# NTSB WPR23LA354: Kerr John Hatz Classic, N687HZ, Ennis, MT, April 29, 2023

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 4 · Limited · Final report
- Date: April 28, 2023, 18:00 local (Apr 29, 2023, 00:00 UTC)
- Place: Ennis, MT · KEKS
- Coordinates: 45.275725, -111.64891 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.2757&lon=-111.6489&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230)
- Highest injury: No injuries
- Injuries: 1 uninjured
- 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): 193150
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA354
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193150/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193150
- Page: https://openairdocs.org/ntsb/WPR23LA354

## Probable cause

The pilot’s failure to maintain directional control during the landing roll which resulted in a ground-loop.

## 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: [Kerr John HATZ CLASSIC, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=056278E), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/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: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Kerr John HATZ CLASSIC, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=056278E), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md)

## Analysis

The pilot of the tailwheel equipped, experimental amateur-built airplane, reported that during the landing roll he decreased the airplane’s speed to exit the runway, but a ground loop ensued. He did not recall whether he inadvertently applied the heel brakes, or if the airplane encountered a wind gust. The meteorological aerodrome report located at the accident airport about the time of the accident reported that, the wind was out of 130° and the wind velocity was 4 knots. The airplane sustained substantial damage to the bottom left wing spar. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

## Aircraft

- Registration: [N687HZ](https://openairdocs.org/aircraft/N687HZ), registered now, S/N 687, built 2009 (OpenAirDocs)
- Reported make and model: KERR JOHN HATZ CLASSIC
- Registry model: [Kerr John HATZ CLASSIC](https://openairdocs.org/model/kerr-john-hatz-classic) (registry code 056278E) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 687
- Year built: 2009
- Airframe hours: 116
- Engines: Rotec R3600 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Condition, April 15, 2023, 6 hours before
- Departed: U02, Blackfoot, ID
- Destination: EKS, Ennis, MT
- Flight plan: VFR
- Airport: EKS, Ennis Big Sky, runway 16, 7,600 × 100 ft, asphalt
- Equipment: Handheld GPS, Electronic flight bag or handheld device

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 73; injuries: none; commercial, private; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: basicmed, with waivers/limitations; last flight review September 28, 2023; seat: rear; restraint: 4-point; flight hours: 2,111 total, 6 in this make and model, 2,056 as pilot in command, 10 in the last 90 days, 3 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 130° at 4 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 64 °F, dew point 19 °F
- Altimeter: 30.22 inHg
- Observed at: KEKS, 1 nm away
- METAR: METAR KEKS 282355Z AUTO 13004KT 10SM CLR 18/M07 A3022 RMK AO2=

## 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 20230428018639A](https://openairdocs.org/incident/20230428018639A), Apr 28, 2023: Kerr John HATZ CLASSIC, Ennis, MT, Substantial damage. Description of the deviation: While operating a Hatz Classic experimental biplane on a VFR flight plan and upon landing on rwy 16 at the Ennis, MT airport…

## Docket (2 files)

The files NTSB released with the investigation on April 4, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193150. 2.5 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16514578&FileExtension=pdf&FileName=6120_1_Redacted-Rel.pdf
- Photographs (item 2, PDF, 2 pages, 451 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16515001&FileExtension=pdf&FileName=Photographs-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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