# NTSB DEN02LA098: Schweizer 269C, N7508L, Broomfield, CO, August 20, 2002 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 20, 2002, 11:20 local (17:20 UTC) - Place: Broomfield, CO - Coordinates: 39.908611, -105.117225 - Nearby events: https://openairdocs.org/map.md?lat=39.9086&lon=-105.1172&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 16, 2003 - Report: Approved by Office Director - Parties: FAA Flight Standards District Office - NTSB case key (mKey): 55562 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN02LA098 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/55562/pdf - Page: https://openairdocs.org/ntsb/DEN02LA098 ## Probable cause maintenance personnel's failure to secure the landing skid oleo strut bolt during the last 50-hour inspection, causing the left rear skid to collapse and the tail rotor to strike the ground. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, standing - engine(s) operating - miscellaneous,bolt/nut/fastener/clamp/spring - not secured (cause) - maintenance,100-hour inspection - inadequate, other maintenance personnel (cause) - landing gear,skid assembly - collapsed - rotor drive system,tail rotor drive shaft - twisted ## Analysis The student was practicing autorotations in preparation for taking his rotorcraft-helicopter practical flight test the following day. With his instructor on board, the student had successfully performed two "full down" autorotations. As he completed the third autorotation, they heard a loud noise and the helicopter settled toward the left rear, enough that the tail rotor struck the asphalt taxiway. Postaccident inspection disclosed that the bolt that attaches the left rear oleo strut to the crossbeam was missing. The tail rotor blades were damaged, the tail rotor driveshaft was twisted, and the splined end was separated from the main transmission. Maintenance records indicated the helicopter had accrued 5.1 hours since the last 50-hour inspection, at which time the landing gear struts had been overhauled and the skid shoes replaced. ## Factual narrative On August 20, 2002, approximately 1120 mountain daylight time, a Schweizer 269C, N7508L, operated by Rotors of the Rockies, was substantially damaged when the left rear landing skid collapsed during a practice autorotation at Jefferson County Airport, Broomfield, Colorado. The commercial pilot receiving instruction and the commercial flight instructor were not injured. Day visual meteorological conditions prevailed at the time, and no flight plan had been filed for the instructional flight being conducted under Title 14 CFR Part 91. The flight originated at Broomfield at an undetermined time. According to the flight instructor's accident report, the student was practicing autorotations in preparation for taking his rotorcraft-helicopter practical flight test the following day. They had successfully performed two "full down" autorotations. As the student completed the third autorotation, they heard a loud noise and the helicopter settled toward the left rear, enough that the tail rotor struck the asphalt taxiway. Postaccident inspection disclosed that the bolt that attaches the left rear oleo strut to the crossbeam was missing. The tail rotor blades were damaged, the tail rotor driveshaft was twisted, and the splined end was separated from the main transmission. The skids and fuselage bottom were not damaged. According to maintenance records, the helicopter had accrued 5.1 hours since the last 50-hour inspection, at which time the landing gear struts had been overhauled and the skid shoes replaced. ## Aircraft - Registration: [N7508L](https://openairdocs.org/aircraft/N7508L), registered now, S/N S1417, built 1989 (OpenAirDocs) - Reported make and model: Schweizer 269C - Registry model: [Schweizer 269C](https://openairdocs.org/model/schweizer-269c) (registry code 8059502) (OpenAirDocs) - Registry engine: [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series) (registry code 41524, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: S1417 - Airframe hours: 5598 - Engines: Lycoming HIO-360-D1A 190 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Rotors of the Rockies - Registered owner: Horton Cattle Company - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, August 16, 2002, 5 hours before - Departed: BJC, Broomfield, CO - Destination: BJC, Broomfield, CO - Airport: BJC, Jeffco ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 34; injuries: none; commercial, flight instructor; instrument ratings: helicopter; medical: class 1, valid medical--no waivers/lim.; last flight review June 16, 2002; seat: left; flight hours: 2,218 total, 707 in this make and model, 1,109 as pilot in command, 202 in the last 90 days, 83 in the last 30 days, 1 in the last 24 hours - Pilot; age 33; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; last flight review January 14, 2002; seat: right; flight hours: 1,827 total ## Weather - Conditions: Visual (VMC), Day - Wind: 70° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: 8,000 ft broken - Temperature: 86 °F, dew point 50 °F - Altimeter: 29.95 inHg - Observed at: BJC ## 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 20020820023469A](https://openairdocs.org/incident/20020820023469A), Aug 20, 2002: Hughes 269C, Denver, CO, Substantial damage. (-23) Aircraft was doing auto rotation instruction. Two auto-rotations had been done previously, on the day of the accident. As the aircraft was slowing and… 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.