N351SH

HISTORY OF FLIGHTOn March 27, 2021, about 1836 Alaska daylight time, an Airbus Helicopters AS350-B3, N351SH, was substantially damaged when it was involved in an accident near Palmer, Alaska. The pilot and four passengers were fatally injured, and one passenger was seriously injured. The helicopter was operated under Title 14 Code of Federal Regulations (CFR) Part 135 as an on-demand air charter flight.

Representatives from the operator, Soloy Helicopters, reported that the helicopter was under contract to Tordrillo Mountain Lodge (TML) to transport passengers from a private residence on Wasilla Lake, Wasilla, Alaska, to the Chugach Mountains to conduct heli-ski operations. (The Organizational and Management section of this report provides additional information about Soloy Helicopters and TML.) According to Heli Ski US (HSUS), which is a trade association that promotes helicopter skiing safety and provides support, heli-ski operations involve a “helicopter [that] is utilized to provide up-hill transportation for participants” of “guided winter recreation activities including, but not limited to skiing.”

GPS data showed that the helicopter arrived at the Wasilla Lake residence about 1450. About 53 minutes later, the helicopter departed the residence and flew toward the Chugach Mountains. The surviving passenger recalled “nice” but “kind of creepy weather” in the mountains, which delayed the departure for the ski trip. The helicopter arrived at the intended operating area about 19 minutes later and subsequently flew multiple runs between about 1612 and 1807.

GPS data showed that the helicopter departed for the last run of the day at 1827:05 on a northwest heading and climbed to about 5,900 ft mean sea level (msl). The helicopter's final movements began about 1833 over a ridgeline at an altitude of 6,266 ft msl (about 14 ft above ground level) and at a groundspeed of 1 knot. The helicopter maintained its low altitude and groundspeed as it maneuvered over the ridgeline. The data track ceased at 1836:42 near the location of the accident site, which is shown in figure 1.

Figure 1. Location of departure point, previous operating areas, and the accident site.

The surviving passenger stated that the passengers had completed five or six runs and that the accident occurred while the helicopter was relocating for the last run of the day. The surviving passenger also stated that the pilot first attempted to land the helicopter normally on the ridgeline but that the helicopter subsequently “went up to try to get into the right position.” The surviving passenger further stated that the snow was “real light” and that, while the pilot was attempting to land a second time, the helicopter was “engulfed in a fog, which made it appear like a little white room.” The passenger recalled that another passenger yelled “don’t do it” three times just before the helicopter “began going backward real fast and impacted the rocky mountainside several times.” PERSONNEL INFORMATIONA review of the pilot’s training records indicated that he completed recurrent training on January 21, 2021, including a pilot competency check and a line check, as required by 14 CFR 135.293 and 135.299, respectively. In addition, the pilot completed CFIT-A ground training in January 2021 and IIMC flight training in January 2020. Records showed that the IIMC flight training lasted 1 hour and covered “T/R [tail rotor] failures, autorotations, emergency ops.” The records did not indicate the specific IIMC training that the pilot received, and no other record was found showing IIMC flight training for the pilot. The IIMC flight training also included pinnacle landings and slopes and heli-ski and snow operations. AIRCRAFT INFORMATIONThe accident helicopter was equipped with a Garmin Aera 660 GPS, which was certified for visual flight rules (VFR) flight but had the capability to display IFR procedures and maps. The helicopter was also equipped with a Kannad 406-MHz AF Compact emergency locator transmitter (ELT) that was installed on the upper right side of the right baggage compartment. METEOROLOGICAL INFORMATIONAt 1600, the Anchorage, Alaska, upper air sounding wind profile indicated light surface wind from the north above the surface with little directional variation with height and increasing wind speed. At an altitude of about 6,000 ft, the wind was from 350° at 21 knots with a temperature of -17°C. The sounding was characterized as conditionally unstable below 6,000 ft and stable above that level.

The Universal Rawinsonde Observation analysis program sounding supported light turbulence below 8,000 ft and mountain wave activity. The northerly wind south of the ridgeline (the accident location) would have resulted in a general downslope wind flow near the accident site.

