Narrative:

Upon return from 1 hour 42 min sightseeing tour and passenger discharge, I requested to west 30TH st advisory that I would like to reposition from transient pad to the fuel pad. They reported the wind as 030 at 4 KTS. I was required to back the aircraft out of transient due to obstructions in front and on either side of the aircraft. I brought the aircraft to a 3' hover and performed a hover check. I then proceeded to back the aircraft out and felt the tail dip due to a gust of wind from the rear. At this time I experienced a high frequency vibration and immediately set the aircraft down. No abnormal feedback was felt in the tail rotor pedals. Upon immediate shutdown I was informed that someone had been injured inside the tour company trailer. I insured that the injury wasn't serious and called an ambulance, then returned to the aircraft for a post-flight inspection and found the tail rotor had struck an electrical cable running along the edge of the bulkhead. This caused tail rotor blade tip damage. One of the bolts in the end of the tail rotor blade tip had been flung off the blade and through the window of the trailer. It struck the camera of the injured man and impacted the camera into his face. He sustained a small cut on the nose and was treated by paramedics and released. Several factors can be attributed to the cause of this incident. Transient pad at west 30TH st is a relatively small area for aircraft operations, especially when an aircraft is on spot one, as was the case. The dimensions are 59' X 59'. To the north is a large fence about 10' tall, east is the trailer, south is parking spot #1, and west is the hudson river. The aircraft has a 35' rotor disc and an overall length of 42.5'. Another factor is the slope of the pad from the bulkhead to the trailer. The center of the pad sits approximately 8' lower than the edge of the bulkhead. A backwards hover is deceiving because the actual clearance of the aircraft is much less than the apparent clearance. This type aircraft has a tail rotor guard that extends off the lower half of the vertical fin. This particular tail guard provided no protection from the tail rotor strike because the guard was beyond the bulkhead. Another design is available on a half loop below the tail rotor and provides protection from such a strike. Had this tail rotor guard been installed, the incident most likely would not have occurred. The most significant factor was the gust of wind from the tail. Although the wind was light and variable, the swirling winds off the buildings can be very significant. It is possible, a redesigning of the heliport to permit more room for aircraft movement would help prevent a recurrence of this situation.

Related reports:

Google
 

Original NASA ASRS Text

Title: SMA HELICOPTER IN HOVER FOR GND REPOSITIONING HITS TAIL ROTOR BECAUSE OF DOWN GUST AFT.

Narrative: UPON RETURN FROM 1 HR 42 MIN SIGHTSEEING TOUR AND PAX DISCHARGE, I REQUESTED TO W 30TH ST ADVISORY THAT I WOULD LIKE TO REPOSITION FROM TRANSIENT PAD TO THE FUEL PAD. THEY REPORTED THE WIND AS 030 AT 4 KTS. I WAS REQUIRED TO BACK THE ACFT OUT OF TRANSIENT DUE TO OBSTRUCTIONS IN FRONT AND ON EITHER SIDE OF THE ACFT. I BROUGHT THE ACFT TO A 3' HOVER AND PERFORMED A HOVER CHECK. I THEN PROCEEDED TO BACK THE ACFT OUT AND FELT THE TAIL DIP DUE TO A GUST OF WIND FROM THE REAR. AT THIS TIME I EXPERIENCED A HIGH FREQ VIBRATION AND IMMEDIATELY SET THE ACFT DOWN. NO ABNORMAL FEEDBACK WAS FELT IN THE TAIL ROTOR PEDALS. UPON IMMEDIATE SHUTDOWN I WAS INFORMED THAT SOMEONE HAD BEEN INJURED INSIDE THE TOUR COMPANY TRAILER. I INSURED THAT THE INJURY WASN'T SERIOUS AND CALLED AN AMBULANCE, THEN RETURNED TO THE ACFT FOR A POST-FLT INSPECTION AND FOUND THE TAIL ROTOR HAD STRUCK AN ELECTRICAL CABLE RUNNING ALONG THE EDGE OF THE BULKHEAD. THIS CAUSED TAIL ROTOR BLADE TIP DAMAGE. ONE OF THE BOLTS IN THE END OF THE TAIL ROTOR BLADE TIP HAD BEEN FLUNG OFF THE BLADE AND THROUGH THE WINDOW OF THE TRAILER. IT STRUCK THE CAMERA OF THE INJURED MAN AND IMPACTED THE CAMERA INTO HIS FACE. HE SUSTAINED A SMALL CUT ON THE NOSE AND WAS TREATED BY PARAMEDICS AND RELEASED. SEVERAL FACTORS CAN BE ATTRIBUTED TO THE CAUSE OF THIS INCIDENT. TRANSIENT PAD AT W 30TH ST IS A RELATIVELY SMALL AREA FOR ACFT OPERATIONS, ESPECIALLY WHEN AN ACFT IS ON SPOT ONE, AS WAS THE CASE. THE DIMENSIONS ARE 59' X 59'. TO THE N IS A LARGE FENCE ABOUT 10' TALL, E IS THE TRAILER, S IS PARKING SPOT #1, AND W IS THE HUDSON RIVER. THE ACFT HAS A 35' ROTOR DISC AND AN OVERALL LENGTH OF 42.5'. ANOTHER FACTOR IS THE SLOPE OF THE PAD FROM THE BULKHEAD TO THE TRAILER. THE CENTER OF THE PAD SITS APPROX 8' LOWER THAN THE EDGE OF THE BULKHEAD. A BACKWARDS HOVER IS DECEIVING BECAUSE THE ACTUAL CLRNC OF THE ACFT IS MUCH LESS THAN THE APPARENT CLRNC. THIS TYPE ACFT HAS A TAIL ROTOR GUARD THAT EXTENDS OFF THE LOWER HALF OF THE VERTICAL FIN. THIS PARTICULAR TAIL GUARD PROVIDED NO PROTECTION FROM THE TAIL ROTOR STRIKE BECAUSE THE GUARD WAS BEYOND THE BULKHEAD. ANOTHER DESIGN IS AVAILABLE ON A HALF LOOP BELOW THE TAIL ROTOR AND PROVIDES PROTECTION FROM SUCH A STRIKE. HAD THIS TAIL ROTOR GUARD BEEN INSTALLED, THE INCIDENT MOST LIKELY WOULD NOT HAVE OCCURRED. THE MOST SIGNIFICANT FACTOR WAS THE GUST OF WIND FROM THE TAIL. ALTHOUGH THE WIND WAS LIGHT AND VARIABLE, THE SWIRLING WINDS OFF THE BUILDINGS CAN BE VERY SIGNIFICANT. IT IS POSSIBLE, A REDESIGNING OF THE HELIPORT TO PERMIT MORE ROOM FOR ACFT MOVEMENT WOULD HELP PREVENT A RECURRENCE OF THIS SITUATION.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.