JDK
Considering that the fuel dump by an F-111 was to rapidly reduce weight following a heavy take off involving a substantial loss of thrust the USAF test centre at Edwards AFB very carefully and with some initial trepidation determined that the flame front would not get close enough to singe the back end.
I believe the resident RAAF TP at Edwards was involved and was able to reassure the RAAF on all counts of safety.