Accident Details
Probable Cause and Findings
An in-flight overtorque of the engine-to-transmission driveshaft resulting in disconnection of the main transmission from the engine. The overtorque likely occurred due to an in-flight main rotor blade contact with snow-covered terrain, precluding significant main rotor blade damage and ground scarring. Contributing to the severity of the surviving occupant's injuries was the helicopter operator's failure to properly monitor their satellite flight-following system and to immediately institute a search once the system reported that the helicopter was overdue.
Aircraft Information
Registered Owner (Historical)
Analysis
**This report was modified on July 7, 2015. Please see the public docket for this accident to view the original report.**
HISTORY OF FLIGHT
On April 15, 2008, about 0923 Alaska daylight time, a Eurocopter AS-350-B2 helicopter, N213EH, sustained substantial damage during an emergency descent and impact with terrain, about 34 miles east of Chickaloon, Alaska. The helicopter was being operated as a visual flight rules (VFR) cross-country passenger flight under Title 14, CFR Part 135, when the accident occurred. The helicopter was owned and operated by ERA Helicopters, LLC., Anchorage, Alaska. The commercial pilot and three passengers were killed, and one passenger, the 15-year-old stepson of one of the deceased passengers, sustained serious injuries. Visual meteorological conditions were reported in the area at the time of the accident, and company flight following procedures were in effect. The flight originated at the operator's base in Anchorage about 0742, en route to various communication sites near Chickaloon.
During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on April 17, the operator's general manager reported that the purpose of the flight was to shuttle State of Alaska telecommunications technicians and equipment between three remote communication sites near Chickaloon. He noted the helicopter departed the Anchorage base with only the pilot aboard. The manager said that the pilot was instructed to land at the State of Alaska's telecommunication heliport in Anchorage to pick up three technicians and their equipment, and then fly to the communication sites near Chickaloon.
During a telephone conversation with the NTSB IIC on April 17, a technician that was aboard the helicopter when it departed from the Anchorage telecommunications facility reported that after departure the crew planned to meet an additional technician at the first of three communication sites to drop off equipment. He said as they approached the first site they realized that the technician they planned to meet was not there, so they continued to the second site. The technician said the helicopter landed at the second site about 0900, and left him there. It was agreed that the helicopter would return by 1300 to pick him up. The technician reported that after the helicopter departed from the second site, and before continuing on to the third site to drop off the two remaining technicians and their equipment, the pilot was to fly to a rest area along the highway, and pick up one other technician that would be waiting with additional equipment to be transported to the third communication site. The technician said he was unaware that the other technician would have his stepson with him.
When the flight failed to return by 1300, the technician contacted the State of Alaska's telecommunications shop, but was told that the other technicians had a lot of work to do, and to give them more time. When the flight still had not returned by 1400, the technician again contacted the State of Alaska's telecommunications shop. As a result, the State notified the operator, who attempted unsuccessfully to contact the helicopter via satellite telephone and aircraft radio. The operator reported the helicopter overdue to the Federal Aviation Administration (FAA) at 1540, and they contacted the Air Force Rescue Coordination Center.
The Air Force Rescue Coordination Center (AFRCC) at Elmendorf Air Force Base, Anchorage, had received the first alert of a signal from a 121.5 MHZ emergency locator transmitter (ELT) signal at 1121 that day. They were unaware at the time that the accident helicopter had crashed, but were already in the process of organizing a search related to the unknown source of the ELT signal.
Personnel of the Alaska State Troopers, Civil Air Patrol, Alaska Mountain Search and Rescue, and the Alaska Air National Guard, were dispatched to search for the helicopter, but blizzard weather conditions limited search personnel to a ground search until weather conditions improved the next day.
The helicopter's wreckage was located on April 16, about 0750, in an area of hilly, tree-covered terrain, about three-quarters of a mile from the highway rest area where the technician and his stepson were picked up. Additional details of the search and rescue follow in the Search and Rescue section of this report.
During an interview with the NTSB IIC on May 27, the sole survivor of the accident, a 15-year-old juvenile, reported that he was asked to accompany his stepfather, who was a telecommunications technician with the State of Alaska, to the third communication site. The boy said that after the helicopter landed in the parking area of the highway rest stop, the pilot shutdown the helicopter before additional equipment was loaded. He said that before departing from the parking lot, he was placed in the front left seat, and the other three passengers were seated in the aft seats. The juvenile noted that he took with him a small day-pack, which contained a bag lunch and two bottles of water. He did not recall where he placed the day-pack.
