EMS HELI EXPERIENCES WIND GUSTS WHICH SLAM ROTOR INTO TAIL ROTOR.

Narrative

A SINGLE PLTED EMS HELI WITH 1 FLT NURSE CREWMEMBER AND A 3 PERSON MEDICAL TEAM WITH INFANT PATIENT PREPARING FOR DEP FROM A ROOF TOP HELIPAD. THE HELI IS SITTING ON A PAD ORIENTED N/S. THE HELI IS FACING NNW DUE TO WINDS AND GUSTS BOTH DUE TO AMBIENT CONDITIONS AND OBSTRUCTIONS: 12 STORY BUILDING TO THE NW 200 FT AWAY AND A 10 STORY BUILDING 400 FT TO THE N. WIND AT AN ARPT 10 NM E WAS 290 15G30 AND WIND AT AN ARPT 10 NM W WAS 330/13. DURING INITIAL START OF ENG #1 WITH ROTOR BLADES AT LOW RPM; A LOW THUD NOISE WAS HEARD BY THE PLT AND CREW. THE START SEQUENCE BARELY GOT TO FLT IDLE WHEN SHUTDOWN WAS INITIATED IN ORDER TO INVESTIGATE. ENGS WERE OFF AND ROTORS SLOWING. FLT NURSE EXITED L SIDE OF ACFT; INSPECTED L SIDE; THEN WALKED AROUND FRONT OF HELI TO VISUALLY INSPECT THE R SIDE. THE FLT NURSE THEN CALLED THE PLT'S ATTN TO AN APPARENT NICK IN THE VERT STABILIZER. PLT RECHKED THAT ALL SWITCHES WERE OFF IN THE COCKPIT AND EXITED THE ACFT TO INSPECT. BOTH CREWMEMBERS THEN WALKED TO L SIDE OF ACFT; NURSE TOLD MEDICAL TEAM TO STAY IN THE ACFT. THE PLT AND NURSE BEGAN CALLING TO HOSPITAL PERSONNEL THAT WERE STANDING OFF PAD TO GET EXTRA PERSONNEL TO EXPEDITIOUSLY UNLOAD THE INCUBATOR. THE INDIVIDUAL COULD NOT HEAR THE CREWMEMBERS CLRLY SO THEY MOMENTARILY WALKED FROM THE ACFT TOWARD THE HOSPITAL TO BE HEARD. AS THIS OCCURRED; A GUST OF WIND CAUSED THE SLOWLY TURNING BLADES TO CONTACT AND BREAK A VERT STABILIZER AND BEND A ROTOR BLADE. AT THE SOUND OF THE IMPACT THE MEDICAL TEAM BEGAN EXITING THE ACFT. THE FLT NURSE AND PLT YELLED FOR THE CREW TO STAY ABOARD BUT ONE PERSON GOT OUT; SAW THE TURNING BENT ROTOR BLADE AND STAYED CLOSE ABOARD. THE BLADE STOPPED IN ONE REVOLUTION. CONTRIBUTING FACTORS: ACFT PUBLISHED LIMITATIONS. START LIMITATIONS FOR THIS HELI IS 50 KTS HEAD ON; 45 KTS OTHER DIRECTIONS. THE RIGID ROTOR SYS OF THIS ACFT IS TOUTED BY THE MANUFACTURER AND TAUGHT BY THE COMPANY TO BE THE SAFEST IN THESE CONDITIONS. THE RPTED AND ACTUAL WINDS GAVE THE PLT NO REASON TO ANTICIPATE THIS PROB. THE PLT AND THE HOST HOSPITAL'S CREW MEMBERS (FLT NURSES AND PARAMEDICS) WORK TOGETHER DAILY AND IT IS NOT UNCOMMON FOR CREWMEMBERS TO BE OUTSIDE THE ACFT DURING START AND SHUTDOWN. THE WIND CONDITIONS WERE NOT NOTED NOR FELT TO BE EXCESSIVE; THEREFORE A THREAT TO PERSONNEL OUTSIDE THE ACFT WAS NOT PERCEIVED. AFTER THE NURSE INDICATED DAMAGE TO THE STABILIZER AND THE PLT SUBSEQUENTLY LOOKED AFT AND SAW IT; HE INITIALLY JUDGED THE OCCURRENCE AS A FREAK INCIDENT. WITH THE ENGS OFF AND ROTOR SLOWLY TURNING; THE PLT