Accident Details
On October 2, 2021, at about 1646 Pacific daylight time, an amateur-built Zenith CH750 airplane, registration N99HX, was substantially damaged when it was involved in an accident near the Fairways Airport in Oregon City, Oregon. The pilot was not injured, and the passenger sustained minor injuries. The airplane was operating as a Title 14 Code of Federal Regulations Part 91 personal flight.
Pilot Report
The pilot reported that he departed about an hour before the accident. Following an uneventful local flight, he entered the airport traffic pattern on left downwind for runway 32. After turning onto final approach, the passenger told him she smelled something burning, and shortly after, the pilot also noticed the smell. A few moments later, the sound of the engine changed for about 5 seconds, followed by a total loss of engine power. The pilot realized he could not make it to the airport and initiated an off-airport landing between two tall trees. During the landing sequence, the airplane impacted trees and terrain, nosed over, and came to rest inverted. This resulted in substantial damage to both wings. Following the accident, the pilot reported that the right fuel tank appeared to be empty and that some fuel was leaking slightly from the left wing fuel tank.
The pilot reported that before the flight, he refueled the left wing with 4 gallons of automotive fuel. After refueling, the left wing contained about 10 gallons of fuel, and the right wing contained about 3 gallons. When asked about verifying fuel levels, the pilot stated that he measured the right fuel tank using the electronic flight information system and did not dip the tank. He said the left fuel tank was right between 3 and 4 gallons before he added fuel, and after fueling the left wing, it was at 7 gallons dipped via a dip stick. The pilot reiterated that it was 7 gallons when he finished refueling and that the fuel burn rate was about 4.3 gallons per hour. On the Pilot/Operator Aircraft Accident Report Form, the pilot reported that the airplane had 10 to 11 gallons of fuel at takeoff.
Postaccident Examination
Postaccident examination of the recovered airplane revealed that the fuel valves between the header tank and the wings were in the off position, and the fuel valve from the header tank to the electronic fuel pump was in the on position. The header fuel tank was void of any fuel. About a teaspoon of fuel was removed from the mechanical fuel pump. When the electric fuel pump was turned on, it emitted a loud audible noise consistent with operating with no liquid (cavitating). No fuel was observed within either carburetor float bowl. The engine was test run for several seconds uneventfully. No evidence of any preexisting mechanical malfunctions was observed with the recovered engine or airframe.
Aircraft Information
The airplane was equipped with two wing fuel tanks (left and right) with a total capacity of 24 gallons of fuel, of which 22 gallons is usable. In addition, the airplane was equipped with a 1.6-gallon header tank.