What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) Helicopter was operating under a forest service contract performing external load work using a belly hook instead of a long line. The helicopter was operating out of a cargo loading area on the Usfs Graham airstrip. After dropping the second load and departing back to the loading area, the aircraft began to vibrate. The pilot could not find a suitable landing spot between the drop area and the landing site, so he flew the helicopter back to the cargo loading area (about 3.5 miles) and landed at the Graham strip. Post flight inspection revealed that the rotorblades had struck some object. In checking with ground personnel at the drop site it was discovered that the blades had struck a lodgepole pine of approximately one to two inches in diameter. The pilot stated that he may not have seen the tree because it blended in with the hazy conditions of the day.
As the FAA filed it
(-23) HELICOPTER WAS OPERATING UNDER A FOREST SERVICE CONTRACT PERFORMING EXTERNAL LOAD WORK USING A BELLY HOOK INSTEAD OF A LONG LINE. THE HELICOPTER WAS OPERATING OUT OF A CARGO LOADING AREA ON THE USFS GRAHAM AIRSTRIP. AFTER DROPPING THE SECOND LOAD AND DEPARTING BACK TO THE LOADING AREA, THE AIRCRAFT BEGAN TO VIBRATE. THE PILOT COULD NOT FIND A SUITABLE LANDING SPOT BETWEEN THE DROP AREA AND THE LANDING SITE, SO HE FLEW THE HELICOPTER BACK TO THE CARGO LOADING AREA (ABOUT 3.5 MILES) AND LANDED AT THE GRAHAM STRIP. POST FLIGHT INSPECTION REVEALED THAT THE ROTORBLADES HAD STRUCK SOME OBJECT. IN CHECKING WITH GROUND PERSONNEL AT THE DROP SITE IT WAS DISCOVERED THAT THE BLADES HAD STRUCK A LODGEPOLE PINE OF APPROXIMATELY ONE TO TWO INCHES IN DIAMETER. THE PILOT STATED THAT HE MAY NOT HAVE SEEN THE TREE BECAUSE IT BLENDED IN WITH THE HAZY CONDITIONS OF THE DAY.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.