# NTSB CEN18LA334: Schweizer 269C, N3625Z, Kindred, ND, August 16, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: August 16, 2018, 10:30 local (15:30 UTC) - Place: Kindred, ND - Coordinates: 46.667778, -97.008056 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.6678&lon=-97.0081&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: 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: Central Region - Parties: Federal Aviation Administration - Fargo FSDO - ADs cited in the narratives: [AD 93-17-13](https://openairdocs.org/ad/93-17-13), [AD 2017-14-06](https://openairdocs.org/ad/2017-14-06) (OpenAirDocs) - NTSB case key (mKey): 98084 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN18LA334 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/98084/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=98084 - Page: https://openairdocs.org/ntsb/CEN18LA334 ## Probable cause The pilot’s failure to adequately inspect the lower coupling driveshaft during his preflight inspection and his non-compliance with an applicable airworthiness directive, which resulted in the failure of the forward drive splines of the lower coupling driveshaft during cruise flight. Co-causal to the accident was the pilot’s failure to maintain control of the helicopter during the autorotation landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Main rotor drive: engine/transmission coupling](https://openairdocs.org/ntsb-findings/01046310): Aircraft › Aircraft propeller/rotor · Failure (probable cause); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-findings/01046310/cases.md?model=8059500), [All aircraft, 24 cases](https://openairdocs.org/ntsb-findings/01046310/cases.md) - [Main rotor drive: engine/transmission coupling](https://openairdocs.org/ntsb-findings/01046310): Aircraft › Aircraft propeller/rotor · Not inspected (probable cause); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-findings/01046310/cases.md?model=8059500), [All aircraft, 24 cases](https://openairdocs.org/ntsb-findings/01046310/cases.md) - [Inspection: preflight inspection](https://openairdocs.org/ntsb-findings/02061510): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-findings/02061510/cases.md?model=8059500), [All aircraft, 551 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md) - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=8059500), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) - [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=8059500), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md) - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=8059500), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Preflight or dispatch event](https://openairdocs.org/ntsb-events/030); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-events/030/sequence.md?model=8059500), [All aircraft, 355 cases](https://openairdocs.org/ntsb-events/030/sequence.md) - [Enroute-cruise: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=8059500), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=8059500), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-flare/touchdown: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=8059500), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-flare/touchdown: Roll over](https://openairdocs.org/ntsb-events/097); cases with it: [Schweizer HUGHES 269C, 1 case](https://openairdocs.org/ntsb-events/097/sequence.md?model=8059500), [All aircraft, 261 cases](https://openairdocs.org/ntsb-events/097/sequence.md) ## Analysis The pilot was conducting a personal flight when he heard a loud "snap" that was followed by a significant yaw of the helicopter during cruise flight. He stated that the throttle still controlled engine speed, but the main rotor speed did not respond to throttle changes. He immediately entered an autorotation and landed the helicopter level on its skids in a nearby wheat field. The helicopter still had forward ground speed at touchdown, it pitched up briefly, and then slowly rolled onto its right side. The pilot moved the mixture control into the fuel cutoff position to shut down the engine after the accident. The helicopter caught fire a few minutes after the accident and was subsequently destroyed. Postaccident examination revealed that the forward drive splines of the lower coupling drive shaft were missing and exhibited evidence of significant rotational damage. The pilot was unaware of the flight manual’s preflight checklist requirement to check the free-play and to verify the proper lubrication of the lower coupling drive shaft, nor had he ever completed those preflight inspection tasks during the 18 years that he had owned the helicopter. Had he completed an adequate preflight inspection of the helicopter, the pilot would have been aware of the lack of lubrication and/or excessive free-play of the lower coupling driveshaft and that maintenance was required before the helicopter could be flown safely. A review of available maintenance documentation revealed that the helicopter was not in compliance with an airworthiness directive that required the disassembly of the lower coupling drive shaft components for a recurring inspection. The helicopter had exceeded the initial 25-hour time-in-service inspection requirement by about 44 hours when the accident occurred. The pilot, who was the sole owner and operator of the helicopter, was responsible for ensuring compliance with the airworthiness directive. The pilot’s non-compliance with the required inspection contributed to the failure of the lower coupling drive shaft. ## Factual narrative On August 16, 2018, about 1030 central daylight time, a Schweizer 269C helicopter, N3625Z, was destroyed when it was involved in an accident near Kindred, North Dakota. The pilot was not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that while in cruise flight about 1,000 ft above the ground he heard a loud "snap" that was followed by a significant yaw of the helicopter. He immediately pushed the cyclic control forward and lowered the collective. He observed a "split needle" indication on the instrument panel gauge; the engine speed did not match main rotor speed. The throttle still controlled engine speed, but the main rotor speed did not respond to throttle changes. The pilot stated