# NTSB WPR10CA431: Hemmer MINI-MAX 1600R, N71031, Davis, CA, August 8, 2010

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: August 8, 2010, 11:00 local (18:00 UTC)
- Place: Davis, CA
- Coordinates: 38.574165, -121.854164 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.5742&lon=-121.8542&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 March 16, 2011
- Report: Approved by Office Director
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 77102
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10CA431
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/77102/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=77102
- Page: https://openairdocs.org/ntsb/WPR10CA431

## Probable cause

The airplane’s encounter with the wake turbulence of another aircraft.

## 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: [Hemmer MINI-MAX 1600R, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=05902U8), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md)
- [Turbulence: wake turbulence](https://openairdocs.org/ntsb-findings/03032025): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Hemmer MINI-MAX 1600R, 1 case](https://openairdocs.org/ntsb-findings/03032025/cases.md?model=05902U8), [All aircraft, 47 cases](https://openairdocs.org/ntsb-findings/03032025/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: [Hemmer MINI-MAX 1600R, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=05902U8), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md)

## Analysis

The pilot reported that while flying on the downwind leg of the traffic pattern in a single seat, tailwheel-equipped ultralight type airplane, he observed a Cessna airplane take off from the runway. When the Cessna was clear of the runway, the pilot conducted an uneventful wheel landing. During the landing roll, as the airplane approached the area where the Cessna lifted off, the airplane lifted off of the runway surface. The pilot applied full power but the airplane touched down hard, substantially damaging the wings and fuselage. The pilot reported no preimpact mechanical failures or malfunctions with the airframe or engine.

## Factual narrative

The pilot reported that while flying on the downwind leg of the traffic pattern in a single seat, tailwheel-equipped ultralight type airplane, he observed a Cessna airplane takeoff from the runway. When the Cessna was clear of the runway the pilot conducted an uneventful wheel landing. During the landing roll, as the airplane approached the area where the Cessna lifted off, the airplane was “picked up” from the runway. The pilot applied full power but the airplane was “slammed down hard,” substantially damaging the wings and fuselage. The pilot reported no mechanical failures or malfunctions with the airframe or engine prior to the accident.

## Aircraft

- Registration: [N71031](https://openairdocs.org/deregistered/N71031-2020-10-31), registration cancelled 2020-10-31, S/N JH001, built 2007 (OpenAirDocs)
- Reported make and model: HEMMER MINI-MAX 1600R
- Registry model: [Hemmer MINI-MAX 1600R](https://openairdocs.org/model/hemmer-mini-max-1600r) (registry code 05902U8) (OpenAirDocs)
- Registry engine: [Rotax 447](https://openairdocs.org/engine/rotax-447) (registry code 55576, 2 cycle) (OpenAirDocs)
- Category: Airplane
- Serial number: JH001
- Airframe hours: 139
- Engines: ROTAX 447 40 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Hemmer Joseph L
- Registered owner: Hemmer Joseph L
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Condition, November 6, 2009, 2 hours before
- Departed: KDWA, Davis, CA
- Destination: KDWA, Davis, CA
- Airport: KDWA, Yolo County Airport, runway 16, 6,000 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 73; injuries: none; private; airplane ratings: single-engine land; last flight review October 3, 2009; seat: single; flight hours: 80 total, 6 in this make and model, 80 as pilot in command, 7 in the last 90 days, 1 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 190° at 4 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 72 °F, dew point 57 °F
- Altimeter: 29.85 inHg
- Observed at: KEDU, 5 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).

- [Incident 20100808042319I](https://openairdocs.org/incident/20100808042319I), Aug 8, 2010: Hemmer MINI-MAX 16, Davis, CA, Substantial damage. On landing aircraft became airborne again and then landed hard on the second touch down. The landing was hard enought to collapse the main landing gear on both…

## Docket (1 files)

The files NTSB released with the investigation on October 6, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=77102. 522 KB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 522 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40336415&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-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.

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