Installing rear seat shoulder harness P337 ?
 

We just sold the Riley Sky Rocket P337 that I look after and the "new" owner asked to install shoulder harness for the rear seats ( 3 & 4th).


I checked the IPC and indeed there are PNs for them, but when I pulled the headliner to check for provisions, I found just a small 3/16s rivnut . A quick check of the pilot & co-pilot shoulder harness provisions shows 4/16s nut-plates in a beefed up bulkhead member.

Clearly this rivnut is not structurally sound to handle seat belt loads.

Readers ?

Does the parts manual give any info on this? Maintenance manual?

What about aftermarket options?

I started with the IPC and MM but they give almost no info on the mounting fixture.

I 've checked the usual seat belt STC suppliers but no joy.