# NTSB CEN16LA101: Aeronca O-58B, N47185, Bulverde, TX, January 31, 2016

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: January 31, 2016, 11:00 local (17:00 UTC)
- Place: Bulverde, TX
- Coordinates: 29.739166, -98.45111 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=29.7392&lon=-98.4511&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report October 3, 2016
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: Federal Aviation Administration, San Antonio FSDO
- NTSB case key (mKey): 92699
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN16LA101
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/92699/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=92699
- Page: https://openairdocs.org/ntsb/CEN16LA101

## Probable cause

The failure of the left main landing gear wheel casting due to fatigue, which resulted in a loss of directional control during the landing roll.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Landing gear system: wheel/ski/float](https://openairdocs.org/ntsb-findings/01023246): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Aeronca 0-58B, 1 case](https://openairdocs.org/ntsb-findings/01023246/cases.md?model=0191006), [All aircraft, 48 cases](https://openairdocs.org/ntsb-findings/01023246/cases.md)
- [Landing gear system: wheel/ski/float](https://openairdocs.org/ntsb-findings/01023246): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Aeronca 0-58B, 1 case](https://openairdocs.org/ntsb-findings/01023246/cases.md?model=0191006), [All aircraft, 48 cases](https://openairdocs.org/ntsb-findings/01023246/cases.md)
- [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Aeronca 0-58B, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=0191006), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330); cases with it: [Aeronca 0-58B, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=0191006), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md)
- [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Aeronca 0-58B, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=0191006), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md)
- [Landing-landing roll: Dragged wing/rotor/float/other](https://openairdocs.org/ntsb-events/093); cases with it: [Aeronca 0-58B, 1 case](https://openairdocs.org/ntsb-events/093/sequence.md?model=0191006), [All aircraft, 319 cases](https://openairdocs.org/ntsb-events/093/sequence.md)

## Analysis

The commercial pilot reported that, following a normal touchdown and during the landing roll, the airplane suddenly veered to the left. The pilot corrected for the left swerve with the application of right rudder and brake. The airplane subsequently entered a right swerve. The airplane did not respond to the pilot's application of left rudder and brake inputs. The pilot reported that there was a 15-ft descending embankment and trees off the right side of the runway and that, to avoid a runway excursion, he lowered the left wing and intentionally ground looped the airplane to the right. The left wing subsequently contacted the runway surface. A postaccident examination revealed a fracture to the left main landing gear wheel casting. The wheel fracture was located along the inner bearing race shelf and resulted in the bearing being exposed. The bearing race flange had fractured circumferentially and radially in two places. Further examination of the fracture surfaces revealed areas of fatigue, which were the result of casting oxide imperfections that had been present since the wheel was cast and had developed under typical loading of the landing gear. Additionally, the observed alternating fracture features were consistent with spectrum loading, typical of those experienced by a landing gear wheel. Ultimately, the wheel failed as a result of progressive fatigue cracking. The wheel had been cast in 1942, and the owner reported that the airplane had accumulated 3,520 hours since new with 10 hours since the last inspection.

