Ground Block Horror Show [0.5 hours]

I ordered a 48 pin ground block from Aircraft Spruce, P/N 07-03464. The block is actually made by B&C Aero. Nothing much to it, just a heap of Faston terminals soldered to a brass strip, with a brass bolt at one end.

Unfortunately, whoever made the block has flowed solder all over the terminals, filling all of the locating holes. There are blobs of solder clumped onto the terminal faces, and flux/resin residue all over the place. In contrast to this, the “representative” photo of the product on ACS’s web site shows the holes clear and the contacts in their original condition.

Faston connectors have a “dimple” on them that positively locates the terminal into a hole on the spade. This locates the terminal to ensure proper mechanical mating, maximum contact area, and provides a measure of protection for the connection from coming loose or free due to vibration.

Since the holes are all filled in with solder on these terminals, this proper mating will not occur, and connections to this ground block could easily come loose and fall off. The solder blobs on the spades will cause distortion of the Faston connector, permanently deforming the lugs and causing a poor connection over time. Moreover, the contact resistance and its properties over time are an unknown quantity, since the original contact material extensively researched by the Faston terminal manufacturer has been replaced by whatever grade of solder was used under the unknown application conditions that existed when this ground block was made.

If ground points start degrading or falling off in flight, the outcome could be very serious, and potentially fatal. Anyone who has ordered one of these products should check its condition before installing it.

I’ve asked ACS for a refund. I could reflow it and clear out the holes, but the blades would still be covered in solder residue and that defeats the dimensional tolerance and contact material the original manufacturer of the Faston contacts has in place.

Description of detent and hole in web section
Product as advertised on ACS’s website
  • bc_gnd2
    Solder and flux all over contacts, holes filled
  • f36a
    Solder and flux all over contacts, holes filled
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