# NTSB GAA15CA221: Bell 47D1, N74823, Clanton, AL, August 11, 2015 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: August 11, 2015, 15:00 local (19:00 UTC) - Place: Clanton, AL - Coordinates: 32.851112, -86.608055 - Nearby events: https://openairdocs.org/map.md?lat=32.8511&lon=-86.6081&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report September 30, 2015 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 91762 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA15CA221 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/91762/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=91762 - Page: https://openairdocs.org/ntsb/GAA15CA221 ## 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. ## 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 · Student/instructed 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) - [Main rotor system: main rotor blade system](https://openairdocs.org/ntsb-findings/01046210): Aircraft › Aircraft propeller/rotor · Incorrect use/operation (probable cause); cases with it: [Bell 47D1, 2 cases](https://openairdocs.org/ntsb-findings/01046210/cases.md?model=1180802), [All aircraft, 60 cases](https://openairdocs.org/ntsb-findings/01046210/cases.md) - [Performance/control parameters: pitch control](https://openairdocs.org/ntsb-findings/01062022): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Bell 47D1, 1 case](https://openairdocs.org/ntsb-findings/01062022/cases.md?model=1180802), [All aircraft, 526 cases](https://openairdocs.org/ntsb-findings/01062022/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-flare/touchdown: Abrupt maneuver](https://openairdocs.org/ntsb-events/270); cases with it: [Bell 47D1, 1 case](https://openairdocs.org/ntsb-events/270/sequence.md?model=1180802), [All aircraft, 346 cases](https://openairdocs.org/ntsb-events/270/sequence.md) - [Landing-flare/touchdown: Loss of control in flight](https://openairdocs.org/ntsb-events/240); 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) - [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092) (defining event); cases with it: [Bell 47D1, 5 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=1180802), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The flight instructor reported that while conducting an approach to landing, terminating at a three foot hover, the student pilot "pulled back on the cyclic and dumped collective", which caused the main rotor blades to contact the tail boom after the helicopter impacted the ground "hard". The flight instructor reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. The helicopter sustained substantial damage to the tail boom and to the empennage. ## Factual narrative The flight instructor reported that while conducting an approach to landing, terminating at a three foot hover, the student pilot "pulled back on the cyclic and dumped collective", which caused the main rotor blades to contact the tail boom after the helicopter impacted the ground "hard". The flight instructor reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. The helicopter sustained substantial damage to the tail boom and to the empennage. ## Aircraft - Registration: [N74823](https://openairdocs.org/aircraft/N74823), registered now, S/N 270, built 1953 (OpenAirDocs) - Reported make and model: BELL 47D1 (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: 7861 - Engines: FRANKLIN 6V4-200-C32 200 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Gilliland, Kenneth L. - Registered owner: Gilliland, Kenneth L. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, July 1, 2015, 10 hours before - Departed: 02A, CLANTON, AL - Destination: 02A, CLANTON, AL - Airport: 02A, Chilton County, runway 26, 4,008 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Student pilot; age 68; injuries: none; airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review April 28, 2015; seat: left; restraint: lap only; flight hours: 7,320 total, 3.7 in this make and model, 5,611 as pilot in command, 29.5 in the last 90 days, 6 in the last 30 days, 0.8 in the last 24 hours - Flight instructor; age 63; injuries: none; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review March 18, 2015; seat: right; restraint: lap only; flight hours: 6,328 total, 250 in this make and model, 6,194 as pilot in command, 52 in the last 90 days, 21 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 320° at 5 knots - Visibility: 10 statute miles - Temperature: 90 °F, dew point 73 °F - Altimeter: 29.95 inHg - Observed at: KEET, 21 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 20150811016529A](https://openairdocs.org/incident/20150811016529A), Aug 11, 2015: Bell 47D1, Clanton, AL, Substantial damage. 08/11/2015 1500 Local time winds were observed as 340 at 10 KTS. Student pilot was manipulating the controls of N74823 a Bell 47D1 on final terminating with a… ## 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 WPR21LA077](https://openairdocs.org/ntsb/WPR21LA077), Jan 1, 2021: Bell 47D (N74823), Marana, AZ, substantial damage. Probable cause: The pilot's failure to maintain helicopter control, which resulted in a hard landing. ## Docket (2 files) The files NTSB released with the investigation on September 14, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=91762. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (Flight Instructor) (item 1, .PDF): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431785&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1%20(Flight%20Instructor)-Redacted.PDF - Photo 1 - Tail Boom and Empennage Damage (Photo Courtesy of FAA) (item 2, .PDF, 3.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431786&FileExtension=.PDF&FileName=Photo%201%20-%20Tail%20Boom%20and%20Empennage%20Damage%20(Photo%20Courtesy%20of%20FAA)-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.