# NTSB WPR10LA171: Carr RV-4, N66PB, Arlington, WA, March 18, 2010

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: March 18, 2010, 14:55 local (21:55 UTC)
- Place: Arlington, WA
- Coordinates: 48.160556, -122.158889 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=48.1606&lon=-122.1589&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report July 18, 2011
- Report: Approved by Office Director
- NTSB office: Western Pacific Region
- Parties: FAA FSDO
- NTSB case key (mKey): 75552
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10LA171
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/75552/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=75552
- Page: https://openairdocs.org/ntsb/WPR10LA171

## Probable cause

The failure of both main landing gear's drag link bolts in overstress and the subsequent collapse of the landing gear during landing rollout.

## Findings

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

- [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Carr B L RV-4, 1 case](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=05606Y8), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/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: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Carr B L RV-4, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=05606Y8), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md)
- [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Carr B L RV-4, 2 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=05606Y8), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md)

## Analysis

The pilot said that when he took off and retracted the airplane's landing gear, only the tailwheel retracted. He lowered the landing gear and saw three green lights, indicating that all three landing gear were down and safe for landing. He then proceeded to his destination with the main landing gear down. During landing rollout at his destination, the left main landing gear collapsed. The airplane departed the left side of the runway before the right main landing gear collapsed as well. When the left wing's main landing gear collapsed outward, it damaged the wing structure and punctured the left fuel tank. The skin on the top of the right wing and the right aileron were wrinkled. Postaccident examination of the landing gear revealed that both main landing gear drag link bolts failed. These bolts were welded to the back of each main landing gear as part of their landing retraction system. Examination of photographs of the broken bolts by an NTSB metallurgist revealed that each bolt exhibited cantilever beam bending in overstress. The quality of the photographs was inadequate to determine if fatigue played a role.

## Factual narrative

On March 18, 2010, approximately 1455 Pacific daylight time, a Carr RV-4 experimental amateur-built airplane, N66PB, sustained substantial damage when the left main landing gear collapsed during landing rollout at the Arlington Municipal Airport, Arlington, Washington. The airline transport pilot, the sole occupant, was not injured. The owner/pilot was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the personal flight, which had originated from Burlington, Washington, approximately 1430. A flight plan had not been filed. The pilot said that when he took off and retracted the airplane's landing gear, only the tail wheel retracted. He lowered the landing gear, and got three green lights indicating that all three landing gear were down and safe for landing. He then proceeded to Arlington, where during the landing roll out on runway 34, the left main landing gear collapsed. The airplane departed the left side of the runway and subsequently the right main landing gear collapsed. When the left wing's main landing gear collapsed outward, it damaged the wing structure and punctured the left fuel tank. The skin on the top of the right wing and the right aileron were wrinkled. Postaccident examination of the landing gear revealed that both main landing gear drag link bolts failed. These bolts were welded to the back of each main landing gear as part of their landing retraction system. Examination of photographs of the broken bolts by an NTSB metallurgist revealed that each bolt exhibited cantilever beam bending in overstress. The quality of the photographs was inadequate to determine if fatigue played a role.

## Aircraft

- Registration: [N66PB](https://openairdocs.org/deregistered/N66PB-2019-06-18), registration cancelled 2019-06-18, S/N 2953, built 1995 (OpenAirDocs)
- Reported make and model: CARR RV-4
- Registry model: [Carr B L RV-4](https://openairdocs.org/model/carr-b-l-rv-4) (registry code 05606Y8) (OpenAirDocs)
- Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 2953
- Airframe hours: 635
- Engines: LYCOMING O&VO-360 SER 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Grover P. Best
- Registered owner: Grover P. Best
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Condition, November 3, 2009
- Departed: BVS, Burlington, WA
- Destination: AWO, Arlington, WA
- Flight plan: Unknown
- Airport: AWO, Arlington Municipal Arpt, runway 34, 5,332 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 69; injuries: none; airline transport, flight engineer; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review August 5, 2009; seat: front; flight hours: 20,000 total, 435 in this make and model, 12,000 as pilot in command, 6 in the last 90 days, 2 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 310° at 11 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 50 °F, dew point 37 °F
- Altimeter: 30.46 inHg
- Observed at: AWO

## 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 20100318029809A](https://openairdocs.org/incident/20100318029809A), Mar 18, 2010: Carr B L RV-4, Arlington, WA, Substantial damage. N66PB departed skgit regional airport (kbvs) returning to Arlington Municipal Airport (kawo). After take takeoff the pilot put the landing gear handle in the…

## Other investigations on N66PB (1)

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.

- [NTSB GAA18CA203](https://openairdocs.org/ntsb/GAA18CA203), Apr 6, 2018: Carr B L RV 4 (N66PB), Caldwell, ID, substantial damage. Probable cause: The failure of the weld on the airplane’s left main landing gear axle support strut during landing, which resulted in a loss of directional control.

## Docket (2 files)

The files NTSB released with the investigation on June 7, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=75552. 490 KB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 474 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347849&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Bolt Statement (item 2, .PDF, 15 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347850&FileExtension=.PDF&FileName=Bolt%20Statement-Redacted.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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.