Accident Details
Probable Cause and Findings
The pilot's improper engine modification and operation, which resulted in a total loss of engine power due to fuel starvation, and the pilot's failure to maintain an adequate approach path, which resulted in the airplane landing short of the runway.
Aircraft Information
Registered Owner (Historical)
Analysis
The pilot of the tailwheel-equipped, experimental amateur built airplane, who was also an airframe and powerplant mechanic reported that, during approach to a sandbar, he side-slipped the airplane and the engine lost power because he was "too aggressive with the throttle and pulled it enough to bend the [carburetor] idle stop screw bracket." Because the engine was normally quiet, the airplane was sound proofed, and he used a noise-cancelling headset, he was unaware of the power loss until he attempted to add power, to no avail. He did not have enough time to restart the engine, so the airplane settled onto the water about 15 to 20 ft short of the sandbar. Subsequently, the airplane hydroplaned and came to rest on the sandbar inverted.
The pilot reported that the reason he was aggressive with the throttle was because of a lean mixture that tended to overheat the engine during takeoff or cruise on hot days.
Previously, he had attempted to mechanically enrichen the mixture by drilling holes in the fuel spray bar, but had drilled a hole "at the location where the engine wanted to idle", meaning that if the hole was open, the engine would idle high and if the hole was closed, the engine would "die." He added that it was not a problem unless he was trying to land short.
The airplane sustained substantial damage to the left wing lift strut, left wing, and rudder.
The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.
The Federal Aviation Administration (FAA) inspector reported that the pilot had modified the number and position of the last hole in the fuel spray bar. By doing so, the pilot was able to get the engine to "barely run" to perform short field landings. During the accident landing, it "must have cut off the flow of fuel enough to make the engine quit."
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# GAA19CA034