# NTSB WPR21LA176: Vans RV4, N345DL, Oljato-Monument Valley, UT, April 15, 2021

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Class 4 · Limited · Final report
- Date: April 15, 2021, 13:58 local (19:58 UTC)
- Place: Oljato-Monument Valley, UT
- Coordinates: 37.01752, -110.20223 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=37.0175&lon=-110.2022&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach-VFR pattern final: Loss of control in flight](https://openairdocs.org/ntsb-events/240)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Western Pacific Region
- Parties: FAA
- NTSB case key (mKey): 102978
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA176
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102978/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102978
- Page: https://openairdocs.org/ntsb/WPR21LA176

## Probable cause

The pilot’s failure to maintain airplane control while compensating for a downdraft during landing, which resulted in the airplane touching down short of the runway on soft terrain and nosing over.

## 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: [Leeper Damon L RV-4, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=05608CK), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md)
- [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Ability to respond/compensate; cases with it: [Leeper Damon L RV-4, 1 case](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=05608CK), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md)
- [Performance/control parameters: descent/approach/glide path](https://openairdocs.org/ntsb-findings/01062040): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Leeper Damon L RV-4, 1 case](https://openairdocs.org/ntsb-findings/01062040/cases.md?model=05608CK), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md)

## Sequence of events

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

- [Approach-VFR pattern final: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Leeper Damon L RV-4, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=05608CK), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md)
- [Approach-VFR pattern final: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Leeper Damon L RV-4, 1 case](https://openairdocs.org/ntsb-events/400/sequence.md?model=05608CK), [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md)

## Analysis

The pilot reported that, as he approached the airport, he noted there was turbulence, and that the windsock was indicating light winds. While on the short-final leg of the traffic pattern for runway 16, the airplane encountered a downdraft. The airplane’s sink rate increased and in response, the pilot applied full engine power. Despite his attempt to arrest the descent, the airplane touched down about 200 ft before the runway in soft terrain. The airplane nosed over coming to rest inverted. Both wings were substantially damaged.

## Aircraft

- Registration: [N345DL](https://openairdocs.org/deregistered/N345DL-2022-12-16), registration cancelled 2022-12-16, S/N 1345, built 1994 (OpenAirDocs)
- Reported make and model: VANS RV4
- Registry model: [Leeper Damon L RV-4](https://openairdocs.org/model/leeper-damon-l-rv-4) (registry code 05608CK) (OpenAirDocs)
- Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 1345
- Year built: 1994
- Airframe hours: 625
- Engines: Lycoming O-360 180 hp reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Special, Experimental (Special)
- Departed: KSEZ, Sedona, AZ
- Destination: Same as departure
- Airport: UT25, Monument Valley, runway 16/34, 4,000 × 75 ft, asphalt
- Equipment: ADS-B

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 56; injuries: minor; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: front; restraint: 4-point; flight hours: 475 total, 135 in this make and model, 413 as pilot in command, 15 in the last 90 days, 6 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 190° at 22 knots, gusting 32
- Visibility: 10 statute miles
- Temperature: 66 °F, dew point 14 °F
- Altimeter: 29.86 inHg
- Observed at: KBDG, 48 nm away
- METAR: KBDG 141935Z AUTO 19022G32KT 10SM 19/M10 A2986 RMK AO1 T01911096

## Docket (2 files)

The files NTSB released with the investigation on September 1, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102978. 9.5 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 7 pages, 9.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12276149&FileExtension=pdf&FileName=Z-%20Attachment%2001%20-6120_Redacted-Rel.pdf
- Photograph of airplane (provided by FAA) (item 2, PDF, 1 page, 246 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12276498&FileExtension=pdf&FileName=Z-%20Attachment%2002%20-Photos-Rel.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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