Function of fuel tank attach bolt

[pa38112]

I am re-installing my fuel tank after a repair (RV6), and I am perplexed by the arrangement of the bolt that attached the tank to the fuselage - a bolt into a rivet nut over a slot ??? What is this bolt suppose to do ?

[airguy]

It's supposed to hold it tight enough to handle normal flight forces, but loose enough to let it break away in an impact instead of transferring impact forces to the fuselage.

[Bevan]

The bolt supports the front end of the tank. It is my understanding that the slot used to be a hole (in earlier RV models) but was changed to a slot to allow the bolt to slide out during certain crash scenarios allowing the fuel tank a better chance at staying intact at the inboard rib.

Bevan

[skylor]

The tank bracket and bolt is designed to support vertical loads, either upward lifting load of the tank from aerodynamic lift at high angle of attack or downward loading during a hard landing with full tanks. The joint is designed to slip laterally in case of wing separation during a crash landing so that the root rib of the tank doesn't rupture.

Skylor