|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : zzz.airport|
|Altitude||agl single value : 70|
|Operator||general aviation : corporate|
|Make Model Name||S-76/S-76 Mark II|
|Operating Under FAR Part||Part 91|
|Flight Phase||descent : approach|
|Route In Use||approach : visual|
|Affiliation||company : corporate|
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Experience||flight time last 90 days : 30|
flight time total : 13560
flight time type : 2290
|Affiliation||company : corporate|
|Function||flight crew : first officer|
|Qualification||pilot : atp|
pilot : cfi
|Experience||flight time last 90 days : 40|
flight time total : 13000
flight time type : 1000
|Anomaly||inflight encounter other|
|Independent Detector||other flight crewa|
|Resolutory Action||none taken : anomaly accepted|
|Problem Areas||Flight Crew Human Performance|
During short final to a private helipad; the helicopter main rotor struck a tree branch. The helicopter was decelerating for the landing and was at 70 ft AGL and 40 KIAS at the time of the occurrence. I was the PIC and PNF in the left seat. Monitoring instruments; I made the '70 AGL/40 KIAS plenty of clearance on the left' callout just prior to the helicopter rotor striking the tree branch. The sic was the PF from the right seat. Surface winds were reported 280 degrees at 9 KTS. Approach course was 040 degrees. The left crosswind and resulting left wind correction angle gave the right seat pilot the best visual cues for the approach flown. There was only a momentary faint sound and vibration at the time of the strike and no other unusual sounds or vibrations as the approach was to a hover and normal landing within 1 min of the strike. The aircraft was shut down after the landing at the helipad and inspection revealed 2 of the 4 main rotor tip caps were damaged. There were no injuries to any of the 3 passenger or 2 crew members. 2 of the passenger later stated that they were not even aware of the event at the time it happened. The S76 helicopter instrument panel and glare shield confign is poorly designed in relation to most pilot seat position that result in a compromise between forward visibility over the nose of the helicopter up to about 8 degrees positive pitch and still being able to view the upper portion of the instrument panel. Final approach attitudes are typically 12 degrees during deceleration and 8 degrees for hover. In order to maintain a full view of the approach path and landing area; the PF will normally 'kick' the helicopter out of trim and obtain a full view past the side of the glare shield; looking through the windshield and 'chin bubble' if necessary. Each pilot's lateral view opposite their seat position is almost nil during the deceleration attitude. The pilot flying an approach to a confined helipad must rely on clearance callouts from the PNF. Some of the newer model helicopters have glare shields that will slide fore and aft to meet the ergonomic needs of the pilot. We will look into the availability of a modification for our helicopter. The pilots flying this helicopter have considerable experience. We will review our criteria for utilizing this approach and the procedure for its use. We can certainly develop simulator training profiles for newly established procedures. We may abandon this approach if appropriate. Supplemental information from acn 786576: there are 2 approach and departure paths to the area. I chose the path that was the narrowest; trees on either side; but provided the best route for the wind conditions. The PIC agreed. The PNF stated 3 times: 'you have plenty of room here.' I flew too close to the trees on my right. I felt a slight vibration in the helicopter and said 'what was that?' the other pilot stated 'you hit the tree.' the vibration was very short and I continued to an uneventful landing.
Original NASA ASRS Text
Title: S76 HELI ON APPROACH TO A PRIVATE HELIPAD STRIKES A TREE; DAMAGING TWO ROTOR BLADES.
