WPR11GA115

An inadvertent tail rotor strike during an attempted pinnacle landing, which resulted in the pilot's loss of control of the helicopter. Inhospitable terrain/topography contributed to the severity of the accident.

The four-place, turbine-powered helicopter was being operated by the county sheriff's department in support of a county emergency communications system development and construction project. The accident flight was intended to enable technical personnel to conduct a site survey for the planned installation of a communications repeater tower near the top of a mountain. The sheriff's department pilot had satisfactorily completed training for and had demonstrated confined area, slope, and pinnacle landings. None of the three passengers were helicopter pilots, and no anti-torque pedals were installed at the front passenger's station. The mountain's remote location and its topography prevented postaccident availability of specific meteorological conditions at the time of the accident, but analysis of available data indicated that mostly overcast skies, intermittent rain, and a generally westerly wind at 10 to 15 knots were present. Those conditions were within the helicopter's and pilot's performance capabilities. The helicopter orbited the peak for general reconnoitering before the pilot attempted a landing. The pilot's selected landing zone was on a relatively level area of a pinnacle on the northeast side of the mountain, and the approach was from the southeast. The passengers reported that during the landing attempt, they felt a bump, and the helicopter rose a few feet, then the nose pitched down, and the helicopter began to spin to the right. The main rotor blades struck a rock outcrop, and the helicopter tumbled and slid about 120 feet down a shallow canyon on the northeast face of the peak before it was halted by rocks and scrub vegetation. The wreckage was examined in situ, recovered, and examined in detail. All components were accounted for. All damage patterns were consistent with the helicopter's low-speed impact with terrain in the horizontal and vertical planes, and its subsequent tumble down the canyon. The engine successfully met specification power settings during an operational run in a test fixture. No evidence of any preexisting mechanical defect or malfunction was noted during the examination or testing of the airframe and engine. Main and tail rotor damage patterns and debris distribution were consistent with rotor strikes under power. The witness and passenger descriptions of the helicopter's motions are consistent with a tail rotor ground strike and a subsequent loss of directional control. Although no reliable ground scars indicative of a tail rotor strike were found, that was likely precluded by the rocky, hard surface of the landing zone.

