# NTSB CEN12CA031: Hughes 269A, N10375, Fort Worth, TX, October 14, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: October 14, 2011, 09:20 local (14:20 UTC) - Place: Fort Worth, TX - Coordinates: 32.819721, -97.36222 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.8197&lon=-97.3622&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Defining event: [Standing-engine(s) operating: Ground resonance](https://openairdocs.org/ntsb-events/232) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report December 27, 2011 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 82113 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN12CA031 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/82113/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=82113 - Page: https://openairdocs.org/ntsb/CEN12CA031 ## Probable cause The inadvertent entry into ground resonance after a hovering autorotation. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: prop/rotor parameters](https://openairdocs.org/ntsb-findings/01062052): Aircraft › Aircraft oper/perf/capability · Not attained/maintained; cases with it: [Hughes 269A, 7 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md?model=4470402), [All aircraft, 182 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Instructor/check pilot (probable cause); cases with it: [Hughes 269A, 9 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=4470402), [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. - [Standing-engine(s) operating: Ground resonance](https://openairdocs.org/ntsb-events/232) (defining event); cases with it: [Hughes 269A, 3 cases](https://openairdocs.org/ntsb-events/232/sequence.md?model=4470402), [All aircraft, 21 cases](https://openairdocs.org/ntsb-events/232/sequence.md) ## Analysis The certified flight instructor (CFI) and pilot receiving instruction were practicing hovering autorotations on a taxiway. With the skids on the ground for about 20 seconds after completing a hovering autorotation and with the engine at 2,000 rpm, the helicopter began to vibrate and violently shake, consistent with ground resonance. The vibrations and shaking continued to increase and lasted about 15 to 30 seconds. After the shaking stopped, the CFI shut down the helicopter. A postaccident examination of the helicopter revealed that the tail rotor and gearbox separated, and the fuselage was bent and deformed. No preimpact mechanical malfunctions or failures with the helicopter were noted that would have precluded normal operation. ## Factual narrative After practicing some flight and landing maneuvers, the certified flight instructor and pilot receiving instruction decided to practice some hovering autorotations on a taxiway. With the skids on the ground for approximately 20 seconds after completing a hovering autorotation and the engine at 2,000 RPM, the helicopter began to vibrate and violently shake. The vibrations and shaking continued to increase and lasted approximately 15 to 30 seconds. After the shaking stopped, the certified flight instructor shutdown the helicopter. Postaccident examination of the helicopter revealed the tail rotor and gearbox separated, and the fuselage was bent and deformed. No preimpact mechanical malfunctions or failures with the helicopter were noted that would have precluded normal operation. ## Aircraft - Registration: [N10375](https://openairdocs.org/aircraft/N10375), registered now, S/N 67-18376 (OpenAirDocs) - Reported make and model: HUGHES 269A - Registry model: [Hughes 269A](https://openairdocs.org/model/hughes-269a) (registry code 4470402) (OpenAirDocs) - Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 67-18376 - Airframe hours: 6176 - Engines: LYCOMING HIO-360-B1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: On File - Registered owner: On File - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 25, 2011 - Departed: FTW, Fort Worth, TX - Destination: FTW, Fort Worth, TX - Airport: FTW, Fort Worth Mecham Intl. Airpor ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 40; injuries: none; flight instructor, private, commercial; airplane ratings: single-engine land; medical: class 2, without waivers/limitations; last flight review July 18, 2010; seat: left; flight hours: 803 total, 98 in this make and model, 732 as pilot in command, 49 in the last 90 days, 15 in the last 30 days - Pilot; age 40; injuries: none; airline transport, flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review February 8, 2011; seat: right; flight hours: 6,377 total, 65 in this make and model, 4,954 as pilot in command, 47 in the last 90 days, 17 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 54 °F, dew point 50 °F - Altimeter: 29.97 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 20111014028709A](https://openairdocs.org/incident/20111014028709A), Oct 14, 2011: Hughes 269A, Ft. Worth, TX, Destroyed. Calm clear day. Instructor and student flying Hughes 269 on a checkout flight. Both instructor and student stated that they were doing auto rotations from a… ## Docket (2 files) The files NTSB released with the investigation on November 17, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=82113. 5.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 366 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40358021&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Pilot Receiving Instruction Statement (item 2, .PDF, 4.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40357812&FileExtension=.PDF&FileName=Pilot%20Receiving%20Instruction%20Statement-Redacted.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.