Some more info copied from the AD in Australia:
Background: An operator reported a failure of this type of fuel pump in service. Subsequent investigation revealed that the cause of the pump failure was that one of the two screws and nuts holding the gas return connector to the top of the motor housing had
become unscrewed. The screw dropped between the motor rotor and the stator where
it caused the short circuit resulting in the circuit breaker tripping. Further
investigation concluded that this was due to the inadequate locking mechanism of the
nut and the screw being incorrectly torque tightened. Consequently, the integrity of the pump’s explosion proof housing is not kept and arcing may occur during the failure. In case the pump is not submerged in fuel, an explosion could occur both in-flight or on ground.
Installation of pumps with a different PN and/or pumps PN 568-1 -27202- 005 with a
serial number outside the batch defined in the applicability of the AD is considered a
terminating action of this AD.
This amendment includes an inspection and modification requirement which
addresses the unsafe condition. Incorporation of that modification will also terminate
the actions detailed in this AD.
The original issue of this AD became effective on 8 May 2006.