# NTSB ANC06LA137: Aerospatiale SA319B, N119PH, Port Alsworth, AK, September 24, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 23, 2006, 16:30 local (Sep 24, 2006, 00:30 UTC) - Place: Port Alsworth, AK - Coordinates: 60.24139, -156.404449 - Nearby events: https://openairdocs.org/map.md?lat=60.2414&lon=-156.4044&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 30, 2007 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA-AL-ANC FSDO 03 - NTSB case key (mKey): 64592 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC06LA137 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/64592/pdf - Page: https://openairdocs.org/ntsb/ANC06LA137 ## Probable cause The pilot's failure to adequately secure the external load rigging of an airplane that was suspended from the helicopter, which resulted in a load shift during cruise flight, producing an abrupt nose-down attitude, and the severing of the tailrotor drive shaft by the main rotor blades. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Cargo shift, cruise - security of cargo - inadequate, pilot in command (cause) - external load sling/harness - shifted (cause) - Rotor failure/malfunction, cruise - rotor drive system,tail rotor drive shaft - sheared (cause) - rotor system,main rotor hub lead-lag stop/damper - fractured - Forced landing, emergency descent/landing - autorotation - performed, pilot in command - Hard landing, emergency descent/landing - misc rotorcraft,main rotor/tail boom contact - separation - terrain condition - tundra ## Analysis During a Title 14, CFR Part 133 flight, the commercial certificated pilot was transporting a previously crashed airplane on a 100 foot external load line. The external load line was attached to a spreader bar that was attached to the wing structure of the airplane. While flying about 60 knots, and about 2,000 feet above ground level (agl), the pilot felt the load shift, becoming light, or unloaded, and he began to slow the helicopter's airspeed. The helicopter then suddenly pitched nose-down about 45 degrees. The tail boom of the helicopter was struck by one or more main rotor blades, severing the tail rotor drive shaft. The pilot released the external load from the belly of the helicopter and entered an autorotation. About 1,000 feet agl, the pilot shut the engine off, and performed a touch down autorotation. During the landing on soft tundra, one of the main landing gear wheels dug into the terrain, and the helicopter's tail boom was struck by the main rotor blades, severing about two feet of the aft end of the tail boom. The pilot did not determine the cause of the external load shift. ## Factual narrative On September 23, 2006, about 1630 Alaska daylight time, a wheel-equipped Aerospatiale SA319B helicopter, N119PH, sustained substantial damage during an emergency landing following an in-flight loss of control while in cruise flight, about 62 miles west-southwest of Port Alsworth, Alaska. The helicopter was being operated as a visual flight rules (VFR) cross-country external load operation from a remote area under Title 14, CFR Part 133, when the accident occurred. The helicopter was operated by Last Frontier Air Ventures Ltd., Sutton, Alaska. The commercial certificated pilot and the one crewmember aboard were not injured. Visual meteorological conditions prevailed, and VFR company flight following procedures were in effect. The flight originated from the area of the Mulchatna River, and was en route to Port Alsworth. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on September 24, the pilot/owner, who also is the director of operations, reported that he was transporting a previously crashed Piper PA-18 airplane on a 100 foot external load line. The external load line was attached to a spreader bar that was attached to the wing structure of the airplane. The wings had wing covers designed to spoil lift. The pilot said he was flying about 60 knots, and about 2,000 feet above ground level (agl), when he felt the load shift. He indicated that it felt as if the suspended airplane became light, or unloaded, and he immediately began to slow the helicopter's airspeed. The helicopter then suddenly pitched nose-down about 45 degrees. The tail boom of the helicopter was struck by one or more main rotor blades, severing the tail rotor drive shaft, and one or more of the main rotor hub spacing cables broke at their frangible bolt attach points. The pilot said when he released the external load from the belly of the helicopter and entered an autorotation, the helicopter descended with a severe lateral vibration in the main rotor system. The pilot said that about 1,000 feet agl, he shut the engine off, and performed a touch-down autorotation. During the landing on soft tundra, one of the main landing gear wheels dug into the terrain, and the helicopter's tail boom was struck by the main rotor blades, severing about two feet of the aft end of the tail boom. The pilot reported that after the external load was released, the suspended PA-18 airplane sustained extensive damage when it struck the ground. The pilot did not determine the cause of the external load shift. ## Aircraft - Registration: [N119PH](https://openairdocs.org/aircraft/N119PH), registered now, S/N 2119 (OpenAirDocs) - Reported make and model: Aerospatiale SA319B - Registry model: [Aerospatiale SA319B ALOUETTE III](https://openairdocs.org/model/aerospatiale-sa319b-alouette-iii) (registry code 8680607) (OpenAirDocs) - Category: Helicopter - Serial number: 2119 - Airframe hours: 4914 - Engines: Turbomeca Astazou 14 870 horsepower turbo shaft - Damage: Substantial damage - Flight: External load, Part 133 - Registered owner: Last Frontier Air Ventures Ltd. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, April 1, 2006, 34 hours before - Departed: PALJ, Port Alsworth, AK - Destination: Port Alsworth, AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; injuries: none; commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review September 1, 2006; seat: right; flight hours: 12,200 total, 1,600 in this make and model, 12,100 as pilot in command, 200 in the last 90 days, 80 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 135° at 12 knots, gusting 18 - Visibility: 40 statute miles - Lowest ceiling: 7,000 ft overcast - Temperature: 50 °F ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20060923021739A](https://openairdocs.org/incident/20060923021739A), Sep 23, 2006: Aerosp SA319B, Port Alsworth, AK, Substantial damage. (-23) The pilot reported that he was transporting a previously crashed Piper PA-18 airplane on a 100 foot external load line. The external load line was… ## Other investigations on N119PH (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB ANC03LA042](https://openairdocs.org/ntsb/ANC03LA042), Apr 7, 2003: Aerospatiale SA-319B (N119PH), Valdez, AK, substantial damage. Probable cause: The pilot's encounter with a ground resonance condition during the landing touchdown, which resulted in the shearing of a main rotor spacing cable bolt, and buckling of the tail boom. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.