Narrative: DURING SHORT FINAL TO A PVT HELIPAD; THE HELI MAIN ROTOR STRUCK A TREE BRANCH. THE HELI WAS DECELERATING FOR THE LNDG AND WAS AT 70 FT AGL AND 40 KIAS AT THE TIME OF THE OCCURRENCE. I WAS THE PIC AND PNF IN THE L SEAT. MONITORING INSTS; I MADE THE '70 AGL/40 KIAS PLENTY OF CLRNC ON THE L' CALLOUT JUST PRIOR TO THE HELI ROTOR STRIKING THE TREE BRANCH. THE SIC WAS THE PF FROM THE R SEAT. SURFACE WINDS WERE RPTED 280 DEGS AT 9 KTS. APCH COURSE WAS 040 DEGS. THE L XWIND AND RESULTING L WIND CORRECTION ANGLE GAVE THE R SEAT PLT THE BEST VISUAL CUES FOR THE APCH FLOWN. THERE WAS ONLY A MOMENTARY FAINT SOUND AND VIBRATION AT THE TIME OF THE STRIKE AND NO OTHER UNUSUAL SOUNDS OR VIBRATIONS AS THE APCH WAS TO A HOVER AND NORMAL LNDG WITHIN 1 MIN OF THE STRIKE. THE ACFT WAS SHUT DOWN AFTER THE LNDG AT THE HELIPAD AND INSPECTION REVEALED 2 OF THE 4 MAIN ROTOR TIP CAPS WERE DAMAGED. THERE WERE NO INJURIES TO ANY OF THE 3 PAX OR 2 CREW MEMBERS. 2 OF THE PAX LATER STATED THAT THEY WERE NOT EVEN AWARE OF THE EVENT AT THE TIME IT HAPPENED. THE S76 HELI INST PANEL AND GLARE SHIELD CONFIGN IS POORLY DESIGNED IN RELATION TO MOST PLT SEAT POS THAT RESULT IN A COMPROMISE BTWN FORWARD VISIBILITY OVER THE NOSE OF THE HELI UP TO ABOUT 8 DEGS POSITIVE PITCH AND STILL BEING ABLE TO VIEW THE UPPER PORTION OF THE INST PANEL. FINAL APCH ATTITUDES ARE TYPICALLY 12 DEGS DURING DECELERATION AND 8 DEGS FOR HOVER. IN ORDER TO MAINTAIN A FULL VIEW OF THE APCH PATH AND LNDG AREA; THE PF WILL NORMALLY 'KICK' THE HELI OUT OF TRIM AND OBTAIN A FULL VIEW PAST THE SIDE OF THE GLARE SHIELD; LOOKING THROUGH THE WINDSHIELD AND 'CHIN BUBBLE' IF NECESSARY. EACH PLT'S LATERAL VIEW OPPOSITE THEIR SEAT POS IS ALMOST NIL DURING THE DECELERATION ATTITUDE. THE PLT FLYING AN APCH TO A CONFINED HELIPAD MUST RELY ON CLRNC CALLOUTS FROM THE PNF. SOME OF THE NEWER MODEL HELIS HAVE GLARE SHIELDS THAT WILL SLIDE FORE AND AFT TO MEET THE ERGONOMIC NEEDS OF THE PLT. WE WILL LOOK INTO THE AVAILABILITY OF A MODIFICATION FOR OUR HELI. THE PLTS FLYING THIS HELI HAVE CONSIDERABLE EXPERIENCE. WE WILL REVIEW OUR CRITERIA FOR UTILIZING THIS APCH AND THE PROC FOR ITS USE. WE CAN CERTAINLY DEVELOP SIMULATOR TRAINING PROFILES FOR NEWLY ESTABLISHED PROCS. WE MAY ABANDON THIS APCH IF APPROPRIATE. SUPPLEMENTAL INFO FROM ACN 786576: THERE ARE 2 APCH AND DEP PATHS TO THE AREA. I CHOSE THE PATH THAT WAS THE NARROWEST; TREES ON EITHER SIDE; BUT PROVIDED THE BEST RTE FOR THE WIND CONDITIONS. THE PIC AGREED. THE PNF STATED 3 TIMES: 'YOU HAVE PLENTY OF ROOM HERE.' I FLEW TOO CLOSE TO THE TREES ON MY R. I FELT A SLIGHT VIBRATION IN THE HELI AND SAID 'WHAT WAS THAT?' THE OTHER PLT STATED 'YOU HIT THE TREE.' THE VIBRATION WAS VERY SHORT AND I CONTINUED TO AN UNEVENTFUL LNDG.
Data retrieved from NASA's ASRS site as of May 2009 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.