Accident at Talkeetna, Alaska, 30 Mar 2013 (N911AA)

Accident narrative

On March 30, 2013, at 2320 Alaska daylight time, a Eurocopter AS350 B3 helicopter, registration N911AA, crashed while maneuvering during a search and rescue flight near Talkeetna, Alaska. The helicopter was operated by the Alaska Department of Public Safety (DPS) as a public aircraft operations flight under Part 91. The airline transport pilot, an Alaska state trooper serving as a flight observer, and a stranded snowmobiler were killed, and the helicopter was destroyed by impact forces and a postcrash fire. Instrument meteorological conditions prevailed in the area at the time of the accident.

**The flight**

The mission was initiated after a snowmobiler called 911 at 1935 to report that his snowmobile was stuck in a ditch under a major power transmission line between Larson Lake and Talkeetna. The snowmobiler reported bruised ribs and a concern about developing hypothermia. After attempts to coordinate a ground rescue failed due to the distance and deteriorating weather, the Alaska State Troopers search and rescue coordinator contacted the pilot at 2019. The pilot checked the weather and accepted the mission.

The 55-year-old pilot held commercial and airline transport pilot certificates. He had accumulated about 10,693 total flight hours, including about 8,452 hours in helicopters. He had flown 3,415 hours for the Alaska DPS, of which 1,738 hours were on search and rescue missions. The pilot was not current for instrument flight; his logbooks showed 38.3 hours of instrument flight in helicopters, of which 0.5 hour was actual instrument time, with his most recent instrument helicopter flight logged in 1986. He was authorized by the department to use night vision goggles (NVGs), though the investigation found no record that he had received formal NVG training while employed by the Alaska DPS.

The helicopter was not certified for instrument flight rules (IFR) operations. It was equipped with a Garmin 430 GPS, a Garmin 296 GPS, an Avalex mapping display, and an Appareo Vision 1000 cockpit image, audio, and data recorder.

**Sequence of events**

The pilot departed Ted Stevens Anchorage International Airport at 2117. At 2142, he landed at a site called "Sunshine" near Talkeetna to pick up the trooper, who would serve as a flight observer. The helicopter departed Sunshine and flew north, landing on a frozen, snow-covered pond near the snowmobiler at 2156. The pilot and trooper walked to the snowmobiler, reaching him at 2220, and subsequently transported him to the helicopter.

The helicopter departed the frozen pond at 2313, destined for Sunshine, about 16 miles south. Images from the onboard recorder showed the pilot used his NVGs and a helmet-mounted lip light throughout the flight. The pilot had configured the Garmin 296 to display a course line to Sunshine, but he made no adjustments to the Garmin 430 or the Avalex system. The helicopter's turn-and-bank indicator remained disabled for the flight; witnesses reported the pilot routinely kept it disabled by pulling its circuit breaker.

After takeoff, the helicopter climbed to about 700 feet mean sea level (msl), or about 250 feet above ground level (agl), and accelerated to 60 knots. The pilot flew southwest and then southeast, circumnavigating a 1,000-foot hill while remaining below the cloud ceiling, at times slowing to 20 knots and flying as low as 100 feet agl. At 2316, the flight observer radioed the dispatcher that they were en route to Sunshine and requested an ambulance. This was the final radio transmission from the flight.

Between 2317:14 and 2317:49, the helicopter flew at altitudes between 1,000 and 1,100 feet msl over 900-foot terrain, slowing from 44 knots to 16 knots. At 2317:59, the helicopter began to climb and turn left rapidly with little forward airspeed. During this climbing turn, the pilot adjusted the course deviation indicator on the horizontal situation indicator.

At 2318:40, with the helicopter at high pitch and roll angles, the pilot pulled a knob to cage the attitude indicator, setting it to display a level flight attitude. The helicopter then entered a series of erratic turns, climbs, and descents. The recorded GPS data ended at 2320:17.

The MatCom dispatch center did not perform flight tracking, and no one was aware the helicopter was overdue until emergency medical services personnel waiting at Sunshine inquired about its arrival at 0039. The wreckage was located by a National Guard helicopter at 0930 the following morning.

**What the investigation found**

The helicopter was found inverted in snow-covered, wooded terrain. Examination of the wreckage revealed no evidence of pre-impact mechanical malfunction with the flight controls or the main transmission gears. The engine's reduction gearbox input pinion slippage mark indicated the engine was producing significant power when the main rotor struck the ground.

Images from the onboard recorder confirmed that the helicopter was responding to the pilot's control inputs and that no warning or caution lights illuminated during the flight. The Board concluded that the helicopter and its engine were operating normally.

Weather observations at Talkeetna Airport, about four miles west of the accident site, reported light rain and mist changing to snow at 2312. The Board concluded that soon after departure from the remote landing site, the helicopter likely encountered instrument meteorological conditions (IMC), including low clouds, heavy snow, and near-zero visibility. Although icing conditions were likely present, the recorder showed no evidence that the helicopter's performance was degraded.

The Board found that the pilot experienced a total loss of external visual references while operating close to terrain, leading him to attempt a transition to instrument flight. The pilot's action to cage the attitude indicator outside of level flight caused the instrument to provide erroneous and misleading information. The Board concluded that this action indicated the pilot distrusted the information he was seeing. The attitude indicator model installed in the helicopter was limited to indicating ± 25 degrees of pitch. The Board noted that if the helicopter exceeded this pitch, the indicator would stop at the limit, which the pilot may have interpreted as a malfunction. The Board found that FAA publications lack accurate information about these pitch indication limits.

Without external visual references, with an erroneously caged attitude indicator, and with the turn-and-bank indicator disabled, the pilot lacked accurate attitude information. The Board concluded that the helicopter's erratic maneuvers were consistent with the pilot's spatial disorientation, a loss of control in flight, and an inability to recover due to his lack of instrument experience.

The investigation identified several organizational and management issues within the Alaska DPS. At the time the pilot accepted the mission, forecasts indicated that conditions in the search area would be IFR, likely below the pilot's personal and department weather minimums. However, the Alaska DPS lacked organizational policies and procedures to ensure operational risk was appropriately managed, such as formal pilot weather minimums, preflight risk assessment forms, or secondary assessment by another qualified person. The Board concluded that the pilot's exceptionally high motivation for search and rescue missions, combined with past successes in high-risk weather situations, likely increased his risk tolerance and influenced his decision to continue flying in deteriorating weather.

Additionally, the trooper serving as the flight observer had not been trained to use the helicopter's navigational equipment or NVGs. The Board concluded that a tactical flight officer capable of assisting with aeronautical decision-making and operating the systems could have helped mitigate risk, but inadequate management support for a tactical flight officer program led to the unavailability of a trained observer on the day of the accident.

The Board also found that the Alaska DPS had a punitive safety culture. Following a 2006 accident and subsequent incidents involving the pilot, department investigations focused heavily on pilot culpability rather than systemic safety issues. The Board concluded that this seemingly punitive culture appeared to impede the free flow of safety-related information, causing the pilot to adopt a defensive posture and make safety-related decisions in a vacuum, which impaired the organization's ability to address underlying safety deficiencies.

**Probable cause**

The National Transportation Safety Board determined that the probable cause of this accident was the pilot's decision to continue flight under visual flight rules into deteriorating weather conditions, which resulted in the pilot's spatial disorientation and loss of control. Also causal was the Alaska Department of Public Safety's punitive culture and inadequate safety management, which prevented the organization from identifying and correcting latent deficiencies in risk management and pilot training. Contributing to the accident was the pilot's exceptionally high motivation to complete search and rescue missions, which increased his risk tolerance and adversely affected his decision-making.