Accident Summary
On April 8, 2014, at approximately 1720 mountain daylight time, an experimental Northwing Apache Sport weight-shift control trike, registration N58AS, was substantially damaged when it struck the ground while maneuvering near Brigham City, Utah. The aircraft was operated by the pilot under Title 14 Code of Federal Regulations Part 91. The private pilot, the sole occupant, sustained fatal injuries. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from the local area at an unknown time.
Witness Accounts
A witness located near the accident site observed the trike flying north at a low altitude. The witness reported that the trike turned sharply east, as if the pilot was seeking a landing area, but appeared to add power to avoid trees and turned south. The witness then stated that the trike turned north, with the impression that the pilot intended to land on a road south of a marina.
Other witnesses, driving north and south on Interstate 15, reported that the trike was traveling east as it approached two sets of high-tension power lines. The aircraft suddenly banked steeply to the left, and subsequently descended into terrain.
Aircraft Examination
Local law enforcement examined the wreckage, which came to rest on its left side on a road adjacent to the two sets of power lines. All major structural components were present at the site. The trike was recovered for further examination.
On April 10, 2014, National Transportation Safety Board (NTSB) investigators examined the trike. The forward wing joint was crushed aft and covered in dirt. The left wing leading edge displayed dirty span-wise scuff marks. Multiple structural and control tubes were buckled, fractured, or separated, with all fracture surfaces exhibiting angular and jagged characteristics. All observed cable separations were splayed.
The three-blade propeller showed severe damage. One blade was fractured about one-third of the span from the hub, bent aft 90 degrees, with a jagged angular fracture. This blade had chordwise striations and scuffed paint on the cambered side. The second blade was split mid-chord, with the back side peeled to the root. The third blade was split mid-chord but the halves remained in place; its outboard half showed chordwise striations and missing paint.
Engine and Systems Examination
The Rotax 582 engine (serial number 6141213) remained intact. Throttle control movement corresponded with the cockpit throttle lever. Manual rotation of the crankshaft through 360 degrees resulted in gearbox rotation. The fuel filter was clean, and the fuel tank was over half full with clear fluid free of debris.
Both carburetors were disassembled; their screens and bowls were clean and contained fluid. Water detection paste indicated no water. The composite floats were undamaged, and float arms moved freely. Upper chambers were unremarkable. Photos taken by a Federal Aviation Administration (FAA) inspector on April 9 confirmed that the carburetor vent lines were installed with slits as specified in the Rotax 582 Installation Manual.
Pilot Information
The pilot held a private pilot certificate with an airplane single-engine land rating issued on January 25, 1986. Logbook entries showed flights until September 1989, totaling 152.1 hours, of which 126.9 were pilot-in-command. In 2009, the pilot logged three introductory flights in a Gyrocopter (2.5 hours). An introductory flight in a weight-shift control trike occurred on September 8, 2012 (1 hour). Between December 10, 2013, and February 22, 2014, the pilot completed 18 flights (16 hours) in weight-shift trikes with an instructor. From March 8 to April 4, 2014, the pilot logged four flights (3.3 hours) in the accident trike.
An autopsy performed by the Utah State Medical Examiner on April 9 determined the cause of death as blunt force injuries. Toxicology tests conducted by the FAA's Civil Aeromedical Institute were negative for carbon monoxide, volatiles, and drugs.