A pilot operating on Knik Glacier (near the accident site) a few hours before the accident reported light surface wind with stronger wind at altitude. This pilot indicated that it “was windy as heck at altitude but dead calm on the valley floor.” A snowmobile tour operator at Knik Glacier reported that, during the morning and afternoon tours on the day of the accident, he noticed large plumes of snow blowing off the nearby mountain peaks, and he estimated the wind to be between 30 to 40 miles per hour from the west. AIRPORT INFORMATIONThe accident helicopter was equipped with a Garmin Aera 660 GPS, which was certified for visual flight rules (VFR) flight but had the capability to display IFR procedures and maps. The helicopter was also equipped with a Kannad 406-MHz AF Compact emergency locator transmitter (ELT) that was installed on the upper right side of the right baggage compartment. WRECKAGE AND IMPACT INFORMATIONAerial assessment of the accident site on the day after the accident revealed that the helicopter impacted terrain about 15 to 20 ft below the top of the ridgeline. The main wreckage came to rest on its right side about 500 ft downslope from the initial impact area, as shown in figure 2. The debris field extended about 900 ft downslope from the top of the ridgeline.

Figure 2. Accident site (Source: Alaska State Troopers).

Postaccident examination of the airframe and engine revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation of the helicopter.

The ELT’s installed location (the upper right side of the right baggage compartment) was found packed with snow. The ELT remained secured to its airframe mount via a velcro strap. The ELT’s antenna coaxial cable and remote cockpit control wiring remained connected. The ELT switch was found in the ARM position. The external antenna had been fractured from its mount and was not located. Postaccident testing of the ELT found that it was working properly and that the ELT had transmitted during and after the accident sequence for 178 hours (12,884 bursts at 50-second intervals). ADDITIONAL INFORMATIONHeli-Ski Guides

Two passengers aboard the accident flight were heli-ski guides who TML contracted for the accident flight. Guides provide a critical safety role during a flight, and their responsibilities can include loading and unloading passengers, understanding surface snow conditions, and coordinating with pilots about landing and pickup zones. The HSUS operating guidelines specify duties for guides during the approach and landing, which include assisting the pilot with hazard and pickup zone identification, confirming clearances to terrain features on short final, and ensuring passenger safety after landing. TML offered annual training to heli-ski guides working at its operation each season, which the accident guides attended in January 2021.

TML was listed on the HSUS website as a member at the time of the accident. HSUS designated the accident guides as lead guides. According to HSUS, a lead guide is “an individual designated by an Outfitter to supervise the activities of one or more Groups and who meets the recommended qualifications for that position as established in the Guide Qualification Guidelines.” One of the accident guides was designated as the senior lead guide for the flight.

Flight-Locating Information

Soloy Helicopters had delegated flight-locating responsibilities to TML. The NTSB requested that the FAA provide a definition or clarification for the term “flight locating” given that the Federal Aviation Regulations did not define that term. The FAA acknowledged that “flight locating” is not defined but stated that 14 CFR 135.79, Flight Locating Requirements, stated that procedures were required to be established for locating each flight for which an FAA flight plan is not filed. The regulation specified the following procedures:

1. Provide the certificate holder with at least the information required to be included in a VFR flight plan.

2. Provide for timely notification of an FAA facility or search and rescue facility, if an aircraft is overdue or missing.

3. Provide the certificate holder with the location, date, and estimated time for reestablishing communications, if the flight will operate in an area where communications cannot be maintained.

The regulation also required that flight-locating information be retained at the certificate holder's principal place of business, or at another place designated by the certificate holder in its flight-locating procedures, until the completion of each flight.

Flight-following was not defined for Part 135 operations and was not required for aircraft operating under Part 135. The term “flight follower” generally refers to personnel who perform various flight support duties. MEDICAL AND PATHOLOGICAL INFORMATIONPilot

The State of Alaska Medical Examiner’s Office in Anchorage performed an autopsy of the pilot. His cause of death was multiple blunt force injuries. Toxicology testing performed by the FAA’s Forensic Sciences Laboratory detected no tested for substances.

Ski Guides

According to the autopsy inspection repor...