# NTSB CHI94LA013: Hughes 269A, N7032U, Coldwater, MI, October 12, 1993 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 12, 1993, 16:45 local (20:45 UTC) - Place: Coldwater, MI - Coordinates: 41.939693, -84.999031 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.9397&lon=-84.9990&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report October 20, 1994 - Report: Approved by Office Director - ADs cited in the narratives: [AD 88-17-04](https://openairdocs.org/ad/88-17-04), [AD 76-18-01](https://openairdocs.org/ad/76-18-01) (OpenAirDocs) - NTSB case key (mKey): 9412 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI94LA013 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/9412/pdf - Page: https://openairdocs.org/ntsb/CHI94LA013 ## Probable cause the fatigue failure of the tailboom support strut attachment lug. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, hover - fuselage,attachment - fatigue (cause) - Loss of control - in flight, hover - rotor drive system,tail rotor drive shaft - sheared - directional control - not possible, dual student - autorotation - performed, dual student ## Analysis The certificated helicopter pilot who was receiving dual instruction was at the controls in a hover. The pilot and the CFI both reported hearing a bang followed by loss of directional control. The student pilot made a successful hovering autorotation. The investigation revealed the tailboom support strut attachment lug had failed at the left aft cluster fitting. The failed part was examined and found to have failed due to fatigue. ## Factual narrative On October 12, 1993, at 1645 eastern daylight time, a Hughes 269A, N7032U, operated by Brooks Aero, Inc., Marshall, Michigan, sustained substantial damage when it had an in-flight structural failure, while in a hover at the Branch County Airport, Coldwater, Michigan. Neither the certified flight instructor, nor the private certificated student pilot were injured. The instructional flight originated at Brooks Field, Marshall, Michigan. No flight plan was filed, and visual meteorological conditions prevailed at the time. The investigation found the left tailboom support strut attachment lug on the left aft cluster fitting (P/N 269A2234) had failed. A witness reported the tailboom was moving up and down just before the accident. The tailboom was hit and severed by the main rotor system. The dual student, who was at the controls, made a successful hovering autorotative landing without additional damage to the helicopter. The helicopter log book shows the last inspection was a 100 hour inspection performed on June 22, 1993. The helicopter has logged 65 hours since the inspection. The log book entry records compliance with Airworthiness Directives 88-17-04 and 76-18-01 which pertain to the cluster fittings. The failed support strut attachment lug was sent to the NTSB Materials Laboratory, Washington, D.C., for examination. The laboratory reported the presence of fatigue fracture features on both ears of the attachment lug. ## Aircraft - Registration: [N7032U](https://openairdocs.org/deregistered/N7032U-2014-12-03), registration cancelled 2014-12-03, S/N 1140327 (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: 114-0327 - Airframe hours: 4695 - Engines: LYCOMING HIO-360-B1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Brooks Aero, Inc. - Registered owner: Shallow Corp. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 22, 1993, 65 hours before - Departed: 5D8, MARSHALL, MI - Airport: D96, Branch County Memorial ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 25; flight instructor, airline transport, commercial; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 1,750 total, 1,500 as pilot in command, 240 in the last 90 days, 40 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 10 knots - Visibility: 12 statute miles - Lowest ceiling: 2,900 ft broken - Temperature: 68 °F, dew point 54 °F - Altimeter: 29.00 inHg - Observed at: BTL, 24 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 19931012038699A](https://openairdocs.org/incident/19931012038699A), Oct 12, 1993: Hughes 269B, Coldwater, MI, Substantial damage. During dual flight. Left rear tailboom support structure attach. Cluster itting broke. Rotors struck tailboom. 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.