Accident Overview
On August 31, 2014, about 1800 Alaska daylight time, a de Havilland DHC-2 "Beaver" airplane, registration N93E, was substantially damaged during a collision with trees and terrain. The accident occurred following a loss of engine power during takeoff from Lake Hood Strip, Anchorage, Alaska. The flight was being operated as a visual flight rules (VFR) personal flight under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the intended destination, a hunting camp approximately 30 miles west of Anchorage.
Of the four people on board, one passenger received minor injuries, while the private pilot and two additional passengers were not injured.
Pilot's Account
In a written statement to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), the pilot reported that he was making a second trip to camp that day. After takeoff, at an altitude of about 100 feet above ground level, the engine lost power. The pilot unsuccessfully attempted to restart the engine and performed a forced landing in an area of densely populated spruce trees. During the forced landing, the airplane sustained substantial damage to the fuselage, wings, and horizontal stabilizer.
Post-Accident Examination
The engine and airframe were examined by the NTSB IIC on September 4 at the facilities of Alaska Aircraft Sales. No airframe anomalies were noted that would have precluded normal operation. The engine was inspected, and all internal components were intact and functional. The magnetos, carburetor, and engine-driven fuel pump were removed for further examination.
On December 4 and January 14, 2015, the NTSB IIC, along with another NTSB investigator, examined the removed engine accessories at the facilities of Alaskan Aircraft Engines. The magnetos and carburetor were tested with no anomalies noted. The engine-driven fuel pump was tested on two separate test benches and run through a variety of RPM, fuel flow, and fuel pressure tests. Fuel flow results from the various tests revealed widely inconsistent flow rates under the same test conditions. A control fuel pump was also tested on the same equipment, with consistent results in fuel flow.
The pump was disassembled, and several anomalies were noted. The spline driver oil seal on the spline driver shaft was split and was protruding through the opening in the spline driver thrust washer. The engine oil seal was not found inside the pump. It is unknown if the engine oil seal was installed or if the ring itself deteriorated inside the housing. The overall appearance of the seal housing and pump bearings was dirty, and numerous pieces of foreign matter were noted within the seal and pump housing.
The fuel pump had been installed on the airplane on November 1, 2000, and the engine had accrued about 520 hours of operation since installation.