# NTSB CHI91LA157: Piper PA-34-220T, N8356B, Eau Claire, WI, May 14, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 14, 1991, 16:00 local (21:00 UTC)
- Place: Eau Claire, WI
- Location: 44.8658° N, 91.4843° W: Placed by OpenAirDocs at CHIPPEWA VALLEY RGNL (EAU), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=44.8658&lon=-91.4843&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report February 8, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 15066
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI91LA157
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15066/pdf
- Page: https://openairdocs.org/ntsb/CHI91LA157

## Probable cause

THE INADEQUATE FINISHING PROCEDURES USED BY THE MANUFACTURER AND THE FAILURE TO COMPLY WITH THE MANUFACTURER'S BULLETIN.

## Sequence of events

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

- Main gear collapsed, landing - roll
  - landing gear,main gear strut - fatigue
  - maintenance,service bulletin/letter - not followed (cause)
  - procedure inadequate, manufacturer (cause)

## Analysis

THE RIGHT MAIN LANDING GEAR COLLAPSED DURING THE LANDING ROLL. THE AIRPLANE VEERED TO THE RIGHT AND THE RIGHT WING CONTACTED A RUNWAY LIGHT. POST ACCIDENT INVESTIGATION REVEALED A FATIGUE FAILURE OF THE LANDING GEAR TRUNNION ON THE LOWER FILLET OF THE WEB ON THE TRUNNION. METALLURGICAL EXAM REVEALED THE FAILURE PROPAGATED FROM GRINDING MARKS MADE DURING THE MANUFACTURING FINISHING PROCESS. A SERVICE BULLETIN WAS ISSUED IN 1985 BY THE MANUFACTURER ADDRESSING THE INSPECTION OF THIS AREA FOR CRACKS.

## Aircraft

- Registration: N8356B (not matched to a registry record)
- Reported make and model: PIPER PA-34-220T
- Category: Airplane
- Serial number: 34-8133D38
- Engines: CONTINENTAL TSIO-360-KB 220 horsepower reciprocating
- Damage: Substantial damage
- Flight: Business, Part 91
- Operator: Rojo
- Registered owner: Rojo
- Departed: ALO, WATERLOO, IA
- Flight plan: IFR
- Airport: EAU, Eau Claire Co, runway 32, 4,999 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 30; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; flight hours: 2,900 total, 75 in this make and model, 2,800 as pilot in command, 81 in the last 90 days, 27 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 150° at 7 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F
- Observed at: EAU, 1 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 19910514015739A](https://openairdocs.org/incident/19910514015739A), May 14, 1991: Piper PA34200T, Eau Claire, WI, Substantial damage. Right main landing gear failed during landing roll. Trunion had failed from fatigue. Service bulletin dated 1985.

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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