What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
N388RA a CH47D helicopter was found on the south bank of the salmon river perpendicular to the bank in about 7-10 feet of water. Access was limited due to the location on the opposite side of the river from the access road. During initial assessment a witness provided a video showing the aircraft entering the event that lead to the crash in the river. The video showed the aircraft enter a hover at approximately 300 ft with an easterly heading. The aircraft had a 200 foot long line and +/- 40 foot firefighting water bucket attached. The helicopter starts a left hand turn around its axis in a hover, nose dips and rate of turn increases and altitude decrease until contact with the river.
Initial site inspection was accomplish with support from local sheriff department and the use of their river jet boat. Personnel were ferried across the river. The nose of helicopter rested approximately 5 feet from the edge of the river bank. The aft pylon had substantial damage and was twisted 90 degrees to the right of the main fuselage and submerged under water except for the #1 engine. The upper fuselage appeared to be compressed with limited internal cabin space. The front main gear box and rotor system was still attached with all three main rotor blades exhibiting damage of impact under power. Two distinct corresponding earthen rotor blade impact marks present on the river bank. Debris field extended approximately 100 feet in the trees in a 180 degree circle from the aircraft.
On aircraft inspection was performed by a limited number NTSB invited parties due to the aircraft structural condition and sitting in the river. Hums usb memory stick found above water line and removed for down load. Drive shaft cowling opened and inspected. Drive line between fwd gear box and the combining gear box still connected with only the input coupling to the combining box pull out slightly due to the rotation of the aft pylon. Flight controls accessible with water level were inspected for continuity. Only observed anomaly was the aft rotor lct actuator case was cracked. Humms thumb drive removed for down load and analysis. Initial down load showed all sensor in the green (within limits)
Additional aircraft inspections with the aircraft in the water performed to try and preserve component position prior to aircraft extraction from the water with overhead cranes. Both engine electronic control units were removed for data analysis. #1 and #2 afcs computers were removed. #2 computer was under water and placed in a tub of water for preservation.
A flight control rod was found sheared between the #1 and #2 mixing units. High resolution pictures were taken of the rod ends and sent to NTSB metallurgist lab. Results provided the following day, showed the breakage was consistent with impact load forces.
Pilot currency and training records reviewed and found current and up to date.
Weather was reviewed from data provided from the usfs weather station located approximately 100 yards up river. Winds at or near the time of the accident were 2-7 mph with gust to 20 mph with temperatures at 96* f.aircraft maintenance records reviewed, inspections were current. Limited maintenance performed prior to the accident as the aircraft only had approximately 70 hours hobbs time since purchasing the aircraft. Exact time unknown as hobbs meter was smashed and unreadable post-accident.
Further inspection of the aircraft after recovery from the river showed no significant findings. Inspection was performed starting at the aft rotor flight controls, drivetrain and hydraulic systems and finished at the forward rotor and cockpit. Fuel and hydraulic filter visually inspected with no noticeable debris. Filters and a small fluid sample bagged for analysis. Honeywell accident inspector inspected both engine and determined both were under power at impact.
At this time no cause has been determined based on FAA 9 areas of responsibilities.
As the FAA filed it
N388RA A CH47D HELICOPTER WAS FOUND ON THE SOUTH BANK OF THE SALMON RIVER PERPENDICULAR TO THE BANK IN ABOUT 7-10 FEET OF WATER. ACCESS WAS LIMITED DUE TO THE LOCATION ON THE OPPOSITE SIDE OF THE RIVER FROM THE ACCESS ROAD. DURING INITIAL ASSESSMENT A WITNESS PROVIDED A VIDEO SHOWING THE AIRCRAFT ENTERING THE EVENT THAT LEAD TO THE CRASH IN THE RIVER. THE VIDEO SHOWED THE AIRCRAFT ENTER A HOVER AT APPROXIMATELY 300 FT WITH AN EASTERLY HEADING. THE AIRCRAFT HAD A 200 FOOT LONG LINE AND +/- 40 FOOT FIREFIGHTING WATER BUCKET ATTACHED. THE HELICOPTER STARTS A LEFT HAND TURN AROUND ITS AXIS IN A HOVER, NOSE DIPS AND RATE OF TURN INCREASES AND ALTITUDE DECREASE UNTIL CONTACT WITH THE RIVER.
