Transport Canada CF-2023-51

Requires installation of a frangible split plastic grommet at the airframe cutout where the sump drain fitting passes through to prevent the fuel drain quick disconnect valve from catching on the airframe cutout and to reduce the load on the valve body by preventing metal-to-metal contact following an impact. Prompted by finding during fuel system crash impact testing for a modification certification that when the airframe was rolled to the left to be inverted after the drop test, fuel leakage was observed from the fuel drain quick disconnect valve located at the sump drain port. The knurls on the locking sleeve of the fuel drain quick disconnect valve contacted the airframe cutout upon impact, resisting the fuel bladder rotational action and causing deformation of the poppet, which led to the valve remaining in the partially open position and subsequent fuel leakage.