# NTSB ERA12LA431: Leder John A Leder Velocity XL RG, N224SM, Thomson, GA, July 2, 2012

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 2, 2012, 17:45 local (21:45 UTC)
- Place: Thomson, GA
- Coordinates: 33.529724, -82.516944 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.5297&lon=-82.5169&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report May 9, 2013
- Report: Approved by Office Director
- NTSB office: Eastern Region Aviation
- Parties: FAA Atlanta FSDO
- NTSB case key (mKey): 84213
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA12LA431
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/84213/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=84213
- Page: https://openairdocs.org/ntsb/ERA12LA431

## Probable cause

Separation of the nose landing gear due to a preexisting fatigue crack caused by an earlier shimmy event and the subsequent incorrect installation of the shimmy dampener.

## Findings

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

- [Landing gear system: nose/tail gear strut/axle](https://openairdocs.org/ntsb-findings/01023222): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Leder John A LEDER VELOCITY XL RG, 1 case](https://openairdocs.org/ntsb-findings/01023222/cases.md?model=05610IL), [All aircraft, 36 cases](https://openairdocs.org/ntsb-findings/01023222/cases.md)
- [Landing gear system: shimmy damper](https://openairdocs.org/ntsb-findings/01023252): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Leder John A LEDER VELOCITY XL RG, 1 case](https://openairdocs.org/ntsb-findings/01023252/cases.md?model=05610IL), [All aircraft, 3 cases](https://openairdocs.org/ntsb-findings/01023252/cases.md)
- [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Not specified (probable cause); cases with it: [Leder John A LEDER VELOCITY XL RG, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=05610IL), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/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) (defining event); cases with it: [Leder John A LEDER VELOCITY XL RG, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=05610IL), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md)
- [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Leder John A LEDER VELOCITY XL RG, 1 case](https://openairdocs.org/ntsb-events/094/sequence.md?model=05610IL), [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: [Leder John A LEDER VELOCITY XL RG, 1 case](https://openairdocs.org/ntsb-events/300/sequence.md?model=05610IL), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md)

## Analysis

The pilot stated that he landed the airplane on the main landing gear and then lowered the nose landing gear on the runway. The nosewheel started to shimmy, and the pilot applied aft pressure on the control yoke; however, the nose landing gear strut assembly subsequently separated from the airplane and the airplane veered right and came to rest in the grass off the right side of the runway. The pilot further stated that he had experienced a shimmy event about 50 flight hours before the accident, and he decided to install a shimmy dampener on the airplane. Metallurgical examination of the components revealed the nose landing gear separated due to a preexisting fatigue crack caused by the earlier shimmy event and the subsequent incorrect installation of the shimmy dampener. Specifically, the shimmy dampener alignment pin had not been installed, which rendered the shimmy dampener ineffective.

## Factual narrative

On July 2, 2012, at 1745 eastern daylight time, an experimental amateur-built Velocity XL RG airplane, N224SM, experienced a separation of the nose landing gear strut on landing roll out at Thomson-McDuffie County Airport (HQU), Thomson, Georgia. The airplane was registered to a private owner and was operating as a 14 Code of Federal Regulations Part 91 personal flight. The airplane sustained substantial damage. Visual meteorological conditions prevailed and no flight plan was filed. The private pilot reported no injuries. The flight originated from Elkins-Randolph County Airport,(EKN), Elkins, West Virginia, at 1535. The pilot stated he landed on the main landing gear and lowered the nose landing gear on the runway. The nose wheel started to shimmy and he applied aft pressure on the control yoke with negative results. The nose of the airplane pitched down on the runway centerline. He steered the airplane off the right side of the runway into the grass and performed an emergency shutdown. When he exited the airplane he observed the nose landing gear yoke and strut had separated and was on the runway. The pilot further stated that he had experienced a shimmy event about 50 hours prior to the accident, and he decided to install the shimmy dampener on the airplane. The nose landing gear strut assembly fractured into two pieces. The pieces were sent to the NTSB Materials Laboratory, Washington, DC, for metallurgical examination. Examination of the components revealed the nose landing gear collapsed due to a preexisting fatigue crack, consistent with a prior shimmy event and incorrect installation of the shimmy dampener. Specifically, there was no evidence that the shimmy dampener alignment pin was installed. There were no signs of mechanical deformation in the pinhole where the dampener shaft and the fork are coupled by the alignment pin that passes through the pinhole and engages a slot in the fork. Without the alignment pin installed, the rotations of the fork and the dampener shaft were not coupled and the shimmy was not dampened out.