INITIAL SITE INSPECTION WAS ACCOMPLISH WITH SUPPORT FROM LOCAL SHERIFF DEPARTMENT AND THE USE OF THEIR RIVER JET BOAT. PERSONNEL WERE FERRIED ACROSS THE RIVER. THE NOSE OF HELICOPTER RESTED APPROXIMATELY 5 FEET FROM THE EDGE OF THE RIVER BANK. THE AFT PYLON HAD SUBSTANTIAL DAMAGE AND WAS TWISTED 90 DEGREES TO THE RIGHT OF THE MAIN FUSELAGE AND SUBMERGED UNDER WATER EXCEPT FOR THE #1 ENGINE. THE UPPER FUSELAGE APPEARED TO BE COMPRESSED WITH LIMITED INTERNAL CABIN SPACE. THE FRONT MAIN GEAR BOX AND ROTOR SYSTEM WAS STILL ATTACHED WITH ALL THREE MAIN ROTOR BLADES EXHIBITING DAMAGE OF IMPACT UNDER POWER. TWO DISTINCT CORRESPONDING EARTHEN ROTOR BLADE IMPACT MARKS PRESENT ON THE RIVER BANK. DEBRIS FIELD EXTENDED APPROXIMATELY 100 FEET IN THE TREES IN A 180 DEGREE CIRCLE FROM THE AIRCRAFT.
ON AIRCRAFT INSPECTION WAS PERFORMED BY A LIMITED NUMBER NTSB INVITED PARTIES DUE TO THE AIRCRAFT STRUCTURAL CONDITION AND SITTING IN THE RIVER. HUMS USB MEMORY STICK FOUND ABOVE WATER LINE AND REMOVED FOR DOWN LOAD. DRIVE SHAFT COWLING OPENED AND INSPECTED. DRIVE LINE BETWEEN FWD GEAR BOX AND THE COMBINING GEAR BOX STILL CONNECTED WITH ONLY THE INPUT COUPLING TO THE COMBINING BOX PULL OUT SLIGHTLY DUE TO THE ROTATION OF THE AFT PYLON. FLIGHT CONTROLS ACCESSIBLE WITH WATER LEVEL WERE INSPECTED FOR CONTINUITY. ONLY OBSERVED ANOMALY WAS THE AFT ROTOR LCT ACTUATOR CASE WAS CRACKED. HUMMS THUMB DRIVE REMOVED FOR DOWN LOAD AND ANALYSIS. INITIAL DOWN LOAD SHOWED ALL SENSOR IN THE GREEN (WITHIN LIMITS)
ADDITIONAL AIRCRAFT INSPECTIONS WITH THE AIRCRAFT IN THE WATER PERFORMED TO TRY AND PRESERVE COMPONENT POSITION PRIOR TO AIRCRAFT EXTRACTION FROM THE WATER WITH OVERHEAD CRANES. BOTH ENGINE ELECTRONIC CONTROL UNITS WERE REMOVED FOR DATA ANALYSIS. #1 AND #2 AFCS COMPUTERS WERE REMOVED. #2 COMPUTER WAS UNDER WATER AND PLACED IN A TUB OF WATER FOR PRESERVATION.
A FLIGHT CONTROL ROD WAS FOUND SHEARED BETWEEN THE #1 AND #2 MIXING UNITS. HIGH RESOLUTION PICTURES WERE TAKEN OF THE ROD ENDS AND SENT TO NTSB METALLURGIST LAB. RESULTS PROVIDED THE FOLLOWING DAY, SHOWED THE BREAKAGE WAS CONSISTENT WITH IMPACT LOAD FORCES.
PILOT CURRENCY AND TRAINING RECORDS REVIEWED AND FOUND CURRENT AND UP TO DATE.
WEATHER WAS REVIEWED FROM DATA PROVIDED FROM THE USFS WEATHER STATION LOCATED APPROXIMATELY 100 YARDS UP RIVER. WINDS AT OR NEAR THE TIME OF THE ACCIDENT WERE 2-7 MPH WITH GUST TO 20 MPH WITH TEMPERATURES AT 96* F.AIRCRAFT MAINTENANCE RECORDS REVIEWED, INSPECTIONS WERE CURRENT. LIMITED MAINTENANCE PERFORMED PRIOR TO THE ACCIDENT AS THE AIRCRAFT ONLY HAD APPROXIMATELY 70 HOURS HOBBS TIME SINCE PURCHASING THE AIRCRAFT. EXACT TIME UNKNOWN AS HOBBS METER WAS SMASHED AND UNREADABLE POST-ACCIDENT.
FURTHER INSPECTION OF THE AIRCRAFT AFTER RECOVERY FROM THE RIVER SHOWED NO SIGNIFICANT FINDINGS. INSPECTION WAS PERFORMED STARTING AT THE AFT ROTOR FLIGHT CONTROLS, DRIVETRAIN AND HYDRAULIC SYSTEMS AND FINISHED AT THE FORWARD ROTOR AND COCKPIT. FUEL AND HYDRAULIC FILTER VISUALLY INSPECTED WITH NO NOTICEABLE DEBRIS. FILTERS AND A SMALL FLUID SAMPLE BAGGED FOR ANALYSIS. HONEYWELL ACCIDENT INSPECTOR INSPECTED BOTH ENGINE AND DETERMINED BOTH WERE UNDER POWER AT IMPACT.
AT THIS TIME NO CAUSE HAS BEEN DETERMINED BASED ON FAA 9 AREAS OF RESPONSIBILITIES.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.