# NTSB LAX06CA003: Aerospatiale AS350B, N31MH, Grand Canyon, AZ, October 4, 2005 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: October 3, 2005, 17:10 local (Oct 4, 2005, 00:10 UTC) - Place: Grand Canyon, AZ - Coordinates: 33.62931, -112.090744 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.6293&lon=-112.0907&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 7 uninjured - Status: Completed, report February 28, 2006 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 62602 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX06CA003 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/62602/pdf - Page: https://openairdocs.org/ntsb/LAX06CA003 ## Probable cause the pilot's failure to maintain control of the helicopter during landing in gusty wind conditions, which resulted in a hard landing and ground resonance. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Hard landing, landing - flare/touchdown - weather condition - gusts - aircraft control - not maintained, pilot in command (cause) - ground resonance - encountered, pilot in command (cause) ## Analysis The helicopter encountered a ground resonance event following a hard landing in gusty wind conditions. The pilot reported that the winds were from the south at 18 knots with gusts to 36 knots. He hover-taxied to the helipad for landing following a sightseeing tour and had established the helicopter in a 3-foot hover in preparation for landing. A gust of wind disrupted the helicopter and brought it to a 6-foot hover. The pilot regained control and stabilized it back in a 3-foot hover. Another gust of wind "slammed" the helicopter onto the helipad and a ground resonance event began. The pilot lifted the helicopter back into the air upon noticing the increasing vibrations. After the vibrations dissipated, the pilot set it back onto the helipad. ## Factual narrative On October 3, 2005, at 1710 Pacific daylight time, an Aerospatiale AS350B, N31MH, encountered a ground resonance event following a hard landing at the Grand Canyon Airport (GCN), Grand Canyon, Arizona. The commercial rotorcraft pilot and six passengers were not injured; the helicopter sustained substantial damage. The helicopter was registered to, and operated by, Maverick Helicopters, Las Vegas, Nevada, as a sightseeing flight under the provisions of 14 CFR Part 135. The tour flight originated from GCN at 1647, and was terminating at the time of the accident. Visual meteorological conditions prevailed, and a company visual flight rules flight plan had been filed. According to the pilot's written statement, he established the helicopter in a 3-foot hover and taxied to the helipad. As the helicopter neared the helipad, a "gust of wind lifted the aircraft into a 5- to 6-foot hover." The pilot regained control and reestablished the helicopter in a 3-foot hover and began lowering the collective to land. At 1.5 feet above the ground, another gust of wind "slammed" the helicopter onto the ground, impacting the terrain with the right front skid. A "violent vibration" began, and the pilot pulled the helicopter up in the air after realizing he was in a ground resonance situation. The vibrations dissipated, and the pilot set the helicopter down and shut off the engine. The helicopter sustained substantial damage to its tail boom. Post accident examination of the landing skid system revealed that the spring-steel extensions were within limits and the dampers were in serviceable condition. The pilot did not report any anomalies with the helicopter prior to the event. The pilot reported that the winds were from the south at 18 knots with gusts to 36 knots. ## Aircraft - Registration: N31MH (not matched to a registry record) - Reported make and model: Aerospatiale AS350B - Category: Helicopter - Serial number: 2141 - Airframe hours: 8933 - Engines: Turbomeca Arial 1D1 700 horsepower turbo shaft - Damage: Substantial damage - Flight: Part 135 - Registered owner: Maverick Helicopters Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, September 1, 2005, 92.3 hours before - Departed: GCN, Grand Canyon, AZ - Flight plan: Company VFR - Airport: GCN, Grand Canyon National Park ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 22; injuries: none; flight instructor, commercial; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review July 1, 2005; seat: left; flight hours: 1,790 total, 240 in this make and model, 240 in the last 90 days, 50 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 18 knots, gusting 36 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 73 °F - Altimeter: 30.02 inHg ## 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 20051003022499A](https://openairdocs.org/incident/20051003022499A), Oct 3, 2005: Snias AS350B, Grand Canyon, AZ, Substantial damage. (-23) The pilot was setting the helicopter down on a pad with a gusting tailwind. A gust of wind apparently forced the aircraft to suddenly impact hard on the… 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.