# NTSB ERA21LA339: Enstrom 280, N9285, Port Orange, FL, August 21, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: August 21, 2021, 13:30 local (17:30 UTC) - Place: Port Orange, FL - Coordinates: 29.079762, -81.04711 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=29.0798&lon=-81.0471&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: Enstrom Helicopter, FAA/FSDO - NTSB case key (mKey): 103759 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA339 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103759/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103759 - Page: https://openairdocs.org/ntsb/ERA21LA339 ## Probable cause The failure of the tail rotor drive shaft at the coupling due to torsionally applied shear stress. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Tail rotor drive system: tail rotor drive shaft](https://openairdocs.org/ntsb-findings/01046510): Aircraft › Aircraft propeller/rotor · Failure (probable cause); cases with it: [Enstrom Helicopter 280C, 1 case](https://openairdocs.org/ntsb-findings/01046510/cases.md?model=3300505), [All aircraft, 25 cases](https://openairdocs.org/ntsb-findings/01046510/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern final: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Enstrom Helicopter 280C, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=3300505), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Enstrom Helicopter 280C, 3 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=3300505), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The pilot was conducting a local flight when just prior to touchdown, the helicopter began to spin to the right and made an uncommanded climb and spin to the right. The pilot applied full left rudder pedal, but the helicopter continued to spin to the right. He lowered the collective and landed hard on the skids, which resulted in substantial damage to the fuselage. Postaccident examination of the helicopter revealed the tail rotor driveshaft was separated and free to spin inside the coupling. Metallurgical examination of the driveshaft revealed the bolt holes in the driveshaft were distorted, consistent with torsional shear-stress in the clockwise direction. ## Factual narrative On August 21, 2021, about 1330 eastern daylight time, an Enstrom 280C, N9285, was substantially damaged when it was involved in an accident in Daytona Beach, Florida. The pilot was not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91personal flight. According to the pilot, he conducted a local flight around Spruce Creek Airport (7FL6), Daytona Beach, Florida, and was approaching to land. Just prior to touchdown, the helicopter made an uncommanded climb and started to spin to the right. The pilot applied full left pedal, but the helicopter continued to spin to the right. He lowered the collective and the helicopter landed hard on the skids. The left skid was damaged during, fuselage frame, and the tail rotor blades were damaged during the landing. Postaccident examination of the helicopter revealed that the tail rotor driveshaft was free to spin inside the coupling and not connected by a through bolt. The coupling and a section of the drive shaft were forwarded to the National Transportation Safety Board’s Material Laboratory for further examination. The examination revealed that the bolt holes in the drive shaft tube were mechanically distorted consistent with the presence of an axially applied torsional shear-stress in the drive shaft tube in the clockwise direction. Macroscopically, the fracture surface in the drive shaft tube was consistent with overstress due to torsionally applied shear stress (for more information, see Materials Laboratory Factual Report in the public docket for this investigation). ## Aircraft - Registration: [N9285](https://openairdocs.org/aircraft/N9285), registered now, S/N 1003, built 1978 (OpenAirDocs) - Reported make and model: ENSTROM 280 (C) - Registry model: [Enstrom Helicopter 280C](https://openairdocs.org/model/enstrom-helicopter-280c) (registry code 3300505) (OpenAirDocs) - Registry engine: [Lycoming HI0-360 series](https://openairdocs.org/engine/lycoming-hi0-360-series) (registry code 41553, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 1003 - Year built: 1978 - Airframe hours: 2326 - Engines: Lycoming HIO-360-EIAD 205 hp reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Mark Sherman - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 1, 2021 - Airport: 7FL6, Spruce Creek, runway 24, 4,000 × 176 ft - Equipment: Electronic flight bag or handheld device, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 73; injuries: none; private; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review July 28, 2021; seat: left; restraint: 4-point; flight hours: 4,829 total, 62 in this make and model, 3,455 as pilot in command, 49 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 250° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 18,000 ft broken - Temperature: 93 °F, dew point 75 °F - Altimeter: 29.96 inHg - Observed at: KDAB, 6 nm away - METAR: KDAB 211753Z 25005KT 10SM SCT044TCU SCT055 BKN180 BKN250 34/24 A2996 RMK AO2 SLP144 TCU SW-NW DSNT SE-S T03440239 10350 20261 57007 $ ## 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 20210821022239A](https://openairdocs.org/incident/20210821022239A), Aug 21, 2021: Enstrom Helicopter Corp 280C, Port Orange, FL, Substantial damage. On August 21, 2021, about 1330 eastern daylight time, an Enstrom 280C, N9285, was substantially damaged from a accident in daytona beach, Florida. The Pilot… ## Docket (7 files) The files NTSB released with the investigation on July 26, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103759. 21.9 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13589941&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Memorandum for record a�� telephone interview, pilot (item 2, PDF, 1 page, 122 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13589715&FileExtension=pdf&FileName=Record%20of%20Interview-Mark%20Sherman-Rel.pdf - Memorandum for record a�� telephone interview, mechanic (item 3, PDF, 1 page, 124 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13590618&FileExtension=pdf&FileName=Record%20of%20Interview-mechanic-Rel.pdf - Materials laboratory report (item 4, PDF, 22 pages, 17.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13590628&FileExtension=pdf&FileName=Materials%20Laboratory%20Factual%20Report%2021-103-Rel.pdf - Investigative photos (item 5, PDF, 5 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13591508&FileExtension=pdf&FileName=Investigative%20Photo-Rel.pdf - Evidence control form (item 6, PDF, 1 page, 113 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13639001&FileExtension=pdf&FileName=Evidence-Control-Form-Rel.pdf - Statement of party representatives to NTSB investigation (item 7, PDF, 1 page, 190 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13591150&FileExtension=pdf&FileName=Party%20form_Redacted-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.