FAA INSPECTOR OBSERVED INADEQUATE DEICING OF AN LTT TURBO PROP RESULTING IN DEICER RETURNING AND COMPLETING THE JOB WITH THE ENGS RUNNING.

Narrative

AT SEATAC IT HAD BEEN SNOWING. THE SNOW WAS NOT STICKING (THE TEMP WAS 33 DEGS WITH LIGHT WINDS). THE CAPT MADE THE DECISION TO DEICE WITH GLYCOL EVEN THOUGH THE RAMP HAD SWEPT THE WINGS AND THEY WERE ENTIRELY FREE OF ANY ACCUMULATION. THE TAIL HAD NOT BEEN SWEPT SO WE HAD THE DEICER INFORMED THAT THE EMPENNAGE NEEDED TO BE DEICED. MEANWHILE WE LOADED PAX AND COMPLETED THE MANIFEST. WE CLOSED THE MAIN CABIN DOOR AND THE TAIL WAS DEICED. THEY ALSO WENT AHEAD AND DEICED THE WINGS. AT THE COMPLETION OF THE DEICING; WE STARTED ENGS. JUST THEN ONE OF OUR MECHS CAME OUT OF THE MAINT BUILDING AND TOLD OUR MARSHALLER THAT WE HAD SNOW STILL ON THE HORIZ. (AT THE TIME; WE DID NOT KNOW WHAT THE MECH WAS TELLING THE RAMP AGENT.) THE RAMP AGENT SIGNALED TO US TO CALL OPS WHICH I DID. THEY INFORMED ME THAT THE FAA HAS BEEN OBSERVING THE DEICING AND HAD NOTICED SNOW STILL ON THE HORIZ. (THE FAA OBSERVER TOLD OUR MECH WHO THEN INFORMED THE RAMP.) THEY WENT ON TO SAY THAT THE DEICER WAS GOING TO RETURN AND SPRAY THE TAIL. I SAID 'OKAY.' THE DEICER RETURNED AND DEICED NOT ONLY THE TAIL BUT THE FUSELAGE AND OUR WINDSCREEN. THE PERSON DRIVING THE DEICER DROVE FROM BEHIND THE TAIL TO THE R SIDE OF THE FUSELAGE TO JUST OUTSIDE OF THE R WING AND THEN FORWARD. THE ACTUAL DEICER IN THE BASKET WAS ARCHED UP AND OVER THE WING; WHILE THE ENGS WERE RUNNING. DANGEROUS!!