# NTSB FTW95LA279: Bellanca 8GCBC, N57669, Wellington, CO, July 8, 1995

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 8, 1995, 13:30 local (19:30 UTC)
- Place: Wellington, CO
- Coordinates: 40.699756, -105.000328 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.6998&lon=-105.0003&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report January 29, 1996
- Report: Approved by Office Director
- NTSB case key (mKey): 19482
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW95LA279
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/19482/pdf
- Page: https://openairdocs.org/ntsb/FTW95LA279

## Probable cause

FATIGUE FAILURE OF THE LEFT MAIN LANDING GEAR (SPRING STRUT), DUE TO THE IMPROPER MAINTENANCE (GRINDING) BY UNKNOWN MAINTENANCE PERSONNEL.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Gear collapsed, landing - roll
  - maintenance - improper, other maintenance personnel (cause)
  - landing gear,main gear strut - fatigue (cause)

## Analysis

DURING TOUCHDOWN FOR LANDING AT THE COMPLETION OF A GLIDER TOW FLIGHT, THE LEFT MAIN LANDING GEAR SEPARATED FROM THE AIRCRAFT, JUST OUTBOARD FROM THE FUSELAGE ATTACH POINT. EXAMINATION OF THE FRACTURE AREA REVEALED THAT THE SPRING GEAR HAD FAILED FROM FATIGUE. THERE WAS EVIDENCE THAT GRINDING HAD BEEN PERFORMED ON THE SPRING GEAR (DURING MAINTENANCE), WHICH RESULTED IN OVERHEATING OF THE STEEL AND SUBSEQUENT CHANGES IN ITS MICROSTRUCTURE.

## Factual narrative

On July 8, 1995, at 1330 mountain daylight time, a Bellanca 8GCBC, N57669, sustained substantial damage when the left main landing gear failed during landing roll at Owl Canyon Glider Park, Wellington, Colorado.  The commercial pilot was not injured.  Visual meteorological conditions prevailed for this local area glider tow flight operating under Title 14 CFR Part 91.  The flight originated at 1320 and a flight plan was not filed.

According to the pilot, his landing sequence following the glider release contained "a mild bounce."  The pilot said he added power for the second touch down and when touch down occurred the left main landing gear separated from the aircraft.

Examination of the aircraft by the investigator-in-charge provided evidence that the landing gear was of the spring steel type.  Separation occurred just outboard of the fuselage attach point and during the ground excursion following the separation, the left wing, wing strut, left elevator, wind screen, left side window and propeller sustained damage.

Examination of the fracture surface by the NTSB Metallurgical Laboratory provided evidence of a fatigue failure and evidence that the landing gear spring steel had been ground at some point in time which caused overheating of the steel and subsequent changes in the microstructure.  It was the metallurgist's evaluation, that the grinding initiated the fatigue.  The metallurgist's report is attached.

## Aircraft

- Registration: [N57669](https://openairdocs.org/aircraft/N57669), registered now, S/N 2-74, built 1974 (OpenAirDocs)
- Reported make and model: BELLANCA 8GCBC
- Registry model: [Bellanca 8GCBC](https://openairdocs.org/model/bellanca-8gcbc) (registry code 1220803) (OpenAirDocs)
- Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 2-74
- Airframe hours: 4692
- Engines: LYCOMING O-360-C2E 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 91
- Registered owner: Colorado Soaring Association
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 7, 1995, 35 hours before
- Departed: 4CO2
- Airport: 4C02, Owl Canyon Glider Park, runway 1, 2,000 × 40 ft, grass/turf

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: front; flight hours: 1,113 total, 207 in this make and model, 1,056 as pilot in command, 32 in the last 90 days, 10 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 10° at 6 knots, gusting 15
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 90 °F, dew point 37 °F
- Altimeter: 30.00 inHg
- Observed at: FNL, 15 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 19950708017229A](https://openairdocs.org/incident/19950708017229A), Jul 8, 1995: Bbavia 8GCBC, Wellington, CO, Substantial damage. Landing after glider tow. Left main gear separated. Grinding on surfaced had heated spring steel. Tensile affected.

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.

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