## Factual narrative

On January 31, 2016, about 1100 central standard time, an Aeronca model O-58B single-engine airplane, N47185, was substantially damaged while landing at Bulverde Airpark (1T8), Bulverde, Texas. The commercial pilot and passenger were not injured. The airplane was registered to and operated by Assend Dragon Aviation, LLC under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight without a flight plan. Day visual meteorological conditions (VMC) prevailed at the time of the accident. The local area flight departed 1T8 at 1055.According to the pilot, the accident occurred during the second full-stop landing to runway 16 (2,890 feet by 40 feet, asphalt). The pilot reported that following a normal touchdown, during the landing roll, the airplane suddenly veered to the left. The pilot corrected for the left swerve with the application of right rudder and brake. The airplane subsequently entered a right swerve. The pilot stated that the airplane did not respond to his application of left rudder and brake inputs. The pilot reported that there was a 15 foot descending embankment and trees situated off the right side of the runway. He stated that, in order to avoid a runway excursion, he lowered the left wing and intentionally ground looped the airplane to the right. The left wing contacted the runway surface during the ground loop. At 1051, the automated surface observing system (ASOS) at the San Antonio International Airport (SAT), located about 12 miles south of the accident site, reported: wind 230 degrees at 4 knots, surface visibility 10 statute miles, few clouds at 2,000 feet above ground level, temperature 19 degrees Celsius, dew point 14 degrees Celsius, and an altimeter setting of 29.88 inches of mercury. The pilot reported that the wind condition had been light-and-variable during the accident flight. A postaccident inspection revealed substantial damage to the left wing's forward and rear spars. An additional inspection revealed a fracture to the left main landing gear wheel casting. The wheel fracture was located along the inner bearing race shelf and resulted in the bearing being exposed. The left tire tread did not exhibit any abnormal wear or scuffing. The wheel had been cast in 1942, and the owner reported that the airplane had accumulated 3,520 hours since new, with 10 hours since the last inspection. The fractured wheel was submitted to the National Transportation Safety Board (NTSB) Materials Laboratory for additional examination. The prepared laboratory report indicated that the bearing race flange had fractured circumferentially, as well as radially in two places. Further examination of the fracture surfaces revealed areas of fatigue that were the result of casting oxide imperfections that had developed under typical loading of the landing gear. The observed oxide imperfections would have been present since the wheel was cast. Additionally, the observed alternating fatigue and overstress features would beconsistent with spectrum loading, typical of those experienced by a landing gear wheel. Ultimately, the wheel failed as a result of progressive fatigue cracking.

## Aircraft

- Registration: [N47185](https://openairdocs.org/aircraft/N47185), registered now, S/N 058B-11123, built 1943 (OpenAirDocs)
- Reported make and model: AERONCA O-58B
- Registry model: [Aeronca 0-58B](https://openairdocs.org/model/aeronca-0-58b) (registry code 0191006) (OpenAirDocs)
- Registry engine: [Continental A&C65 series](https://openairdocs.org/engine/continental-a-c65-series) (registry code 17003, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 058B-11123
- Year built: 1943
- Airframe hours: 3520
- Engines: Continental C85-12F 85 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Assend Dragon Aviation, LLC
- Registered owner: Assend Dragon Aviation, LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, August 2, 2015, 17 hours before
- Departed: 1T8, Bulverde, TX
- Destination: 1T8, Bulverde, TX
- Airport: 1T8, Bulverde Airpark, runway 16, 2,890 × 40 ft, asphalt
- Equipment: Handheld GPS

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 64; injuries: none; flight instructor, commercial; airplane ratings: multi-engine sea, single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, waiver time limited special; last flight review January 27, 2016; seat: rear; restraint: lap only; flight hours: 2,556 total, 109 in this make and model, 2,419 as pilot in command, 18 in the last 90 days, 13 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 230° at 4 knots
- Visibility: 10 statute miles
- Temperature: 66 °F, dew point 57 °F
- Altimeter: 29.87 inHg
- Observed at: KSAT, 12 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 20160131008139A](https://openairdocs.org/incident/20160131008139A), Jan 31, 2016: Aeronca 0-58B, Bulverde, TX, Substantial damage. Upon landing on rollout left wheel assy hub broke loose from axle, causing acft to veer left, pilot attempted to correct aircraft direction by applying right…

## Docket (3 files)

The files NTSB released with the investigation on July 27, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=92699. 5.6 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 923 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40442631&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF
- Materials Laboratory Factual Report (item 2, .PDF, 13 photos, 4.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40442632&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report-Master.PDF
- Weather Reports (item 3, .PDF, 41 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40442633&FileExtension=.PDF&FileName=Weather%20Reports-Master.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.

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