# NTSB ERA15CA059: Hiller OH 23B, N6057, Leesburg, VA, November 24, 2014 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: November 24, 2014, 11:30 local (16:30 UTC) - Place: Leesburg, VA - Coordinates: 39.078056, -77.557502 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.0781&lon=-77.5575&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report March 10, 2015 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 90428 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA15CA059 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/90428/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=90428 - Page: https://openairdocs.org/ntsb/ERA15CA059 ## Probable cause A loss of tail rotor effectiveness while hovering in gusting crosswind conditions resulting in the student pilot's loss of control of the helicopter. Contributing was the delayed remedial action of the flight instructor. ## 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: [Hiller OH-23B, 2 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=4360109), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Action: delayed action](https://openairdocs.org/ntsb-findings/02041025): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Hiller OH-23B, 2 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md?model=4360109), [All aircraft, 894 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Hiller OH-23B, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=4360109), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Landing-flare/touchdown: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Hiller OH-23B, 2 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=4360109), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis Following an uneventful preflight inspection of the helicopter, the flight instructor and the student pilot boarded the helicopter for a local instructional flight. About 10 seconds after the student pilot lifted the helicopter into a stable hover with a left crosswind, the helicopter began a slow yaw to the right that the student was unable to arrest through the application of the left anti-torque pedal. As the rate of the yaw increased, the flight instructor took control of the helicopter and attempted to stop the yaw with the application of additional left anti-torque pedal, to no avail. The flight instructor then reduced engine power, arresting the yaw, and performed an autorotation to the ground after an estimated 1 3/4 total revolutions. As the helicopter touched down, it rocked backwards, and the tail rotor struck the helicopter's ground handling dolly, resulting in substantial damage to the tail rotor. The flight instructor did not report any pre-impact mechanical malfunctions or failures of the helicopter. Archived weather data showed that wind velocity about the time of the accident was 15 knots, with gusts to 24 knots. According to Federal Aviation Administration Advisory Circular 90-95, pilots are advised to be aware that, "…if a considerable amount of left pedal is being maintained, a sufficient amount of left pedal may not be available to counteract an unanticipated right yaw." Additionally, pilots should, "Stay vigilant to power and wind conditions." ## Factual narrative Following an uneventful preflight inspection of the helicopter, the flight instructor and the student pilot boarded the helicopter for a local instructional flight. About 10 seconds after the student pilot lifted the helicopter into a stable hover with a left crosswind, the helicopter began a slow yaw to the right that the student was unable to arrest through the application of the left anti-torque pedal. As the rate of the yaw increased, the flight instructor took control of the helicopter and attempted to stop the yaw with the application of additional left anti-torque pedal, to no avail. The flight instructor then reduced engine power, arresting the yaw, and performed an autorotation to the ground after an estimated 1 3/4 total revolutions. As the helicopter touched down, it rocked backwards, and the tail rotor struck the helicopter's ground handling dolly, resulting in substantial damage to the tail rotor. The flight instructor did not report any pre-impact mechanical malfunctions or failures of the helicopter. Archived weather data showed that wind velocity about the time of the accident was 15 knots, with gusts to 24 knots. According to Federal Aviation Administration Advisory Circular 90-95, pilots are advised to be aware that, "…if a considerable amount of left pedal is being maintained, a sufficient amount of left pedal may not be available to counteract an unanticipated right yaw." Additionally, pilots should, "Stay vigilant to power and wind conditions." ## Aircraft - Registration: [N6057](https://openairdocs.org/aircraft/N6057), registered now, S/N 54-2930, built 1954 (OpenAirDocs) - Reported make and model: HILLER OH 23B (NO SERIES) - Registry model: [Hiller OH-23B](https://openairdocs.org/model/hiller-oh-23b) (registry code 4360109) (OpenAirDocs) - Category: Helicopter - Serial number: 54-2930 - Year built: 1954 - Airframe hours: 3119 - Engines: Franklin 6V-350-B 235 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Vertically Challenged LLC - Registered owner: Vertically Challenged LLC - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 14, 2014 - Departed: JYO, Leesburg, VA - Destination: JYO, Leesburg, VA - Flight plan: VFR - Airport: JYO, Leesburg Executive ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 44; injuries: none; commercial, flight instructor; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review November 21, 2013; seat: left; restraint: lap only; flight hours: 3,090 total, 11 in this make and model, 2,936 as pilot in command, 45 in the last 90 days, 13 in the last 30 days, 0 in the last 24 hours - Student pilot; age 46; injuries: none; flight instructor, student, commercial, airline transport; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review September 25, 2014; seat: center; restraint: lap only; flight hours: 3,879 total, 13 in this make and model, 3,772 as pilot in command, 116 in the last 90 days, 33 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 15 knots, gusting 24 - Visibility: 10 statute miles - Lowest ceiling: 2,600 ft overcast - Temperature: 66 °F, dew point 59 °F - Altimeter: 29.64 inHg - Observed at: KJYO ## 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 20141124023609A](https://openairdocs.org/incident/20141124023609A), Nov 24, 2014: Hiller OH-23B, Leesburg, VA, Substantial damage. N6057, a Hiller UH-12C was purchased in June 2014 by vertically challenged, LLC. [privacy data omitted], The student at the time of accident is the co-owner.… ## Docket (3 files) The files NTSB released with the investigation on February 25, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=90428. 2.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 749 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40422830&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Photo 1 – View of Helicopter from Front Right (Photo Courtesy of Flight Instructor) (item 2, .PDF, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40422831&FileExtension=.PDF&FileName=Photo%201%20%E2%80%93%20View%20of%20Helicopter%20from%20Front%20Right%20(Photo%20Courtesy%20of%20Flight%20Instructor)%0D%0A-Master.PDF - Photo 2 – View of Damage to Tail Rotor (Photo Courtesy of Flight Instructor) (item 3, .PDF, 575 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40422832&FileExtension=.PDF&FileName=Photo%202%20%E2%80%93%20View%20of%20Damage%20to%20Tail%20Rotor%20(Photo%20Courtesy%20of%20Flight%20Instructor)%0D%0A-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.