MikeOH

Gawd, this is a depressing thread

I wonder how labor vs. raw materials/out-sourced parts vs. interior vs. avionics breaks down. Maybe Mooney could build 'green' airplanes (airworthy) and owners could fly them to their interior and avionics shops as they see fit.

Sadly, can't say I didn't see this coming. Too few sold; too high price.

Not a doc, but there are TWO differences that come to mind vs. 'holding your breath.' One, you don't realize the oxygen is NOT in the atmosphere you are breathing and you breath it OUT of your lungs. Two, the partial pressure at altitude is very low (doh!), there's not as much O2 even if you do hold your breath it's not going to last 'as long.' I imagine these tables assume you are breathing, not holding your breath.

Here's my theory: You have a 'weak/intermittent' short to ground on the the #2 comm radio's PTT input. Something internal to the the PMA450 is providing a 'pull-up' path to the #1 comm's PTT input which prevents #2 from going to TX most of the time (i.e., when the 'short' is weak...when it is a 'strong' short to ground #2 transmits) AS LONG AS #1 has power. When you pull #1`s CB, that 'pull-up' is now gone and #2 goes to TX continuously. One way to check this is to put BOTH transmit (pilot and co-pilot) select switches to comm #2...my guess is that comm #2 will go to continuous TX as the pull-up path to #1 will likely be disconnected. You're wire wiggling pretty much confirms an intermittent short, and Jerry's suggestion to check pin 30 to ground (if you can get to it) is a good one. Good luck with tracking down exactly where the wire is shorting...NOT fun! You might look for where wire bundles come in contact/wrap-around metal structures, especially sharp edges. Could be inside a connector back shell...shield wire/foil contacting the back of a pin.

We are in violent agreement! I've don a poor job of making that clear, I guess! Your post is EXACTLY why I find these kind of threads so amusing...all this discussion about regulatory minutiae and documentation. All this agonizing over where to get 'approved data',...what the FAA will accept,...blah, blah, blah. Find someone competent, show them the old part, and let them make a new one out of the same material. The hardest part is finding someone competent... and that is competent enough to know when what you want is beyond his abilities.

Makes sense. Thanks!

Curious what you are using for safety? I was taught never to trust the O-ring in an hydraulic jack. Always used safety stands with cars, and aircraft jacks have safety wheels built-in.

Well, now that's the rub, "...if done correctly." So, if the plane's in annual, in theory, that should mean "it's done correctly." But, I think we all know that isn't really always true. So, the question becomes, after the fact, will the FAA and/or the insurance company do a deep-dive on the logs to determine that an OPP was NOT 'done correctly?' My point is that I'm a lot more worried about the insurance being denied than the FAA. I seriously doubt claims have been denied over illegal OPPs. Hence, my amusement with all the hand wringing over how to 'properly' produce an OPP.

Which was my point about being pragmatic

I read all of these 'arguments' with a bit of amusement. It seems to me the REALITY is if INSURANCE claims will be DENIED if the cause of an accident is somehow related to an OPP. Absent that evidence (denied claims) I will continue to take a pragmatic approach to properly maintaining my aircraft. The FAA and their after-the-fact interpretation take a distant second place to whether my insurance will be in force.

I'm pretty sure I do; I'll check next time I go the hangar. Thanks for the suggestion!

Yes, quite possible the intercom was out for some time prior. If I'm not having a squelch problem I don't touch it. Honestly, I'm hoping it's just a string of bad luck. Much preferable to tracking down intermittent electrical issues in a 50 year old aircraft! I'll crawl under the panel and see if I can ID some common ground points and check their integrity. Beyond that, I'm going to take a 'wait and see' approach absent any other suggestions. Thanks, all

Hi Greg, Thanks for responding! Yes, at the moment, everything is working (except for the intercom that I haven't yet replaced/fixed). The Garmin, G3, and intercom are all on the CB switched Avionics buss. Nothing else has burned up....so, far. I have no idea if those items share a single point ground...and, no idea how to track that down...many wires, all white, bundled together, buried behind the panel and, I'm not sure my back is up to the task Does the electrical system have any (effective) overvoltage protection system? Probably well before the days of transorbs and the like, but curious if the system is 'clamped' at some voltage. What kind of spike could occur with a temporary VR/alternator failure? Thank you!

"Your papers, please!" And, you are here to tell us that is, "a total non-event," and are, apparently, only too happy to comply with gathering them all up. History is lost to many, I'm afraid. Sad