# NTSB GAA18CA473: Vans RV6, N56LK, Greeley, CO, August 4, 2018

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Data collection · Final report
- Date: August 4, 2018, 11:30 local (17:30 UTC)
- Place: Greeley, CO
- Coordinates: 40.429721, -104.641387 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.4297&lon=-104.6414&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing: Abnormal runway contact](https://openairdocs.org/ntsb-events/090)
- Highest injury: Serious injuries
- Injuries: 1 serious, 1 minor
- Status: Completed, report March 18, 2019
- Report: Approved by Office Director
- NTSB office: General Aviation Accidents
- Parties: FAA
- NTSB case key (mKey): 98009
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA18CA473
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/98009/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=98009
- Page: https://openairdocs.org/ntsb/GAA18CA473

## Probable cause

The pilot’s exceedance of the airplane’s critical angle of attack during approach, which resulted in an aerodynamic stall.

## Findings

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

- [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Klingmuller Lothar M L RV-6A, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=05611LB), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md)
- [Performance/control parameters: angle of attack](https://openairdocs.org/ntsb-findings/01062042): Aircraft › Aircraft oper/perf/capability · Capability exceeded (probable cause); cases with it: [Klingmuller Lothar M L RV-6A, 1 case](https://openairdocs.org/ntsb-findings/01062042/cases.md?model=05611LB), [All aircraft, 990 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md)

## Sequence of events

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

- [Landing: Miscellaneous/other](https://openairdocs.org/ntsb-events/900); cases with it: [Klingmuller Lothar M L RV-6A, 1 case](https://openairdocs.org/ntsb-events/900/sequence.md?model=05611LB), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md)
- [Landing: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Klingmuller Lothar M L RV-6A, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=05611LB), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md)
- [Landing: Abnormal runway contact](https://openairdocs.org/ntsb-events/090) (defining event); cases with it: [Klingmuller Lothar M L RV-6A, 1 case](https://openairdocs.org/ntsb-events/090/sequence.md?model=05611LB), [All aircraft, 1,506 cases](https://openairdocs.org/ntsb-events/090/sequence.md)

## Analysis

The pilot reported that, during approach, the airplane encountered the usual amount of sink, so he added power but applied too much back stick. The airplane aerodynamically stalled, landed hard, and then came to rest 1,500 ft down the runway. The airplane sustained substantial damage to the right wing and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

## Factual narrative

The pilot reported that, during approach, he airplane encountered the usual amount of sink, he added power, but applied too much back stick. The airplane aerodynamically stalled, landed hard, and the airplane came to rest 1,500 ft down the runway. The airplane sustained substantial damage to the right wing and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

## Aircraft

- Registration: [N56LK](https://openairdocs.org/aircraft/N56LK), registered now, S/N 123, built 2001 (OpenAirDocs)
- Reported make and model: Vans RV6 (A)
- Registry model: [Klingmuller Lothar M L RV-6A](https://openairdocs.org/model/klingmuller-lothar-m-l-rv-6a) (registry code 05611LB) (OpenAirDocs)
- Registry engine: [Lycoming O-360-A1A](https://openairdocs.org/engine/lycoming-o-360-a1a) (registry code 41594, 4 cycle) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 123
- Year built: 2001
- Airframe hours: 1300
- Engines: Lycoming O-360-A1A 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Condition, May 1, 2018
- Departed: FTG, Denver, CO
- Destination: GXY, Greeley, CO
- Airport: GXY, Greeley-Weld County, runway 10, 5,801 × 100 ft, asphalt
- Equipment: ADS-B, Auto-pilot, Handheld GPS

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 85; injuries: serious; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, without waivers/limitations; last flight review August 30, 2016; seat: left; restraint: 3-point; flight hours: 6,866.3 total, 25.7 in this make and model, 6,393.6 as pilot in command, 25.7 in the last 90 days, 4.1 in the last 30 days, 0.6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 90 °F, dew point 50 °F
- Altimeter: 30.01 inHg
- Observed at: KGXY, 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 20180804010009A](https://openairdocs.org/incident/20180804010009A), Aug 4, 2018: Klingmuller Lothar M L RV-6A, Greeley, CO, Substantial damage. Flight departed front range airport (ftg) for Greeley, CO (gxy) at approximately 10:50 am local time on 8/4/2018. The builder of the aircraft had put the…

## Docket (2 files)

The files NTSB released with the investigation on October 31, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=98009. 1.0 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 665 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467870&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF
- Accident Photo (item 2, .PDF, 1 photo, 365 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467871&FileExtension=.PDF&FileName=Accident%20Photo-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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