N855HW

HISTORY OF FLIGHTOn March 25, 2010, about 0600 central daylight time (CDT), a Eurocopter AS350 B3, N855HW, impacted terrain near Brownsville, Tennessee. The certificated commercial pilot and two flight nurses were fatally injured; the helicopter was substantially damaged. The helicopter was registered to and operated by Memphis Medical Center Air Ambulance Service, doing business as Hospital Wing, under the provisions of 14 Code of Federal Regulations Part 91 as a positioning flight. Night visual meteorological conditions prevailed for the flight, which operated on a visual flight rules flight plan. The flight originated from Jackson-Madison County General Hospital Heliport (TN05), Jackson, Tennessee, about 0551 and was en route to Haywood County EMS Heliport (99TN), Brownsville, Tennessee.

According to satellite tracking and witness interviews, the helicopter initially departed its home base (99TN) about 0426 and arrived in Parsons, Tennessee, about 0450 to pick up a patient. The helicopter departed Parsons about 0517 and arrived at TN05 to drop off the patient about 0534. The helicopter subsequently departed TN05 about 0551, and the last satellite contact occurred near the accident site about 0600. Satellite-recorded data indicated that the helicopter flew about 1,000 feet above mean sea level (msl) during the last flight segment until the last contact, when the helicopter's altitude indicated 752 feet msl (about 350 feet above ground level [agl]) and 105 miles per hour (mph).

According to an oncoming shift pilot who started his duty about 0530, it was dark, cloudy, and lightly raining when he arrived at 99TN. When he entered the hangar, he noticed that the helicopter was gone. He was concerned about the weather and called MedCom, a flight following center, to locate the helicopter, which was then on the pad at TN05. After hanging up with MedCom, the accident pilot called the oncoming pilot via cellular telephone and asked about the weather. The oncoming pilot indicated in a postaccident interview that the accident pilot stated that he "wanted to get the helicopter out." The oncoming pilot asked, "Can you park it?" The oncoming pilot stated that the accident pilot then responded that another helicopter already occupied the lower elevation pad, which the oncoming pilot took to mean that the accident pilot did not want to leave the helicopter on the hospital's elevated pad.

The two pilots further discussed the weather, and the oncoming pilot noted, from a computer-based radar depiction, that a front was coming from the Memphis area about 65 miles southwest at an estimated speed of about 25 mph. At the time, the radar was depicting "red" over Memphis and "yellow" extending about 10 miles out.

The oncoming pilot reported that the accident pilot told him that he believed he had about 18 minutes to beat the storm and return to home base. He told the oncoming pilot to call the two flight nurses, who were not yet on board the helicopter, to advise them that he was going to take off and that they would be picked up later by car. The oncoming pilot stated that he tried to call one of the flight nurses, but she had left her phone back at the base. When he called the other nurse and told her the plan, she stated that they had already made it back to the helicopter and were 7 minutes out from the base.

The oncoming pilot reported in a postaccident interview that he raised the door of the hangar and then went back to look at the weather radar again, noting that the thunderstorm line had "just barely touched the southwest corner of [the] county," which was about 18 miles from base. He went outside, could not see the helicopter, and called the flight nurse again. When she answered, she asked about the weather. The oncoming pilot saw the blinking light on a radio tower to the east, about 6 miles away, "so visibility was good." He told the nurse that she "had the weather beat." The nurse then stated that they were 30 seconds out.

At the time of the conversation, the oncoming pilot observed that it was raining lightly but that the wind had picked up, perhaps to about 20 knots. Then, just after hanging up, he heard an "immediate" loud clap of thunder and saw lightning that made him jump. He looked out, saw no helicopter, and tried to call the nurse without success. He then called MedCom and ran up the hill to contact the ambulance service located there. As he did so, it was raining harder than before, but it was not a soaking rain.

The helicopter was located in a field about 1,500 feet southwest of the last airborne target recorded by satellite about 0600. The accident location was about 2.5 miles east of the helicopter's home base. PERSONNEL INFORMATIONThe pilot, age 58, held a commercial pilot certificate, with airplane single-engine and multiengine land, rotorcraft helicopter, instrument airplane, and instrument helicopter ratings. According to company records, the pilot was initially hired by Hospital Wing on May 10, 2005. At that time, he indicated that he had about 2,200 hours of helicopter flight time, and since then, he had accrued about 415 additional hours.