HISTORY OF FLIGHT On January 31, 2011, about 1115 mountain standard time, a McDonnell-Douglas 369FF helicopter, N530RL, was substantially damaged during an attempted pinnacle landing on Waterman Peak near Marana, Arizona. The pilot received fatal injuries, two passengers received serious injuries, and one passenger received minor injuries. The public-use flight was operated by the Pima County Sheriff's Department (PCSD) in support of the Pima County Wireless Integrated Network (PCWIN) communications development project. Visual meteorological conditions prevailed, and no flight plan was filed for the flight. The purpose of the flight was to enable PCWIN personnel to conduct a site survey for the planned installation of a communications repeater tower. The helicopter departed Tucson International Airport (TUS), Tucson, Arizona, about 1050, with the PCSD pilot in the left front seat, two Pima County employees in the right front and rear seats, and a private contractor in the left rear seat. Initially, the flight was in communication with, and being tracked by, TUS local and TRACON air traffic control (ATC) facilities as it headed for the peak, located about 30 miles west-northwest of TUS. Communications were intentionally terminated by the helicopter once it was well clear of TUS airspace. The helicopter orbited Waterman Peak counterclockwise approximately twice, for general reconnoitering, before the attempted landing. The pilot's selected landing zone (LZ) was on a relatively level area of a pinnacle on the northeast side of the mountain. The approach was from the southeast. The passengers reported that during the landing attempt they felt a "bump"; the helicopter then either bounced or the pilot lifted off again, the nose pitched down, and the helicopter began to spin to the right. A ground-based witness located about 1,000 feet west of and below the LZ stated that the helicopter completed about four or five rotations before it disappeared from his view. The main rotor blades struck a rock outcrop northeast of the LZ, and the helicopter then tumbled and slid about 120 feet down a shallow canyon on the northeast face of the peak before it was halted by rocks and scrub vegetation. Two passengers used their mobile phones to call 911 for assistance. PCSD, US Customs and Border Protection, Arizona Department of Public Safety, and US military equipment and personnel participated in the victim rescue and recovery. PERSONNEL INFORMATION Federal Aviation Administration (FAA) records indicated that the pilot held a commercial pilot certificate with rotorcraft-helicopter and instrument-helicopter ratings, and a private pilot certificate with airplane single and multi-engine land ratings. According to the pilot's personal flight log, he had approximately 11,500 total hours of flight experience, most of which was in helicopters. His first recorded flight in the accident helicopter make and model was in August 2008, and he had logged about 186 total hours in that equipment. In January 2011, excluding the accident flight, the pilot logged 6 flights, for a total of 7.5 hours, in the accident helicopter make and model. His most recent FAA second-class medical certificate was issued in February 2010. According to PCSD information, the pilot joined PCSD in November 2008, and had about 30 years experience flying helicopters for the Arizona Department of Public Safety and the Maricopa County Sheriff's Department. PCSD records indicated that he had satisfactorily completed training for and demonstration of confined area, slope, and pinnacle landings. The Pima County Office of the Medical Examiner autopsy report indicated that the cause of death was "multiple blunt force injuries." Both Pima County and the FAA Civil Aeromedical Institute reported that forensic toxicology examinations on specimens from the pilot revealed that no carbon monoxide, cyanide, ethanol, or any other screened drugs were detected. AIRCRAFT INFORMATION The helicopter was manufactured new in 1985 as a Hughes model 369E, serial number 0128E. In September 1998 it was converted to a McDonnell Douglas model 369FF, serial number 0602FF, by McDonnell Douglas Helicopter, Incorporated. The helicopter was equipped with an Allison (Rolls-Royce) 250-C30 series turbine engine. It was registered to Pima County in 2008. The helicopter was left-seat command with dual controls, but the right-seat pedals were not installed for the accident flight. The most recent 100-hour and annual maintenance inspections were completed on April 13, 2010, when the helicopter had a total time in service (TT) of 3,626.9 hours. At the time of the accident the helicopter had a TT of 3,740.3 hours. Review of the maintenance records indicated that the helicopter was in compliance with all applicable Service Bulletins and Airworthiness Directives. Weight and balance calculations indicated that the helicopter was within its certificated weight and balance envelope for the flight. Fueling records indicated that the helicopter was serviced with the proper fuel, and had sufficient fuel on board for the flight. METEOROLOGICAL INFORMATION About the time of the accident, there were two low pressure systems to the east, and a high pressure system to the northwest. No defined system surface boundaries were identified in the vicinity of the accident site. The station models surrounding the accident site indicated a general westerly wind at approximately 10 knots, with winds varying from the west-southwest to the west-northwest; scattered clouds; temperatures about 10 to 14 degrees C; and dew point about 0 to 4 degrees C. A National Weather Service (NWS) Convective Outlook forecast issued about 2 hours before the accident included a risk of general air mass type thunderstorms over eastern Arizona The weather observation station closest to the accident site was located 19 miles southeast of the accident site, at an elevation of 2,417 feet. About 30 minutes before the accident, the station winds were from 090 degrees at 11 knots, with gusts to 16 knots. About the time of the accident, conditions included visibility 10 miles, and few clouds between 5,500 and 7,500 feet. About 30 minutes before the accident, the next closest station, located approximately 30 miles southeast of the accident site, at an elevation of 2,643 feet, reported winds from 300 degrees at 9 knots, with gusts to 16 knots; visibility 10 miles, a ceiling of broken clouds at 7,000 feet; temperature 12 degrees C; and dew point 1degree C. One hour later, that station observation included wind gusts to 24 knots. The Geostationary Operational Environmental Satellite number 11 (GOES-11) visible image for 1100 depicted the accident site under the western portion of a band of clouds, with several embedded cumulus congestus type clouds in the larger stratocumulus cloud layer. The infrared image for the same period depicted cloud tops of 17,500 feet over the accident site. The 1130 GOES-11 visible image showed the band of clouds had moved eastward, with several well defined cumulus congestus to cumulonimbus cloud tops immediately downwind (east) of the accident site. There was an abrupt clearing of the clouds in the vicinity of the accident site, but nearby cloud formations indicated surface winds from the north. The closest NWS Doppler Weather Surveillance radar was too far away to provide accident site wind data. The NWS issued in-flight weather advisories (in order of decreasing severity) designated as Convective SIGMETs, SIGMETs, and AIRMETs to notify pilots of the possibility of hazardous weather conditions. No Convective SIGMETs were current for the flight. An AIRMET Tango for moderate turbulence below 15,000 feet and an AIRMET Zulu for moderate icing between the freezing level and 18,000 feet were current for the flight. Witness reports indicated that about the time of the accident, the mountain was visible below an