scope:

Description of Driving Event:

A fire started at the flight operations aircraft fueling station when a pumping station was in the process of being connected to a new, in-ground, aviation fuel storage tank. Residual fuel had been left in the refueling unit because the connection was to be made with no disruption to any of the unit piping. The workers installing the unit, when faced with a six inch difference in the tank piping from the unit inlet, decided to modify the piping. When the workers broke into the unit piping and saw some residual fuel leaking they assumed the amount to be negligible. A stand was set up within 10 feet of the pipe opening and a grinding operation was started to add a short section of pipe.

The investigation committee determined that the ignition source of the fire was from sparks generated by the grinding operation.