What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
AS-350 was conducting heliski operations and unloading skiers during toe-in maneuver on ~20 degree slope at approx. 5500 foot level. Slope was direct lighted by sun and winds were out of north at ~20 knots. Face of slope was ene.
This was third landing at this site and two of the four skiers were outside the aircraft when a flat piece of loose shale approximately 2 inch in diameter flew into rotor system from right side. Pilot felt slight bump but had no indications or vibration. Pilot stopped unloading and repositioned upslope abot 30 feet to avoid additional rock ingestion. When unloading last two skiers, pilot informed them that he was goint to reposition to the base of the Mountain on Glacier to shutdown and look at blades before he picked them up.
After departure from second slope, pilot began normal descent to fly to valley floor. After ~30 secs, aircraft developed very slight 1:1 vibration but was not abnormal. After another 15 seconds of flight, the vibration drastically increased while aircraft was at ~1000 foot AGL and flying away from the hillside. Pilot immediately turned back toward the hillside and began search for landing area. About the time he got aimed at the hill, the aircraft experienced a violent buck pitch up indicitive of hydraulic failure. At this point the aircraft and controls were shaking so badly that aircraft control was minimal and it was hard to focus outside. After controls began to lock up, pilot pointed aircraft at lightest colored terrain (most snow, least trees) and the aircraft impacted hard and rolled to its right side and came to rest with severed tailboom approx 1/2 mile from initial toe-in site.
No injuries experienced, ELT not activated, spot message sent with lat long, and recovery completed.
As of 02 April 2019, aircraft had not been recovered from accident site. After initial advice from flm to wait for a/c recovery to allow wreckage examination, decision made to close this action with airman counseling iaw compliance program, ptrs 201901839. If any subsequent data recovered during wreckage examination, pertinent information will be added to this report.
As the FAA filed it
AS-350 WAS CONDUCTING HELISKI OPERATIONS AND UNLOADING SKIERS DURING TOE-IN MANEUVER ON ~20 DEGREE SLOPE AT APPROX. 5500 FOOT LEVEL. SLOPE WAS DIRECT LIGHTED BY SUN AND WINDS WERE OUT OF NORTH AT ~20 KNOTS. FACE OF SLOPE WAS ENE.
THIS WAS THIRD LANDING AT THIS SITE AND TWO OF THE FOUR SKIERS WERE OUTSIDE THE AIRCRAFT WHEN A FLAT PIECE OF LOOSE SHALE APPROXIMATELY 2 INCH IN DIAMETER FLEW INTO ROTOR SYSTEM FROM RIGHT SIDE. PILOT FELT SLIGHT BUMP BUT HAD NO INDICATIONS OR VIBRATION. PILOT STOPPED UNLOADING AND REPOSITIONED UPSLOPE ABOT 30 FEET TO AVOID ADDITIONAL ROCK INGESTION. WHEN UNLOADING LAST TWO SKIERS, PILOT INFORMED THEM THAT HE WAS GOINT TO REPOSITION TO THE BASE OF THE MOUNTAIN ON GLACIER TO SHUTDOWN AND LOOK AT BLADES BEFORE HE PICKED THEM UP.
AFTER DEPARTURE FROM SECOND SLOPE, PILOT BEGAN NORMAL DESCENT TO FLY TO VALLEY FLOOR. AFTER ~30 SECS, AIRCRAFT DEVELOPED VERY SLIGHT 1:1 VIBRATION BUT WAS NOT ABNORMAL. AFTER ANOTHER 15 SECONDS OF FLIGHT, THE VIBRATION DRASTICALLY INCREASED WHILE AIRCRAFT WAS AT ~1000 FOOT AGL AND FLYING AWAY FROM THE HILLSIDE. PILOT IMMEDIATELY TURNED BACK TOWARD THE HILLSIDE AND BEGAN SEARCH FOR LANDING AREA. ABOUT THE TIME HE GOT AIMED AT THE HILL, THE AIRCRAFT EXPERIENCED A VIOLENT BUCK PITCH UP INDICITIVE OF HYDRAULIC FAILURE. AT THIS POINT THE AIRCRAFT AND CONTROLS WERE SHAKING SO BADLY THAT AIRCRAFT CONTROL WAS MINIMAL AND IT WAS HARD TO FOCUS OUTSIDE. AFTER CONTROLS BEGAN TO LOCK UP, PILOT POINTED AIRCRAFT AT LIGHTEST COLORED TERRAIN (MOST SNOW, LEAST TREES) AND THE AIRCRAFT IMPACTED HARD AND ROLLED TO ITS RIGHT SIDE AND CAME TO REST WITH SEVERED TAILBOOM APPROX 1/2 MILE FROM INITIAL TOE-IN SITE.
NO INJURIES EXPERIENCED, ELT NOT ACTIVATED, SPOT MESSAGE SENT WITH LAT LONG, AND RECOVERY COMPLETED.
AS OF 02 APRIL 2019, AIRCRAFT HAD NOT BEEN RECOVERED FROM ACCIDENT SITE. AFTER INITIAL ADVICE FROM FLM TO WAIT FOR A/C RECOVERY TO ALLOW WRECKAGE EXAMINATION, DECISION MADE TO CLOSE THIS ACTION WITH AIRMAN COUNSELING IAW COMPLIANCE PROGRAM, PTRS 201901839. IF ANY SUBSEQUENT DATA RECOVERED DURING WRECKAGE EXAMINATION, PERTINENT INFORMATION WILL BE ADDED TO THIS REPORT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.