NTSB Factual Report

HISTORY OF FLIGHT

On August 1, 2014, about 0900 Pacific daylight time, a Schweizer Aircraft Corporation G-164B, N3627R, impacted terrain after striking a set of power distribution lines near Tulelake, California. The airplane was registered to, and operated by, Macy's Flying Service as an aerial application flight under the provisions of 14 Code of Federal Regulations Part 137. The commercial pilot was fatally injured; the airplane sustained substantial damage during the accident sequence, and was subsequently destroyed by post impact fire. The local flight departed Tulelake Municipal Airport about 0820. Visual meteorological conditions prevailed, and no flight plan had been filed.

Officers from the Siskiyou County Sheriff's Department responded to the accident site, and observed the airplane located in an alfalfa field, 500 ft north of a series of severed overhead power distribution lines. The airplane came to rest on a south heading, and the cabin had been consumed by fire after sustaining extensive crush damage. All four wings had become partially detached from the airframe, and the left top wing was folded up over the vertical stabilizer.

The pilot was applying insecticide to an alfalfa field, and the accident occurred on one of the last passes.

PERSONNEL INFORMATION

The 58-year-old-pilot held a commercial pilot certificate with ratings for airplane single-engine land, and instrument airplane. He was issued a second-class medical certificate on September 7, 2013, with limitations that he must wear corrective lenses. On his medical certificate application, he reported a total flight time of 30,000 hours. The operator reported that the pilot had flown 504 hours in the accident airplane in the 90 days preceding the accident.

AIRPLANE INFORMATION

The tailwheel-equipped airplane was manufactured in 1983, as a restricted agriculture and pest control category biplane. It was configured for aerial application and equipped with a 715 shaft horsepower Garrett/Airesearch TPE331-2 turboprop engine, driving a three blade controllable pitch Hartzell propeller.

The airplane's height was 10 ft, 9 inches.

METEOROLOGICAL INFORMATION

An automated surface weather observation at Klamath Falls Airport, Klamath Falls, Oregon (elevation 4,095 feet msl, 14 miles northeast of accident site), was issued 7 minutes before the accident. It indicated calm wind, 10 miles or greater visibility, clear skies, temperature at 22 degrees C, dew point 10 degrees C, and an altimeter setting at 30.14 inches of mercury.

According to the U.S. Naval Observatory, Astronomical Applications Department, the altitude of the Sun when viewed from Tulelake at 0900 was 31.8 degrees, with an Azimuth (E of N) of 94.0 degrees.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was conducted by the County of Siskiyou Office of the Sheriff/Coroner. The cause of death was reported as thermal injury due to an airplane crash with an anatomic finding of soot in the larynx and trachea.

Toxicological tests on specimens recovered from the pilot were performed by the FAA Civil Aerospace Medical Institute. The results indicated 16 percent carbon monoxide detected in the blood, and were negative for all screened drug substances and ingested alcohol. Refer to the toxicology report included in the public docket for specific test parameters and results.

TESTS AND RESEARCH

Engine and Airframe Exam

The engine and airframe were recovered from the accident site, and examined by the NTSB investigator-in-charge. The empennage was intact, with the remaining airframe components displaying extensive fragmentation, thermal, and crush damage. The flight control system exhibited multiple breaches but was functionally intact. A 25-ft-long section of copper cable was found entwined in the leading edge of the upper right wing.

The engine had separated from its mount, and the gearbox had detached from the engine's forward section. The exhaust stack was still attached, and light brown sooting was present on its inner surface; there were no indications of cracks or indentations associated with internal engine blade liberation. The inlet compressor wheel was intact, could be rotated by hand, and moved smoothly with corresponding rotation of the forward accessory case gears. The propeller hub remained attached to the gearbox along with two propeller blades which both exhibited leading edge gouges, chordwise scratches, and twist throughout their entire length. The third blade was separated from the hub and exhibited similar damage.

Examination did not reveal any anomalies with the airframe or engine that would have precluded normal operation. A full report is contained within the public docket.

Power Lines

The power lines and poles were owned by Pacific Power of Portland, Oregon. The poles were about 40 ft tall, oriented east-west, and covered a span of 300 ft. A set of three high-voltage power transmission lines were strung at the top of each pole, with four thinner-gauge power distribution, "under-build" lines hanging below, 30 ft 6 inches from the ground. According to representatives from Pacific Power, the lower under-build lines had been severed about 50 ft east of the west pole, and the higher power transmission lines were undamaged.

A spotter had been assigned to the pilot; however, he did not witness the accident, and was transitioning to another location at the time. According to the operator the pilot was familiar with the field, had flown under the lines many times before, and most likely made the decision to fly under because they were very high relative to the field location.

FAA regulations allow pilots of agricultural aircraft flexibility with the regard to obstacle clearances, specifically, Part 137.29, Subpart C states, "The holder of an agricultural aircraft operator certificate may deviate from the provisions of part 91 of this chapter without a certificate of waiver, as authorized in this subpart for dispensing operations, when conducting nondispensing aerial work operations related to agriculture, horticulture, or forest preservation in accordance with the operating rules of this subpart."

Furthermore, Advisory Circular AC 137-1A for agricultural operators gives specific guidance for flying in various conditions, including when it is necessary to fly under wires.

NTSB Probable Cause

The pilot's failure to maintain clearance from power lines while maneuvering during low-altitude operations.