Mooney-Shiner Posted July 11, 2021 Report Posted July 11, 2021 Happy weekend, everyone. I had to send my electrical boost pump (Dukes 1499-00-19) to Aeromotors for the rebuild. While I reinstalling the rebuilt pump on the plane the same way it was previously installed, I realized how flimsy the installation of the ground wire was to the body of the airplane. I tried to reference the Parts Catalog and Service Manual to see where and how exactly the ground wire should be attached and what nut and washer should be used. But to my surprise there was no detailed the schematic on how the ground wire should be mounted, despite the fact that I view this part as a major airworthiness item. So I did my best to secure the ground wire to the floorboard best of my ability (as seen in the photos). Did anyone else ran into the same issue previously? Quote
RLCarter Posted July 11, 2021 Report Posted July 11, 2021 Not sure if it’s standard practice to have a ground and a clamp on the same stud (bolt) but I would think the clamp should go on first followed by the ground ring terminal then a star washer and nut. 1 Quote
cferr59 Posted July 11, 2021 Report Posted July 11, 2021 Here is a photo of mine. It is somewhat hard to see, but it looks like there is a similar approach. I thought it a bit strange when I reinstalled it, but it has been working since. 1 Quote
Eight8Victor Posted July 11, 2021 Report Posted July 11, 2021 (edited) Here is another hard to see photo but might be of some help. Edited July 11, 2021 by Eight8Victor 1 Quote
Mooney-Shiner Posted July 11, 2021 Author Report Posted July 11, 2021 7 hours ago, RLCarter said: Not sure if it’s standard practice to have a ground and a clamp on the same stud (bolt) but I would think the clamp should go on first followed by the ground ring terminal then a star washer and nut. Yep, thats why I hoped that there was some manual reference to proper install. My rationale by attaching the negative eye terminal of the pump under the clamp to attach it as close to the main body as possible to provide a solid ground. Additionally, if it is under the clamp and two nuts - this provided less likely possibility for the terminal to wobble out of attachment leaving me without the boost pump mid-flight. But yeah, I wish there was a better dedicated attachment location. Quote
Mooney-Shiner Posted July 11, 2021 Author Report Posted July 11, 2021 6 hours ago, cferr59 said: Here is a photo of mine. It is somewhat hard to see, but it looks like there is a similar approach. I thought it a bit strange when I reinstalled it, but it has been working since. I can see that you attachment has AN365 self-locking nut, which make better sense to me than my own set up. I don't like the fact that my nut is not self-locking, which is not helping with accidental detachment due to the frame vibration. Or maybe I'm just overthinking this... Quote
kortopates Posted July 11, 2021 Report Posted July 11, 2021 (edited) 7 minutes ago, ukrsindicat@yahoo.com said: I can see that you attachment has AN365 self-locking nut, which make better sense to me than my own set up. I don't like the fact that my nut is not self-locking, which is not helping with accidental detachment due to the frame vibration. Or maybe I'm just overthinking this... Did you consult your IPC for proper hardware? That specifies what to use. Edited July 11, 2021 by kortopates Quote
Mooney-Shiner Posted July 11, 2021 Author Report Posted July 11, 2021 Just now, kortopates said: Did you consult your IPC for proper hardware? That specifies what to use. Kortopates, Unlike the detailed IPCs of Encore, the Beatles-era IPCs of As-Fs provide rather marginal info of some areas of aircraft. As mentioned above, the rigging of boost pump is one of those areas. Quote
kortopates Posted July 11, 2021 Report Posted July 11, 2021 17 minutes ago, ukrsindicat@yahoo.com said: Kortopates, Unlike the detailed IPCs of Encore, the Beatles-era IPCs of As-Fs provide rather marginal info of some areas of aircraft. As mentioned above, the rigging of boost pump is one of those areas. In that case, AC 43.13-1b Chapter 11 provides the guidance in the absence of manufacturer specific guidance. I am sure your fine with that, but woud measure resistance between your point for the boost pump ground and at another known good ground at the firewall or battery just to be sure it tests good. 1 Quote
Mooney-Shiner Posted July 11, 2021 Author Report Posted July 11, 2021 1 hour ago, kortopates said: In that case, AC 43.13-1b Chapter 11 provides the guidance in the absence of manufacturer specific guidance. I am sure your fine with that, but woud measure resistance between your point for the boost pump ground and at another known good ground at the firewall or battery just to be sure it tests good. Thank you! I will look up AC 43.13-1b. Any suggestions on the good ground on plane's underbelly? Quote
carusoam Posted July 11, 2021 Report Posted July 11, 2021 Some really good input so far… I invite @M20Doc for such tech discussions… Don’t be afraid to use new hardware… when it comes to locking nuts, they sometimes give up their holding strength when re-used… Best regards, -a- 1 Quote
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