A BEECH E90 AFTER SVCING THE MEDICAL OXYGEN TANK AND PRIOR TO REMOVAL OF THE SVCING HOSE A FLASH FIRE OCCURRED WHEN THE SVCING LINE WAS VENTED ONTO A 2 INCH FUEL SPOT WHICH RESULTED IN INJURY TO THE PLT.

Narrative

THE COMPANY HAD INSTRUCTED PLTS TO FILL THE MEDICAL OXYGEN ON THE AIRPLANES. WHEN I CAME BACK FROM A FLT EARLIER IN THE DAY; I NOTED THAT THE OXYGEN WAS LOW BUT WAS TOLD THAT AT THIS BASE (NOT MY USUAL BASE) OXYGEN WAS FILLED BY WHOEVER WAS NIGHT PLT. I WAITED UNTIL HE ARRIVED; THEN TOLD HIM THAT WE NEEDED OXYGEN. HE PROCEEDED TO FILL THE MEDICAL OXYGEN. I WENT OUTSIDE TO SEE IF I COULD HELP. WHEN THE FILLING WAS COMPLETE HE SHUT OFF THE OXYGEN TANK ON THE DOLLY AND I WENT INTO THE PLANE TO SHUT OFF THE TANK THERE. HE THEN WENT TO VENT THE LINE. THIS PARTICULAR VENT POINTS DOWN AT THE RAMP. THIS DAY IT WAS POINTED (BY CHANCE; NOT DESIGN) AT A 2 INCH DIAMETER FUEL STAIN. WHEN THE OXYGEN HIT THE STAIN; SPONTANEOUS COMBUSTION OCCURRED CAUSING A SMALL EXPLOSION; BURNING THE OTHER PLT'S ARM. HE WAS TAKEN TO THE HOSPITAL WITH FIRST; SECOND; AND THIRD DEGREE BURNS. IF THE OXYGEN CART HAD BEEN POSITIONED 1-2 FT IN ANY OTHER DIRECTION; THE INCIDENT WOULD NOT HAVE HAPPENED. ALSO; IF THE VENT HAD NOT BEEN POINTED DOWN; IT WOULD NOT HAVE HAPPENED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED IT WAS NORMAL PROC TO FILL THE MEDICAL OXYGEN TANK LOCATED INSIDE THE ACFT WITH AN OXYGEN SVC CART. THE RPTR SAID AFTER SVCING THE ACFT OXYGEN; THE ACFT TANK VALVE WAS CLOSED AND THE SVC CART TANK WAS CLOSED AND THEN THE SVC LINE WAS VENTED. THE RPTR STATED THE VENT LINE POINTED DIRECTLY AT THE RAMP SURFACE WHICH HAD A SPOT OF FUEL AND IT CAUSED A SMALL EXPLOSION INJURING THE PLT SVCING THE TANK. THE RPTR SAID THE ACR HAS REVISED ALL OXYGEN SVCING PROCS AND PLTS WILL NOT SVC OXYGEN.