What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
N647C departed lily lake, amphibious runway located on kgpz, Grand Rapids Airport. Pic's intent was to fly 4 miles to the south and practice landings on lake pokegama. This airplane had not been flown in over a year because it was going through a foreign to U.S.. Conformity inspection. An annual inspection had been completed, the last oil change was performed in 2017, and the fuel was a mix of fresh avgas and auto fuel over a year old. The PIC departed to the nw and immediately turned south as planned. .4 NM approximately 30 seconds in the climb the PIC experienced a partial power loss at about 400 ft AGL. The PIC immediately turned east inside the field boundary with the intent to set up left downwind, left base and land back on lily lake. A ground witness stated that the plane was higher than normal at the abeam and after the PIC started to make the left turn to final, he made a 360 degree left turn. PIC states that in the turn the engine drops to 17-18 inches, a throttle pump gives brief power burst, shortly thereafter, two pops and the engine dies. Then on the farthest east part of that turn the plane disappeared in the water plant, then the tail was seen high in the air cart wheeling. The PIC confirmed that he was high on his turn to final and made a turn to extend his downwind. Before that additional turning maneuver the plane had been flying with a partial power loss for approximately 30 seconds. If the approach to land had been continued the plane should have touched down in another 30 seconds with a reduced power setting for the landing. However, the additional turn maneuver added approximately 45-80 seconds of additional flight at a higher power setting, and at half way through the 360 degree turn a complete power loss was experienced. This happened at the moment the aircraft was at it's farthest point east of the field and outside of the field boundary. Analyzing the time and space, had the airplane been flown at an appropriate altitude and pattern there would have been enough engine power and time to execute a partial power loss precautionary emergency landing. To the question of trouble shooting airborne the pilot responded he was performing a little trouble shooting.
As the FAA filed it
N647C DEPARTED LILY LAKE, AMPHIBIOUS RUNWAY LOCATED ON KGPZ, GRAND RAPIDS AIRPORT. PIC'S INTENT WAS TO FLY 4 MILES TO THE SOUTH AND PRACTICE LANDINGS ON LAKE POKEGAMA. THIS AIRPLANE HAD NOT BEEN FLOWN IN OVER A YEAR BECAUSE IT WAS GOING THROUGH A FOREIGN TO U.S.. CONFORMITY INSPECTION. AN ANNUAL INSPECTION HAD BEEN COMPLETED, THE LAST OIL CHANGE WAS PERFORMED IN 2017, AND THE FUEL WAS A MIX OF FRESH AVGAS AND AUTO FUEL OVER A YEAR OLD. THE PIC DEPARTED TO THE NW AND IMMEDIATELY TURNED SOUTH AS PLANNED. .4 NM APPROXIMATELY 30 SECONDS IN THE CLIMB THE PIC EXPERIENCED A PARTIAL POWER LOSS AT ABOUT 400 FT AGL. THE PIC IMMEDIATELY TURNED EAST INSIDE THE FIELD BOUNDARY WITH THE INTENT TO SET UP LEFT DOWNWIND, LEFT BASE AND LAND BACK ON LILY LAKE. A GROUND WITNESS STATED THAT THE PLANE WAS HIGHER THAN NORMAL AT THE ABEAM AND AFTER THE PIC STARTED TO MAKE THE LEFT TURN TO FINAL, HE MADE A 360 DEGREE LEFT TURN. PIC STATES THAT IN THE TURN THE ENGINE DROPS TO 17-18 INCHES, A THROTTLE PUMP GIVES BRIEF POWER BURST, SHORTLY THEREAFTER, TWO POPS AND THE ENGINE DIES. THEN ON THE FARTHEST EAST PART OF THAT TURN THE PLANE DISAPPEARED IN THE WATER PLANT, THEN THE TAIL WAS SEEN HIGH IN THE AIR CART WHEELING. THE PIC CONFIRMED THAT HE WAS HIGH ON HIS TURN TO FINAL AND MADE A TURN TO EXTEND HIS DOWNWIND. BEFORE THAT ADDITIONAL TURNING MANEUVER THE PLANE HAD BEEN FLYING WITH A PARTIAL POWER LOSS FOR APPROXIMATELY 30 SECONDS. IF THE APPROACH TO LAND HAD BEEN CONTINUED THE PLANE SHOULD HAVE TOUCHED DOWN IN ANOTHER 30 SECONDS WITH A REDUCED POWER SETTING FOR THE LANDING. HOWEVER, THE ADDITIONAL TURN MANEUVER ADDED APPROXIMATELY 45-80 SECONDS OF ADDITIONAL FLIGHT AT A HIGHER POWER SETTING, AND AT HALF WAY THROUGH THE 360 DEGREE TURN A COMPLETE POWER LOSS WAS EXPERIENCED. THIS HAPPENED AT THE MOMENT THE AIRCRAFT WAS AT IT'S FARTHEST POINT EAST OF THE FIELD AND OUTSIDE OF THE FIELD BOUNDARY. ANALYZING THE TIME AND SPACE, HAD THE AIRPLANE BEEN FLOWN AT AN APPROPRIATE ALTITUDE AND PATTERN THERE WOULD HAVE BEEN ENOUGH ENGINE POWER AND TIME TO EXECUTE A PARTIAL POWER LOSS PRECAUTIONARY EMERGENCY LANDING. TO THE QUESTION OF TROUBLE SHOOTING AIRBORNE THE PILOT RESPONDED HE WAS PERFORMING A LITTLE TROUBLE SHOOTING.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.