Accident Details
Probable Cause and Findings
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.
Aircraft Information
Registered Owner (Current)
Analysis
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 overcast, and some rain had fallen. The closest ground-based witness, who was several hundred feet below the helicopter, stated that it was "windy," but his local topography was very different from the LZ topography. None of the passengers reported any wind.
It could not be determined what weather information the pilot obtained for the flight. Lockheed Martin Flight Services reported that no weather or other flight briefing services were provided for the helicopter in the 24 hours preceding the flight.
WRECKAGE AND IMPACT INFORMATION
The main wreckage, which consisted of the fuselage and tail boom, was located in a canyon below a pinnacle on Waterman Peak. Some rotor blade fragments, as well as fuselage and landing gear components, were distributed in the canyon, both above and below the main wreckage. The accident site elevation was approximately 3,595 feet.
The fuselage was on its left side, oriented approximately transversely across the canyon. The front canopy and canopy frame, as well as the aft 5 feet of the tail boom, were fracture-separated from the fuselage. Main rotor and tail rotor blade fragments were primarily found on top of the pinnacle. The rocky nature of the terrain limited the ground scarring. The rock outcrop at the top of the canyon contained main rotor blade fragments and scars. One 3-foot diameter shrub near the south east end of the LZ was uprooted, but its condition could not be directly associated with the accident sequence, and it may have been a result of rescue and recovery efforts.
The wreckage was examined in situ on the mountain on February 1, the day after the accident. The wreckage was recovered from the mountain on the afternoon of February 1, and examined in Phoenix on February 3 and 4. All components were accounted for. The five main rotor blades were highly fragmented, and their fragmentation and scoring damage was consistent with rotor strikes under power. The two tail rotor blades each were missing about 1/3 of their span, and the remaining root sections ...
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# WPR11GA115