Due to injuries sustained in the accident, the juvenile said he was unable to recall many details of the accident.
According to management personnel with ERA Helicopters, and management personnel with the State of Alaska's Telecommunications Division, neither knew that the juvenile was on board the accident helicopter.
On the morning of the accident, a motorist about one mile south, traveling northbound on the highway saw the helicopter lift off from the roadside, and fly in an east south-east direction. The motorist estimated the visibility to be about 2 miles in light snow. He said he saw the helicopter flying below the overcast, and it made a steep descending right turn toward the ground. He said initially he thought the helicopter was going to crash, but as he approached the area where the helicopter departed, he saw the ravine where the helicopter made the descent. The motorist was familiar with helicopter operations from his job working on the Alaska pipeline, and thought the helicopter was probably working in the ravine. He said it was not unusual to see helicopters working along the highway, but he thought the steep descent was unusual, and commented to a friend after arriving at his work site, about the helicopter and the scary ride the pilot must have given the passengers. He said he did not hear about the accident until several days later, and then contacted the IIC.
INJURY TO PERSONS
The pilot and four passengers were aboard the helicopter at the time of the accident. The helicopter wreckage was reached by rescuers about 24 hours after the accident. The pilot in the right front seat and the two passengers in the right rear and center rear seats were found dead in the helicopter. The third passenger in the left rear seat had exited the helicopter, and was found dead outside the helicopter. The fourth passenger, the juvenile, had been seated in the left front seat, and was found incoherent, wandering in a ravine at the base of the slope where the helicopter impacted. He was transported to a hospital in an Alaska State Trooper helicopter, and according to the transporting helicopter's observer/EMT, he had a head injury, and was suffering from hypothermia.
DAMAGE TO AIRCRAFT
The helicopter received substantial damage to the fuselage, tail boom, tail and main rotor systems, and the rotor drive train.
PERSONNEL INFORMATION
The pilot held a commercial helicopter certificate with a helicopter instrument rating. He also held a helicopter flight instructor certificate with an instrument helicopter rating. His most recent second-class medical certificate was issued on March 5, 2008, and contained no limitations.
According to the Pilot/Operator Aircraft Accident Report, (NTSB Form 6120.1) submitted by ERA Helicopters, the pilot's total aeronautical experience was about 3,747 flight hours, of which about 1,889 flight hours were in the accident helicopter make and model. In the preceding 90 and 30 days prior to the accident, the pilot flew a total of 47.3 and 9.6 flight hours.
The operator's pilot training records showed no deficiencies, and that the accident pilot had completed all required training, including a required CFR Part 135 proficiency check ride on June 11, 2007.
AIRCRAFT INFORMATION
The helicopter was a Eurocopter AS-350-B2, equipped with a Turbomeca Arriel 1D1 turboshaft engine.
The helicopter was maintained under the operator's Approved Aircraft Inspection Program (AAIP), which requires inspections to be performed approximately every 100 flight hours. The helicopter had 4,983.7 flight hours in service at the time of the accident 11 flight hours had elapsed since the most recent phase inspection. An examination of the helicopter's maintenance logs showed no mechanical discrepancies.
METEOROLOGICAL INFORMATION
The technician who was dropped off at the second communications site said the weather had been good along the route from their departure in Anchorage to the site where he left the helicopter, but by 1400 he said he could see bad weather rapidly approaching from the southwest. He said he knew that if they did not depart soon the approaching weather would preclude the use of the helicopter. The helicopter did not return, and the technician spent the night at the communication site due to the snowstorm that arrived shortly after 1400.
The closest weather reporting station was the automated weather station at Sheep Mountain Airport, 4.5 miles to the west of the accident site. The automated weather observation at 0850 ADT the morning of the accident recorded the wind from 250 degrees at 3 knots, visibility 2 statute miles, ceiling 400 feet overcast, altimeter 29.42 inches of mercury, temperature 27 degrees F, and dew point 23 degrees F.
The accident site was about three-quarters of a mile to the east of the Glen...
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# ANC08FA053