History of Flight
On May 5, 2016, about 1405 Alaska daylight time, an Airbus (formerly Eurocopter) AS 350 B2 helicopter, registration N194EH, collided with snow-covered mountainous terrain while on approach to a remote landing site on the Norris Glacier, approximately 15 miles northeast of Juneau, Alaska. The commercial pilot was seriously injured, and the helicopter sustained substantial damage. The helicopter was registered to and operated by Era Helicopters, LLC, under Title 14 Code of Federal Regulations Part 91 as a visual flight rules (VFR) internal-cargo company flight. Degraded visual meteorological conditions were reported on the Norris Glacier at the time of the accident. Company flight following procedures were in effect. The flight originated about 1341 from a heliport at the operator's headquarters on Douglas Island in Juneau.
Alaska Heli-Mush, Inc., contracted with Era Helicopters to provide helicopter support for moving personnel, dogs, and cargo. The purpose of the flight was to transport camp equipment from Era Helicopters' headquarters to a remote dog camp on the Norris Glacier in the Tongass National Forest. Era Helicopters and Alaska Heli-Mush conducted heli-mushing operations for the Alaska tourism industry under a helicopter glacier landing permit issued by the US Forest Service.
At 1307, a weather report from the dog camp indicated a 300-ft ceiling and 5 miles visibility. At 1341, the pilot departed on the first flight of the day from the heliport for the approximate 25-minute flight with an internal cargo load of 850 pounds and no passengers. During an interview with a National Transportation Safety Board (NTSB) investigator on May 11, 2016, the pilot reported that during the approach over a large, featureless, snow-covered ice field, ceilings were "low," and he observed "a lot of flat light." He stated that during the approach he was in radio contact with dog camp personnel. He was scanning his radar altimeter, which indicated 200 ft above ground level, and he had visually acquired the landing zone and dog camp when the helicopter struck the snow-covered ice field and rolled over to the right. The pilot reported no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation and characterized the accident as controlled flight into terrain.
After impact, the pilot released himself from the fiberglass seat's 4-point restraint system and attempted to perform an emergency shutdown. Dog camp personnel responded via snowmobile and rendered first aid to the pilot, who was lying on the snow. The accident site was about 3/4 mile from the dog camp landing zone near Guardian Mountain. Dog camp personnel notified Era's operational control center at 1405 and Era's Juneau base at 1408. At 1409, the operator's base initiated the emergency response plan.
Personnel Information
The pilot, age 39, held a commercial pilot certificate with rotorcraft-helicopter and helicopter instrument ratings. His most recent first-class medical certificate was issued on January 7, 2016, with the limitation that he must wear corrective lenses. According to the operator, the pilot's total aeronautical experience was about 3,428 hours, of which about 2,084 hours were in the accident helicopter make and model. In the 30 days before the accident, the pilot flew a total of 15 hours. The operator's training records showed no deficiencies and indicated that the pilot completed all required training, including a competency check ride on March 30, 2016. The operator reported that flight operations in flat light conditions and inadvertent instrument meteorological conditions (IIMC) recovery are trained and checked annually.
Aircraft Information
The 1992-model-year helicopter was equipped with a Safran (formerly Turbomeca) Arriel 1D1 turboshaft engine. At the time of the accident, the helicopter had accumulated 11,735.9 flight hours, and the engine 8,741.90 hours. The most recent inspection of the airframe and engine was completed on May 3, 2016. An examination of maintenance records revealed no evidence of uncorrected mechanical discrepancies. The helicopter was configured to be flown from the right front seat, which was a non-energy attenuating, fiberglass seat. The left front seat was a two-place, non-energy attenuating, fiberglass seat installed via a supplemental type certificate. The helicopter was equipped with a radar altimeter. The attitude indicator displayed the minimum required ±25° pitch indication. An emergency floatation system was installed on the skid system; snow/tundra boards were not installed.
The operator configured the cabin to facilitate internal cargo transport. The rear seat assembly was folded up against the cabin wall, and a lidded plastic box containing a metal heater was placed on the cabin floor behind the pilot's seat. A single cargo strap was secured to the rear seatbelt attachment points in front of the aft cabin wall and routed over the box from left to right. The configuration provided lateral restraint but no forward restraint. The make, model, and maximum load rating of the strap could not be determined. According to cargo paperwork, the box and its contents weighed 50 pounds.
