# NTSB BFO90LA069: Cessna 170B, N8239A, Frederick, MD, August 16, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 16, 1990, 15:30 local (19:30 UTC)
- Place: Frederick, MD
- Coordinates: 39.420688, -77.410949 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.4207&lon=-77.4109&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report December 30, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 11609
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO90LA069
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/11609/pdf
- Page: https://openairdocs.org/ntsb/BFO90LA069

## Probable cause

FATIGUE FAILURE OF THE LEFT MAIN GEAR WHEEL AXLE.

## Sequence of events

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

- Main gear collapsed, landing
  - landing gear,axle - fractured (cause)
  - landing gear,axle - fatigue (cause)

## Analysis

THE PLT WAS DOING HIS ELEVENTH TOUCH AND GO LANDING WHEN THE LEFT MAIN GEAR AXLE FAILED DURING THE LANDING ROLL, CAUSING THE ACFT TO GROUND LOOP. EXAMINATION OF THE ACFT REVEALED THE AXLE WAS FRACTURED AT ITS FLANGE JUNCTION. METALLURGICAL EXAMINATION REVEALED FATIGUE CORROSION ON THE FRACTURE SURFACE.

## Aircraft

- Registration: [N8239A](https://openairdocs.org/deregistered/N8239A-2013-08-05), registration cancelled 2013-08-05, S/N 25091, built 1952 (OpenAirDocs)
- Reported make and model: CESSNA 170B
- Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs)
- Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 25091
- Airframe hours: 3200
- Engines: FRANKLIN O-300 163 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Jon R. Shomer, Jr
- Airworthiness certificate: Standard, Normal
- Last inspection: Unknown, April 23, 1990, 0 hours before
- Departed: FDK
- Destination: FDK
- Airport: FDK, Frederick, runway 23, 5,200 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 22; student; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 45 total, 13 in this make and model, 13 in the last 90 days, 1 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 150° at 5 knots
- Visibility: 7 statute miles
- Lowest ceiling: none
- Temperature: 82 °F, dew point 64 °F
- Altimeter: 30.10 inHg
- Observed at: MRB, 28 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 19900816033219A](https://openairdocs.org/incident/19900816033219A), Aug 16, 1990: Cessna 170B, Frederick, MD, Substantial damage. Left main gear axle broke on landing causing a ground loop.

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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