0598) and the alternator wiring has lost a majority of its shielding and is fraying badly. Is it time to replace one or both of these or is this "normal"?

Hi All, I just returned from my first business trip in N252DR, a 1986 252 Rocket. She had been parked for a while before I bought her but Jimmy Garrison & Don Maxwell provided an accurate assessment of her condition. Maxwell finished an extensive annual the last week of August & the flight home from Longview TX to Ocala FL was nearly trouble-free. Last week I made a 1700 mile trip to Columbus OH, Destin FL, then back to Ocala. A few (hopefully easily fixable) bugs appeared and I'd really appreciate a little crowd-sourced troubleshooting advice. Here's what I found: Panel lights, which were working, went inop. Instrument lights worked fine and so did my three flashlights that I rechecked en route when I realized the panel lights wouldn't come on. EDM-700 tach wildly erratic. Ship's tach worked fine. No sign of actual RPM fluctuation. Ship's CHT gauge wildly erratic. EDM-700 CHT steady on all 6 cylinders. Occasional weak & unreadable on comm 1, a G530W. Switched to comm 2, an old King 165, and was loud & clear. KAP 150 autopilot preferred to stay 100' below selected altitude and about 10 degrees right of selected heading. En route GPS nav would often try to fly 10+ degrees difference between DTK and TRK. HSI was spot on during GPS approaches. I do have a digital copy of the 252 maintenance manual, parts catalog, & POH which I am happy to share with anyone if they need it to help me troubleshoot these problems :-) Any advice is much appreciated- I've been out of the aviation world for a while and am thankful to find this great community on Mooneyspace. Thanks!! P.S. does anyone have an electric tow bar for sale?

Good Day Mooneyspace folks, I look forward to any insights related to the following issue: Fresh annual, engine run-up to validate a tachometer replacement. Prior to engine shutdown, noticed "high low volts" flashing on annunciator panel (s/n 24-1580, 14v electrical system). Problem fixed by replacing female electrical terminal at Master Switch. Thanks

When I test my annunciator panel at run up (1900 rpms) everything is normal, however if I test it in cruise (2500 rpms) it pops the Annunciator circuit breaker. Has anyone else experienced this? Why do you think this happens?