that the engine continued to run normally, and that yaw control was maintained through the antitorque pedals. He immediately entered an autorotation and made one revolution while he located a suitable landing area. The pilot landed the helicopter level on its skids in a nearby wheat field, but the helicopter still had forward ground speed and it pitched up briefly. The helicopter subsequently pitched down and slowly rolled onto its right side. The pilot moved the mixture control into the fuel cutoff position to shut down the engine after the accident. The pilot exited the helicopter without injury where he observed smoke emanating from the right side of the helicopter near the damaged right fuel tank. The helicopter caught fire a few minutes after the accident and was subsequently destroyed. The helicopter wreckage was examined by a Federal Aviation Administration (FAA) airworthiness inspector before it was recovered from the field. The FAA inspector reported that the forward drive splines of the lower coupling drive shaft were missing and exhibited evidence of significant rotational damage. The FAA Inspector interviewed the pilot to confirm what specific preflight inspection tasks were required with respect to the lower coupling drive shaft. The pilot was unaware of the helicopter’s flight manual preflight checklist requirement to check the free-play and verify the presence of adequate lubrication of the lower coupling drive shaft. The flight manual stipulates that maintenance be completed before the next flight if excessive free-play and/or lack of lubrication is observed to the lower coupling drive shaft during a preflight inspection. When the FAA Inspector demonstrated how to check the free-play and verify proper lubrication of the lower coupling drive shaft, the pilot stated that he had never completed those preflight inspection tasks during the 18 years that he had owned the helicopter. FAA Airworthiness Directive (AD) 93-17-13, dated October 20, 1993, required the disassembly of the lower coupling drive shaft components for inspection every 300 hours time-in-service. A review of the maintenance records and the pilot’s flight records revealed that the helicopter had accumulated about127 hours since AD No. 93-17-13 was last completed on September 5, 2013. Further review of the maintenance records revealed that the helicopter was not in compliance with AD No. 2017-14-06 that had replaced AD No. 93-17-13 on August 25, 2017. AD No. 2017-14-06 required the disassembly and inspection of the lower coupling drive shaft components within 25 hours time-in-service, and then every 150 hours time-in-service thereafter. The helicopter had never been inspected in accordance with AD No. 2017-14-06, and had exceeded the initial 25 hour time-in-service inspection requirement by about 44 hours when the accident occurred. ## Aircraft - Registration: [N3625Z](https://openairdocs.org/deregistered/N3625Z-2019-11-29), registration cancelled 2019-11-29, S/N S1194 (OpenAirDocs) - Reported make and model: Schweizer 269C - Registry model: [Schweizer HUGHES 269C](https://openairdocs.org/model/schweizer-hughes-269c) (registry code 8059500) (OpenAirDocs) - Category: Helicopter - Serial number: S1194 - Year built: 1985 - Airframe hours: 3474.5 - Engines: Lycoming HIO-360-A1A 190 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 1, 2017 - Departed: McLeod, ND - Destination: FAR, Fargo, ND ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 72; injuries: none; commercial; airplane ratings: single-engine land, single-engine sea; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review August 26, 2016; seat: left; restraint: 3-point; flight hours: 4,089.4 total, 930 in this make and model, 33 in the last 90 days, 12 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 57 °F - Altimeter: 30.01 inHg - Observed at: FAR, 17 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 20180816014339A](https://openairdocs.org/incident/20180816014339A), Aug 16, 2018: Schweizer HUGHES 269C, Kindred, ND, Destroyed. Pilot was flying level at 1000 AGL when he heard a loud snap. The aircraft yawed right and lost power to the main rotor. The pilot attempted to auto rotate… ## Other investigations on N3625Z (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 CHI93LA013](https://openairdocs.org/ntsb/CHI93LA013), Oct 22, 1992: Schweizer H-300 (N3625Z), Grand Forks, ND, substantial damage. Probable cause: THE PILOT'S FAILURE TO MAINTAIN CONTROL OF THE HELICOPTER DURING A NIGHT LANDING. ## Docket (8 files) The files NTSB released with the investigation on July 15, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=98084. 4.2 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 7 pages, 858 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12140282&FileExtension=pdf&FileName=01%20-%20Pilot%20Report_Redacted-Rel.pdf - Memorandum of conversation (thomas nagle) (item 2, PDF, 1 page, 74 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12140446&FileExtension=pdf&FileName=02%20-%20Memorandum%20of%20Conversation%20(Thomas%20Nagle)-Rel.pdf - FAA inspector statement and email message (item 3, PDF, 3 pages, 200 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12140502&FileExtension=pdf&FileName=03%20-%20FAA%20Inspector%20Statement%20and%20Email%20Message_Redacted-Rel.pdf - Maintenance logbooks (excerpts) (item 4, PDF, 5 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12140796&FileExtension=pdf&FileName=05%20-%20Maintenance%20Logbooks%20(Excerpts)_Redacted-Rel.pdf - FAA airworthiness directive 93-17-13 (item 5, PDF, 2 pages, 460 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12139715&FileExtension=pdf&FileName=06%20-%20FAA%20AD%2093-17-13-Rel.pdf - FAA airworthiness directive 2017-14-06 (item 6, PDF, 7 pages, 109 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12140272&FileExtension=pdf&FileName=07%20-%20FAA%20AD%202017-14-06-Rel.pdf - Weather data (item 7, PDF, 1 page, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12140574&FileExtension=pdf&FileName=09%20-%20Weather%20Data-Rel.pdf - Photos (item 8, PDF, 2 pages, 2 photos, 304 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12140814&FileExtension=pdf&FileName=10%20-%20Photos-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.