20230805010539A

THE ENGINE HAD 1.3 HOURS SINCE REBUILD BY THE OEM. THE DOM REPORTED TROUBLE ATTAINING THE PROPER ENGINE PARAMETERS, REQUIRING 15-20 SEPARATE TEST RUNS TO CALIBRATE THE DIFFERENTIAL PRESSURES. THE DAY OF THE ACCIDENT JUST PRIOR TO THE CERTIFICATE HOLDER (CH) RELEASING THE AIRCRAFT FOR REVENUE SERVICE A MECHANIC WAS ADJUSTING THE PROPELLER GOVERNOR. HE WAS REDUCING THE MAX RPM TO MATCH THE ENGINES LIMITATIONS. HE HAD TO REMOVE THE ARM FROM THE GOVERNOR AND ADJUST IT A TOOTH TO REACH THE DESIRED POWER SETTING. WHILE THE MECHANIC WAS ADJUSTING/TESTING THE ENGINE HE WAS APPROACHED 3 TIMES IN A 30-MINUTE PERIOD BY MANAGEMENT PERSONNEL TO DETERMINE WHEN THE AIRCRAFT WOULD BE AVAILABLE FOR REVENUE SERVICE.

THE AIRCRAFT WAS LAST FUELED ON AUGUST 3RD WITH 42.5 GALLONS. ON A PREVIOUS FLIGHT THE DAY OF THE ACCIDENT, THE FUEL QUANTITY ON BOARD WAS REPORTED AS 25 LEFT AND 25 RIGHT, THIS FLIGHT LASTED APPROXIMATELY 0.7 HOURS. THE DAY OF THE FLIGHT, THE PIC VERBALIZED TO ^PRIVACY DATA OMITTED^ GROUND PERSONNEL THAT HE REQUIRED 36 GALLONS OF FUEL FOR THE FLIGHT 18L/18R. GROUND PERSONNEL DIPPED THE AIRCRAFT TANKS AND DETERMINED THAT THERE WAS APPROXIMATELY 10 GALLONS IN THE LEFT AND 26 IN THE RIGHT. GROUND PERSONNEL CONVEYED THE TOTAL FUEL QUANTITY ON BOARD TO THE PIC. THE PIC REPORTED DISTRACTIONS DURING HIS FLIGHT PREPARATIONS AND DID NOT PHYSICALLY CONFIRM THE QUANTITY AS IS REQUIRED BY THE ^PRIVACY DATA OMITTED^ FLIGHT OPERATIONS MANUAL(FOM). THE FLIGHT LOG COMPLETED BY THE PIC INDICATED THAT THE AIRCRAFT CONTAINED 17 LEFT AND 18 RIGHT PRIOR TO FLIGHT. THE PIC DISCLOSED THAT HE DID NOT COMPLETE THE AIRCRAFT FLIGHT LOG PRIOR TO THE FLIGHT, IT WAS COMPLETED AFTER THE ACCIDENT WHEN HE RETURNED TO SALMON ID, THIS IS CONTRARY TO ^PRIVACY DATA OMITTED^ FOM.

THE AIRCRAFT DEPARTED SALMON, ID ON AUGUST 5TH AT APPROXIMATELY 1600 ENROUTE TO BOISE, ID WITH 4 PASSENGERS. THE PIC REPORTED HE HAD TO DIVERT NORTH TO AVOID WEATHER, APPROXIMATELY 45 MINUTES INTO THE FLIGHT, THE ENGINE BEGAN SPUTTERING AND THE RPM DECREASED TO APPROXIMATELY 600 AS REPORTED BY A PASSENGER. THE PILOT REPORTED RPM AT 2800, MANIFOLD PRESSURE AND FUEL FLOW WERE NORMAL. HE REPORTED HE DID NOT HAVE ADEQUATE POWER TO MAINTAIN ALTITUDE.

THE PIC INITIATED A TURN TOWARDS INDIAN CREEK AIRSTRIP, WHICH THEY PASSED 10 MINUTES PRIOR. THE PIC BEGAN TO ADJUST FUEL MIXTURE AND THROTTLE SETTINGS. HE REPORTEDLY STATED “I HAVE NO THROTTLE”. ON DESCENT HE SWITCHED TANKS. ON FINAL APPROACH THE ENGINE REGAINED POWER, THE AIRCRAFT GAINED 80-100 FT OF ALTITUDE. THE PIC ELECTED TO CONTINUE THE LANDING, GEAR UP DUE TO A HIGH APPROACH SPEED AND FEAR OF OVERRUNNING THE RUNWAY. THE AIRCRAFT LANDED AND CAME TO A REST IN THE MIDDLE OF INDIAN CREEK FORREST SERVICE AIRSTRIP (S81).

THE PASSENGERS AND THE PIC WERE UNINJURED OTHER THAN, ALL PASSENGER’S REPORTED MUSCLE SORENESS, ONE WAS EXAMINED AT A HOSPITAL THE NEXT DAY AND RELEASED WITH NO SIGNIFICANT FINDINGS.

THE AIRCRAFT WAS AIRLIFTED TO LANDMARK AIRSTRIP (0U0). THE ELEVATORS, HORIZONTAL STABILIZER AND FLAPS WERE DAMAGED FROM THE LIFTING STRAPS. THE FRONT LOWER FUSELAGE BULKHEAD WAS DAMAGED DURING THE ACCIDENT. THE PROPELLER WAS DAMAGED INDICATING THE ENGINE WAS PRODUCING POWER AT THE TIME OF IMPACT. THE LEFT TANK HAD ZERO FUEL, THE RIGHT HAD 18 GALLONS +/-. THERE WAS STREAKING ON THE RIGHT-HAND SIDE OF THE FUSELAGE AFT OF THE ENGINE COWL. A LIMITED EXAMINATION OF THE ENGINE FOUND THE UPPER DECK PRESSURE DISTRIBUTION BLOCK HAD A LOOSE LINE GOING THROUGH THE FIREWALL TO THE FUEL FLOW GAUGE. AN EXAMINATION OF THE HEADER TANKS FOUND THE RIGHT APPEARED FULL, THE LEFT HAD A LESSER AMOUNT, THIS WAS DETERMINED BY THE RATE OF FLOW OUT OF THE TANK SUMP DRAIN. THE QUANTITIES COULD NOT BE DETERMINED DUE TO LIMITED EQUIPMENT. LACK OF RESOURCES PREVENTED AN EXAMINATION OF THE PROPELLER GOVERNORS’ CONDITION AND SUBSEQUENT RIGGING, THE CONDITION OF THE FUEL SELECTOR VALVE TO DETERMINE IT’S STATE RELATIVE TO WEAR/DETERIORATION, THE CONDITION OF THE FUEL PUMP AND POWER OUTPUT OF THE ENGINE.