Meteorological Information
The closest official weather observation station was Juneau International Airport, about 16 miles southwest. At 1353, reported conditions were: wind 120° at 15 knots, visibility 8 statute miles, few clouds at 1,300 ft, broken clouds at 3,900 ft, temperature 45°F, dew point 41°F, altimeter 30.21 inches of mercury.
Wreckage and Impact Information
The wreckage was recovered and transported to a secure hangar at Juneau International Airport. On May 10, 2016, a wreckage examination and layout were conducted under the direction of the NTSB investigator-in-charge, with representatives from the FAA, Airbus, Safran, and Era. Damage was noted to the fuselage, main rotor system, tailboom, and tail rotor system. No preimpact mechanical malfunctions or failures were noted. Postaccident photos showed the cargo strap remained intact; the metal heater was ejected from the plastic box and lying behind the pilot's seat. The seatback showed a fracture at about shoulder height, and removal of the seat cushion revealed a complete transverse fracture of the seatback, lower on the left side than the right side.
Additional Information
Carriage of Internal Cargo in Airbus AS 350 Series Helicopters
The NTSB submitted inquiries to the FAA regarding carriage of internal cargo. The FAA responded that it does not require OEMs to publish cargo loading information, and that any approved cargo installation would be explained in the rotorcraft flight manual (RFM) limitations or supplement section. The FAA stated that operators do not have certification approval to install cargo unless mentioned in the RFM or RFM supplement. A review of the AS 350 B2 RFM found a placard mounted on the control pedestal stating the "distributed loads maximum" for the rear cabin floor is 682 pounds. No other cargo carriage information was found in the RFM. The Airbus AS 350 Systems and Description Manual states that after removing the front left seat and folding back the rear benches, the cabin floor can be used to transport cargo, with eleven mooring points embedded in the floor, and the limit permissible force on a mooring ring is 620 dekanewtons (1,393.7 pound-force). Airbus stated that it is the operator's responsibility to define adapted cargo securement respecting the floor mooring ring limitations.
Helicopter Internal Cargo Securement
The US Army's Training Circular 3-04.4 discusses cargo securement, noting that forward movement is the strongest force during sudden deceleration. Restraint criteria are expressed in Gs. No specific FAA regulatory guidance, advisory material, or best practices regarding internal cargo securement or cargo strap maintenance were identified.
Flat Light Conditions and Glacier Flight Operations
The FAA's publication "Flying in Flat Light and White Out Conditions" describes flat light as an optical illusion that causes loss of depth-of-field and contrast, often occurring over snow-covered areas. It advises pilots to be conscious of altitude when flying over glaciers.
Training Device and Simulator Usage
The operator reported that a level 6 flight training device is used for initial AS 350 training but not for recurrent training.
Survival Aspects
The pilot was seated in the right front seat, wearing a 4-point restraint system. He did not wear a flight helmet (not required). Postaccident medical treatment records indicated injuries including fractures of multiple left ribs, left scapula, multiple left-sided transverse and spinous process fractures, injuries to the left lung, left kidney, and spleen, and an intimal tear in the mid-descending aorta.
Organizational and Management Information
Era's Operations Manual required a risk assessment at the beginning of each flight day. The pilot conducted a formal flight risk assessment using form ERA A-003, with a total value of 15; no section limits were exceeded (the flight would be prohibited if total exceeded 32 or any section limit was exceeded). Company VFR weather minimums for overland day flights were: minimum operating height 500 ft, cloud base 600 ft, 3 statute miles visibility. Flights could not depart or continue if reported weather was below these minimums without documented approval. The manual included sections on flat light procedures, stating that the pilot in command shall use the radar altimeter for altitude reference over large flat areas, monitor airspeed and vertical speed more often during approaches, ensure a good reference point, and maintain a good scan. For internal cargo, the manual stated that cargo may only be carried in the passenger compartment during cargo-only operations and must be secured by an approved means. The operator reported that internal cargo loading is covered in company training.