DECIDED TO INSPECT THE L SIDE OF THE ACFT; AND IF NO FURTHER DAMAGE; EXPEDITE THE TRANSFER OF THE TEAM AND PATIENT. THE FLT NURSE HAD INDICATED THAT THE BABY WAS CRITICAL AND NEEDED TO GET BACK INTO THE HOSPITAL. IT APPEARS THAT THE PLT'S CONFIDENCE IN THE ACFT BASED ON AT LEAST 1000 FLTS IN IT AND THE KNOWLEDGE OF THE LIMITATIONS GAVE A FALSE SENSE OF SECURITY; INSTEAD OF GREATER ALARM; IN JUDGING THE MINOR STRIKE AS A FREAK OCCURRENCE AND NOT AS A PRECURSOR OF WORSE TO COME. THUS THE SECONDARY MISSION OF PATIENT AND MEDICAL CREW DISPOSITION BECAME PRIMARY. THE FLT NURSE; A VETERAN OF 10 YRS FLYING; ALSO PERCEIVED NO THREAT AND WENT ABOUT HER DUTIES NORMALLY. THE PLT COULD HAVE ALTERED THE CHAIN OF EVENTS BY COMMANDING THE NURSE TO GET BACK INTO THE HELI AFTER THE FIRST STRIKE WAS NOTED AND NOT LET ANYBODY DISEMBARK UNTIL ALL MOVEMENT CEASED. THIS ACTION; HOWEVER; MAY ONLY BECOME AUTOMATIC WITH HEIGHTENED AWARENESS OF THE SUSCEPTIBILITY OF THIS ACFT TO ROTOR/FIN STRIKES IN CONDITIONS LESS THAN THOSE SPECIFIED IN THE MANUAL. HELI USERS NEED TO EVALUATE THE PROCS FOR STARTUP AND SHUTDOWN UNDER VARIOUS CONDITIONS SUCH AS ROOF TOP PADS; WIND DIRECTION AND GUST SPREAD; AND DEVELOP APPROPRIATE AMENDMENTS. THIS HELI'S ROTOR BRAKE IS ALMOST USELESS. IF IT WERE IMPROVED TO MATCH THE PERFORMANCE OF THOSE IN AN H-1 OR A COBRA; IT WOULD BE ABLE TO STOP THE ROTORS N HALF THE TIME/REVOLUTIONS AND WOULD BE STRONG ENOUGH TO DO ROTOR BRAKE STARTSIN GUSTY CONDITIONS; LESSENING THE SUSCEPTIBILITY TO ROTOR/FIN STRIKES. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: RPTR STATES THE HELI PAD WAS ABOUT 2 STORIES HIGH AND HE BELIEVES THE WIND PROBABLY BURBLED FROM AROUND THE NEARBY BUILDINGS OR POSSIBLY FROM BELOW THE HELI PAD BUILDING AND THREW THE BLADE UP THEN SNAPPED IT DOWN. AS HE STATES; THE RIGID BLADES ARE SUPPOSED TO PREVENT THIS KIND OF INCIDENT. THEY ARE ALSO SHORTER BLADES THAN MOST AND THERE ARE 4 OF THEM. THE WIND APPEARED TO BE NO FACTOR AND WAS WELL WITHIN PRESCRIBED LIMITS. A SIMILAR INCIDENT OCCURRED ABOUT 10 YRS AGO AND CAUSED CONCERN BUT NO CHANGES WERE DEEMED NECESSARY. IT DOES NOT SEEM TO BE A DESIGN PROB BUT SOMETHING HELI PLTS MUST BE AWARE OF. HIS GREATER CONCERN IS THE ROTOR BRAKE. HE HAS FLOWN SEVERAL MIL HELIS AND THOSE BRAKES REALLY STOP THE ROTORS. THIS IS LIKE A DISC BRAKE ON A CAR AND IS NOT EFFECTIVE UNTIL THE BLADES HAVE ALMOST STOPPED. IF THIS BRAKE WERE BETTER A ROTOR BRAKE START WOULD BE POSSIBLE AND THE BLADES WOULD START AT A HIGHER SPD AND PREVENT THIS KIND OF INCIDENT. THIS MATTER HAS BEEN BROADLY DISSEMINATED IN THE EMS COMMUNITY AND IS BEING DISCUSSED WIDELY.