# NTSB LAX93LA306: Ayres S-2R-T34, N4016B, Tulare, CA, July 29, 1993

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 29, 1993, 07:20 local (14:20 UTC)
- Place: Tulare, CA
- Location: 36.1566° N, 119.3266° W: Placed by OpenAirDocs at MEFFORD FLD (TLR), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=36.1566&lon=-119.3266&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report September 26, 1994
- Report: Approved by Office Director
- NTSB case key (mKey): 28437
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX93LA306
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/28437/pdf
- Page: https://openairdocs.org/ntsb/LAX93LA306

## Probable cause

the failure of the main gear inner lower tube assembly due to fatigue.

## Sequence of events

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

- Main gear collapsed, taxi - to takeoff
  - landing gear,main gear attachment - failure,total (cause)
  - landing gear,main gear attachment - fatigue (cause)

## Analysis

THE PILOT HAD COMPLETED FOUR AERIAL APPLICATION FLIGHTS.  WHILE TAXIING OUT FOR THE FIFTH FLIGHT, THE LEFT MAIN LANDING GEAR COLLAPSED.  EXAMINATION OF THE MAIN GEAR STRUT REVEALED THAT THE INNER LOWER TUBE ASSEMBLY FRACTURED AT A BOLT HOLE DUE TO FATIGUE.

## Factual narrative

On July 29, 1993, at 0720 hours Pacific daylight time, an Ayres S-2R- T34, N4016B, left main gear collapsed, which ultimately damaged the left wing spar, while taxiing for takeoff at Tulare Airport, Tulare, California.  The pilot was beginning a local visual flight rules aerial application flight.  The airplane, operated by Moore Aviation, Tulare, sustained substantial damage.  The certificated commercial pilot, the sole occupant, was not injured.

The pilot reported in a telephone interview conducted on January 13, 1994, that he had completed four aerial application flights before beginning the accident flight.  Company maintenance personnel reported that the main gear strut lower inner tube assembly bolt hole cracked which ultimately led to the gear failure.  The cracked hole radius displayed extensive fatigue signatures.

## Aircraft

- Registration: [N4016B](https://openairdocs.org/aircraft/N4016B), registered now, S/N 6043 (OpenAirDocs)
- Reported make and model: AYRES S-2R-T34
- Registry model: [Ayres S2R-T34](https://openairdocs.org/model/ayres-s2r-t34) (registry code 0970106) (OpenAirDocs)
- Registry engine: [Pratt & Whitney Canada PT6A-60A](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-60a) (registry code 52043, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 6043
- Airframe hours: 7590
- Engines: P&W PT6A-34-AG 750 horsepower turbo prop
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Registered owner: Moore Aviation
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, March 1, 1993
- Airport: TLR, Medfford Field

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 7,248 total, 1,500 in this make and model, 167 in the last 90 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 320° at 7 knots
- Visibility: 12 statute miles
- Lowest ceiling: none
- Temperature: 68 °F, dew point 55 °F
- Altimeter: 30.00 inHg
- Observed at: FAT, 42 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 19930729026479A](https://openairdocs.org/incident/19930729026479A), Jul 29, 1993: Ayres S2RT34RESTD, Tulare, CA, Substantial damage. Left main landing gear collapsed taxiing for takeoff. Strut lower inner tube assembly bolt hole cracked due fatigue

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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