The pilot's latest Part 135 airman competency/proficiency check was completed on August 26, 2009, and his latest instrument competency check was completed on February 14, 2010. The pilot's initial and only night vision goggles (NVG) training was completed on July 27, 2009. His latest Federal Aviation Administration (FAA) second class medical certificate was issued on March 15, 2009, with the restriction that he possess glasses for near and intermediate vision. He reported a total of 4,008 flight hours on that date.

The pilot was off duty on March 18, 19, and 22. On March 20, he recorded an 8-hour duty day with no flying time. On March 21, he recorded 2.9 flight hours, all during the day. On March 23, he recorded 0.9 flight hours, including 0.2 hours during the day, 0.2 hours at night (without NVG), and 0.5 hours at night (with NVG). On March 24 (the evening before the accident), he recorded 0.4 hours at night. The pilot's wife reported that she called him at work about 2130 on March 24. She stated that he seemed normal during the conversation and did not complain of any fatigue or tiredness. She was not at home when he went to work that day, but she did report that he "always slept well." She indicated that when he worked night shifts, he would sleep for most of the day. AIRCRAFT INFORMATIONThe accident helicopter was a Eurocopter AS350 B3 model that was manufactured in 2008. It was equipped with a three blade main rotor system and a two blade tail rotor system and was powered by a 747-shaft horsepower Turbomeca Arriel 2B1 engine.

According to aircraft records, American Eurocopter delivered the helicopter to Hospital Wing in May 2009. At the time of delivery, the helicopter was equipped with high-skid landing gear, NVG and NVG-compatible lighting, a vehicle engine multifunction display (VEMD), an autopilot, and an enhanced ground proximity warning system (EGPWS). Hospital Wing subsequently sent the helicopter to Metro Aviation, Shreveport, Louisiana, for aftermarket installations, including a medical interior. The helicopter was configured with the pilot seat in the right front position, the medical litter extending from the left front to the left aft cabin bulkhead, and medical crew seat backs against the aft cabin bulkhead.

A review of maintenance records revealed that the most recent 200 hour and annual inspections were accomplished on March 1, 2010, at 199.6 hours total time since new (TTSN). At the time of the accident, the helicopter had accrued approximately 248 hours TTSN, and no outstanding discrepancies were listed in the maintenance records. METEOROLOGICAL INFORMATIONWeather recorded about 0553 at McKeller-Sipes Regional Airport (MKL), Jackson, Tennessee, about 17 miles east of the accident site, included winds from 160 degrees true at 5 knots, visibility greater than 10 miles, a few clouds at 2,000 feet, a broken cloud layer at 2,700 feet, an overcast cloud layer at 3,700 feet, temperature 16 degrees C, dew point 12 degrees C, an altimeter setting of 29.77 inches of mercury, and distant lightning to the southwest.

About 0609 (about 9 minutes after the accident), MKL reported winds from 220 degrees at 15 knots with gusts to 19 knots, visibility 9 miles, thunderstorms in the vicinity, broken ceiling at 1,800 feet agl, overcast cloud base at 2,700 feet agl, temperature 15 degrees C, dew point 12 degrees C, and an altimeter setting of 29.84 inches of mercury. Remarks noted distant lightning in the south and west octants and a thunderstorm that began about 0603.

Radar images indicated that, about the time of the accident, a mesoscale convective system (MCS), or line of thunderstorms, was moving through the area, southwest to northeast, at a groundspeed of about 61 knots. A portion of the 50+ dBZ radar reflectivity pattern of this MCS was characterized by a "bow echo," which included localized instrument meteorological conditions (IMC), heavy rain, lightning, and wind gusts up to 20 knots. The near-surface region immediately ahead of an advancing MCS, known as the gust front, is an area prone to extreme low-level wind shear that often occurs in clear air.

Infrared satellite imagery indicated extensive cloud cover over far-western Tennessee during the time of the accident, with cloud tops at 30,000 feet and greater.

A report of cloud-to-ground lightning strikes from the National Lightning Detection Network indicated that, within a 15-mile radius of the accident site between 0400 and 0605, one strike occurred at 0602:08. An additional report was obtained from the WeatherBug Total Lightning Network (WTLN). From 0545 to 0615, WTLN detected 6 cloud-to-ground strikes and 12 intercloud strikes; however, none occurred within 90 seconds of the accident time.

Three witnesses near the accident site stated that they saw lightning and heard thunder at th...