History of Flight
On June 30, 2012, at 1207 Pacific daylight time, a Eurocopter AS350BA, registration N729DP, was flying low through the Verde River canyon approximately 8.6 miles south of Camp Verde, Arizona, when it struck a cable that spanned the river at a narrow portion of the canyon. The helicopter was operated by a private pilot under Part 91. The pilot and three passengers were fatally injured, and the helicopter was substantially damaged. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Scottsdale Airport around 0825.
The helicopter was reported missing on June 30 by family members, and the wreckage was located on July 1. It was lying on its right side in 4-5 feet of water in the center of the Verde River. Vertical cliffs about 200 feet high flanked both sides of the river. Approximately 300 feet north of the wreckage, a USGS streamgaging cableway system spanned the river, elevated 39 feet above the water. The steel cable was found severed, with the cable carriage on the landing platform deformed. The cable ends were flayed consistent with overload, and the eastern cable end had grey paint matching the color of the rotor blades, with composite rotor blade fibers embedded in the strands.
Radar records and mobile phone location data tracked the helicopter's route. A park ranger at Montezuma Castle National Monument reported seeing the helicopter at low altitude around 1155 before it departed toward Camp Verde. The last phone activity was recorded at 1207 near the accident location.
Aircraft and Pilot Information
The five-seat, single-engine helicopter, serial number 2338, was manufactured in 1990. It was powered by a Turbomeca Arriel 1B engine. An annual inspection was completed on February 10, 2012, at a total aircraft time of 7,342.4 hours. The most recent maintenance included air conditioning system work and a tail boom torque check on June 25, 2012.
The 70-year-old pilot held a private pilot certificate with ratings for airplane single- and multiengine land, instrument airplane, and rotorcraft-helicopter. He had a third-class special issuance medical certificate requiring glasses for near vision. He reported 4,500 total flight hours on his medical application, with 1,734.2 hours of helicopter time and 416.9 hours in the AS350 model. His most recent flight review was on March 28, 2011. No flight time was recorded in the 90 days preceding the accident.
Wreckage and Impact Information
The helicopter came to rest on its right side. The main rotor and transmission separated as a unit and were found approximately 70 feet east of the fuselage. The tail boom separated at the fuselage-tail splice. The main rotor blades remained attached to the hub, but the tips of the red and yellow blades had separated about 3 feet inboard. Both blades had witness marks on their leading edges consistent with steel cable impact. The transmission mounts had overload fractures. Flight control rods were continuous from the cockpit to the transmission deck, but some pitch change links showed separation or cable witness marks. The engine remained with the fuselage; it showed evidence of an over-torque condition consistent with being driven during main rotor impact.
The USGS cable was approximately 1 inch in diameter and 286 feet long. The severed ends were flayed and shiny. The eastern and western cable segments were about 130 and 140 feet long, respectively. A steel platform with an aluminum carriage on the western side was bent and deformed.
Pathological and Toxicological Information
An autopsy by the Yavapai County Medical Examiner determined the cause of death as blunt force injuries. Toxicology testing on the pilot found ethanol in heart (0.083 gm/dL), brain (0.046 gm/dL), and blood (0.043 gm/dL), as well as small amounts of n-butanol and n-propanol. Acetaminophen, metoprolol, and diphenhydramine were detected. The pilot had a history of coronary artery disease and underwent four-vessel bypass surgery in 2004. His medical certification was granted through December 31, 2012.
Additional Information
The accident occurred in a Special Conservation Area marked on the Phoenix Sectional Aeronautical Chart. FAA Advisory Circular 91-36 recommends that pilots avoid noise-sensitive areas or fly at least 2,000 feet above the highest terrain. Photographs taken well before the accident by the USGS showed that the cable was not visible against the background terrain of the river and rock canyon.