# NTSB WPR21LA077: Bell 47D, N74823, Marana, AZ, January 1, 2021 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 4 · Limited · Final report - Date: January 1, 2021, 13:15 local (20:15 UTC) - Place: Marana, AZ · Airport - Coordinates: 32.409556, -111.21838 - Nearby events: https://openairdocs.org/map.md?lat=32.4096&lon=-111.2184&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Defining event: [Taxi: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - NTSB case key (mKey): 102484 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA077 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102484/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102484 - Page: https://openairdocs.org/ntsb/WPR21LA077 ## Probable cause The pilot's failure to maintain helicopter control, which resulted in a hard landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Bell 47D1, 3 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=1180802), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: yaw control](https://openairdocs.org/ntsb-findings/01062024): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Bell 47D1, 1 case](https://openairdocs.org/ntsb-findings/01062024/cases.md?model=1180802), [All aircraft, 149 cases](https://openairdocs.org/ntsb-findings/01062024/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Taxi: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Bell 47D1, 3 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=1180802), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) ## Analysis The helicopter pilot reported that, while hover taxing on the taxiway, a Cessna airplane taxied from the ramp onto the same taxiway and turned toward and approached the helicopter. The helicopter pilot assumed that the Cessna would turn onto another taxiway toward the runway, however the Cessna continued toward the helicopter. The helicopter pilot stated that he went into a vertical lift, but "due to low rotor RPM the helicopter went into a loss of control spin". The helicopter landed hard to the left of the taxiway, substantially damaging the fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation. ## Aircraft - Registration: [N74823](https://openairdocs.org/aircraft/N74823), registered now, S/N 270, built 1953 (OpenAirDocs) - Reported make and model: BELL 47D (1) - Registry model: [Bell 47D1](https://openairdocs.org/model/bell-47d1) (registry code 1180802) (OpenAirDocs) - Registry engine: [Franklin 6V4 series](https://openairdocs.org/engine/franklin-6v4-series) (registry code 27033, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 270 - Year built: 1953 - Airframe hours: 7526 - Engines: FRANKLIN 6V4 SERIES 210 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, November 24, 2020 - Departed: KRYN, Tucson, AZ - Destination: Same as departure - Airport: KAVQ, Marana Rgnl - Equipment: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: minor; private; airplane ratings: single-engine land; medical: class 3, unknown; last flight review May 30, 2020; seat: left; restraint: lap only; flight hours: 2,400 total, 32 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 65 °F - Altimeter: 30.05 inHg - Observed at: KAVQ ## 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 20210101001599A](https://openairdocs.org/incident/20210101001599A), Jan 1, 2021: Bell 47D1, Marana, AZ, Substantial damage. While hover taxiing back to ramp on taxiway, a CE-182 entered the same taxiway approaching the helicopter. PIC stated that no radio contact could be made with… ## Other investigations on N74823 (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 GAA15CA221](https://openairdocs.org/ntsb/GAA15CA221), Aug 11, 2015: Bell 47D1 (N74823), Clanton, AL, substantial damage. Probable cause: The student pilot's abrupt cyclic and collective inputs during the approach to land which resulted in abnormal runway contact and a subsequent tail boom strike by the main rotor blades. ## Docket (2 files) The files NTSB released with the investigation on August 20, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102484. 6.2 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 12 pages, 5.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12599855&FileExtension=pdf&FileName=WPR21LA077%20Pilot%20Report_Redacted-Rel.pdf - Photo of damage (source unknown) (item 2, PDF, 1 page, 473 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12600348&FileExtension=pdf&FileName=WPR21LA077%20Damage%20Photo%20Source%20Unknown-Rel.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.