What happened
Prior to departing Alpine Airport, the pilot completed an abbreviated preflight inspection with both the main and auxiliary fuel tanks filled. An engine run-up was not conducted before takeoff. During the climb, at approximately 100 feet above ground level, the left engine began to surge. Recognizing that the aircraft lacked the performance to maintain altitude at the airport's elevation with one engine inoperative, the pilot attempted to address the issue by switching the left engine's boost pump from the low to the high position. Despite this action, the engine continued to surge, causing the aircraft to lose altitude.
The pilot executed a forced landing with the flaps and landing gear retracted and the left propeller in an unfeathered state. The aircraft type impacted the terrain with the left wing tip first, resulting in a post-impact fire that damaged the left side of the fuselage and the left wing. There were 0 fatalities and 0 injuries reported in the accident.
Findings
Investigations revealed that the aircraft's takeoff weight was 6,509 pounds, which exceeded the maximum takeoff weight of 6,350 pounds. The left engine's spark plugs were heavily coated in black soot. Examination of the magnetos showed that the left magneto failed to produce a spark, while the right magneto only functioned on three of its six distributor cap posts. Furthermore, the primary winding resistance and capacitor leakage of the left magneto were outside of manufacturer specifications, and both magnetos contained internal oil and debris.
A critical factor involved the use of the auxiliary fuel pump; the pilot's manual warns that placing the auxiliary pump in the high position while the engine-driven pump is functioning normally can lead to a total loss of engine power. The improper use of the auxiliary fuel pump was a significant element in the engine's failure.