## Aircraft

- Registration: [N224SM](https://openairdocs.org/aircraft/N224SM), registered now, S/N 001, built 2000 (OpenAirDocs)
- Reported make and model: LEDER JOHN A LEDER VELOCITY XL RG
- Registry model: [Leder John A LEDER VELOCITY XL RG](https://openairdocs.org/model/leder-john-a-leder-velocity-xl-rg) (registry code 05610IL) (OpenAirDocs)
- Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 001
- Airframe hours: 389
- Engines: LYCOMING O-540-E4C5 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Mueller Terry L
- Registered owner: Mueller Terry L
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Condition, December 29, 2011, 90 hours before
- Departed: EKN, Elkin, WV
- Destination: HQU, Thomson, GA
- Airport: HQU, Thomson-McDuffie, runway 10, 5,503 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review October 5, 2011; seat: left; flight hours: 262 total, 159 in this make and model, 224 as pilot in command, 62 in the last 90 days, 14 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 70° at 3 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 93 °F, dew point 70 °F
- Altimeter: 30.01 inHg
- Observed at: HQU

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 20120702017969I](https://openairdocs.org/incident/20120702017969I), Jul 2, 2012: Leder John A LEDER VELOCITY XL RG, Thomson, GA, Minor damage. From witness accounts the aircraft, N224SM, upon landing, the main nose landing gear began to shimmy to the point where the nose main landing gear separated…

## Docket (14 files)

The files NTSB released with the investigation on March 20, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=84213. 16.7 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 4.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372374&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Materials Laboratory 15 - Factual Report 12-095 (with 6 embedded images) (item 2, .PDF, 848 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40381142&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2012-095%20(with%206%20embedded%20images)-Master.PDF
- UPS Wreckage Release From HQ Materials Lab (item 3, .PDF, 199 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40376912&FileExtension=.PDF&FileName=UPS%20Wreckage%20Release%20From%20HQ%20Materials%20Lab-Redacted.PDF
- Photo 1 View of marks on runway 10 where accident airplane departed right side of runway. Photo owner. (item 4, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372267&FileExtension=.PDF&FileName=Photo%201%20View%20of%20marks%20on%20runway%2010%20where%20accident%20airplane%20departed%20right%20side%20of%20runway.%20Photo%20owner.-Master.PDF
- Photo 2 Front view of airplane at rest. Photo owner (item 5, .PDF, 865 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372268&FileExtension=.PDF&FileName=Photo%202%20Front%20view%20of%20airplane%20at%20rest.%20Photo%20owner-Master.PDF
- Photo 3 Left side view of airplane at rest. Photo owner (item 6, .PDF, 912 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372269&FileExtension=.PDF&FileName=Photo%203%20Left%20side%20view%20of%20airplane%20at%20rest.%20Photo%20owner-Master.PDF
- Photo 4 Rear view of airplane. Photo owner (item 7, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372270&FileExtension=.PDF&FileName=Photo%204%20Rear%20view%20of%20airplane.%20Photo%20owner-Master.PDF
- Photo 5 Right side view of airplane. Photo owner (item 8, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372271&FileExtension=.PDF&FileName=Photo%205%20Right%20side%20view%20of%20airplane.%20Photo%20owner-Master.PDF
- Photo 6 View of separated nose landing gear strut. Photo owner (item 9, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372272&FileExtension=.PDF&FileName=Photo%206%20View%20of%20separated%20nose%20landing%20gear%20strut.%20Photo%20owner-Master.PDF
- Photo 7 View of opposite end of separated nose landing gear strut. Photo owner (item 10, .PDF, 960 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372273&FileExtension=.PDF&FileName=Photo%207%20View%20of%20opposite%20end%20of%20separated%20nose%20landing%20gear%20strut.%20Photo%20owner-Master.PDF
- Photo 8 View of separated nose landing gear. Photo owner (item 11, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372274&FileExtension=.PDF&FileName=Photo%208%20View%20of%20separated%20nose%20landing%20gear.%20Photo%20owner-Master.PDF
- Photo 9 View of shimmy dampener with upper plate modified by owner to capture the top of the pivot pin. Photo owner (item 12, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372275&FileExtension=.PDF&FileName=Photo%209%20View%20of%20shimmy%20dampener%20with%20upper%20plate%20modified%20by%20owner%20to%20capture%20the%20top%20of%20the%20pivot%20pin.%20Photo%20owner-Master.PDF
- Photo 10 view of skin damage to fuselage. Photo owner (item 13, .PDF, 947 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372276&FileExtension=.PDF&FileName=Photo%2010%20view%20of%20skin%20damage%20to%20fuselage.%20Photo%20owner-Master.PDF
- Photo 11 Another view of skin damage to fuselage. Photo owner (item 14, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40372277&FileExtension=.PDF&FileName=Photo%2011%20Another%20view%20of%20skin%20damage%20to%20fuselage.%20Photo%20owner-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.

---
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.