# NTSB WPR09CA470: Robinson Helicopter R44 II, N29LE, Mt Charleston, NV, September 28, 2009 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Data collection · Final report - Date: September 27, 2009, 18:30 local (Sep 28, 2009, 01:30 UTC) - Place: Mt Charleston, NV - Coordinates: 36.27111, -115.695831 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=36.2711&lon=-115.6958&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: Minor injuries - Injuries: 1 minor, 2 uninjured - Status: Completed, report December 29, 2009 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 74813 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09CA470 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74813/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74813 - Page: https://openairdocs.org/ntsb/WPR09CA470 ## Probable cause The pilot's failure to maintain aircraft control and terrain clearance while maneuvering at a low altitude above high terrain. Contributing to the accident was a downdraft and high density altitude. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Robinson Helicopter R44 II, 4 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=7640122), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md) - [Temp/humidity/pressure: high density altitude](https://openairdocs.org/ntsb-findings/03031020): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Robinson Helicopter R44 II, 11 cases](https://openairdocs.org/ntsb-findings/03031020/cases.md?model=7640122), [All aircraft, 278 cases](https://openairdocs.org/ntsb-findings/03031020/cases.md) - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Robinson Helicopter R44 II, 39 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=7640122), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Robinson Helicopter R44 II, 99 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7640122), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Robinson Helicopter R44 II, 45 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=7640122), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Post-impact: Fire/smoke (post-impact)](https://openairdocs.org/ntsb-events/170); cases with it: [Robinson Helicopter R44 II, 5 cases](https://openairdocs.org/ntsb-events/170/sequence.md?model=7640122), [All aircraft, 354 cases](https://openairdocs.org/ntsb-events/170/sequence.md) ## Analysis The pilot stated that he was orbiting at 50 knots about 100 feet above the 11,800-foot mean sea level (msl) mountain peak. As he flew the helicopter out of the leeward side of the peak, he encountered a downdraft. He maneuvered the helicopter toward a wide open valley that descended about 5,000 feet below. The downdraft pushed the helicopter into the face of the mountain, despite the pilot's application of full collective and descending flight into the valley. The helicopter impacted the mountain slope, caught fire, and tumbled. The pilot and his two passengers egressed the burning helicopter with minor injuries. The pilot hiked to the peak, and called for rescue using a cell phone. The calculated density altitude for the conditions was 13,918 feet. The published maximum operating density altitude for the helicopter was 14,000 feet. The pilot stated that the helicopter had no mechanical failures or malfunctions during the flight. ## Factual narrative The pilot stated that he was orbiting at 50 knots about 100 feet above the 11,800-foot msl (mean sea level) mountain peak. As he flew the helicopter out of the leeward side of the peak, he encountered a downdraft. He maneuvered the helicopter towards a wide open valley that descended about 5,000 feet below. The downdraft pushed the helicopter into the face of the mountain despite the pilot's application of full collective, and descending flight into the valley. The helicopter impacted the mountain slope, caught fire, and tumbled. The pilot and his two passengers egressed the burning helicopter with minor injuries. The pilot hiked to the peak, and called for rescue using a cell phone. The calculated density altitude for the conditions at 11,800 feet msl, altimeter 29.78 inHg, and temperature of 47 degrees F, is 13,918 feet. The published maximum operating density altitude for the R-44 II is 14,000 feet. The pilot stated that the helicopter had no mechanical failures or malfunctions during the flight. ## Aircraft - Registration: [N29LE](https://openairdocs.org/deregistered/N29LE-2012-06-21), registration cancelled 2012-06-21, S/N 10269, built 2004 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER COMPANY R44 II - Registry model: [Robinson Helicopter R44 II](https://openairdocs.org/model/robinson-helicopter-r44-ii) (registry code 7640122) (OpenAirDocs) - Registry engine: [Lycoming IO-540 series](https://openairdocs.org/engine/lycoming-io-540-series) (registry code 41530, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 10269 - Airframe hours: 2492 - Engines: LYCOMING IO-540 SER 300 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Personal, Part 91 - Operator: Mojave Aviation - Registered owner: Bank Of Utah Trustee - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 19, 2009, 94 hours before - Departed: KVGT, Las Vegas, NV - Destination: KVGT, Las Vegas, NV - Airport: KVGT, North Las Vegas ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane, helicopter; medical: class 1; last flight review November 7, 2008; seat: right; flight hours: 2,578 total, 359 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F, dew point 28 °F - Altimeter: 29.78 inHg - Observed at: KVGT, 35 nm away ## 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 20090927019419A](https://openairdocs.org/incident/20090927019419A), Sep 27, 2009: Robins R44II, Las Vegas, NV, Destroyed. On September 27, 2009, at approximately 1830 local time, N29LE, a Robinson helicopter (R-44-II), crashed and burned, approximately 10,000 feet MSL 20 miles wnw… ## Docket (2 files) The files NTSB released with the investigation on October 21, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74813. 1.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 520 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40320066&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Photo 1 - On scene (item 2, .PDF, 961 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40320067&FileExtension=.PDF&FileName=Photo%201%20-%20On%20scene-Master.PDF 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.