Originally Posted by
chewing4gum
This means that the tanker is also protected to a certain extent by the tyres and the car anti-static earthing strips - even if this is not the best way.
I still don't think you fully understand the difference between bonding and grounding. Lets try this way in more general terms.
If you only electrically bond (no grounding) the refuel truck to the aircraft, the bonding system will neutralize the static electricity potential difference between the refuel truck and the aircraft. In other words no static spark possible.
Now, if you only electrically ground (no bonding) the refuel truck to earth and only ground the aircraft to earth, there still could be a static electricity potential difference between the truck and aircraft. So in other words, a static spark is possible if you touch the refuel hose nozzle to the aircraft.
YouTube has a number of videos on static ignited fires where there is no bonding system used. Hence the reason aircraft refueling guidance and rules require bonding systems to be used between the refuel equipment and the aircraft. Make more sense?
I also believe that antistatic materials are installed in the hoses to protect them and prevent sparks if an earthing cable breaks. Additional protection. True?
Specified/certified flammable fluid hoses do have an integral bonding layer that can be used as the pump, filter, hose, and nozzle refuel bonding system to meet various guidance. So instead of a separate bonding cable to connect the truck to the aircraft, there usually is a shorter bonding cable connected at the nozzle which is connected to the aircraft before refuel ops.