- Date
- July 26, 2025, 10:33 local (15:33 UTC)
- Place
- New Holstein, WI
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N83PSAerotek Pitts S-2A
- Defining event
- Landing-landing roll: Sys/Comp malf/fail (non-power)
- Weather
- Visual (VMC) · Day
- Status
- Completed · report October 30, 2025
- Report
- Approved by Office Director
- Investigation class
- Class 4 - Basic report with no Prelim publish
- NTSB office
- Central Region
- Parties
- FAA
- FAA report
- 20250726013969A
- Case key
- 200634
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The pilot’s loss of direction control during landing due to an unapproved tailwheel assembly and tail spring that resulted in a tailwheel shimmy and a subsequent ground loop.
Findings · 3
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
The pilot reported that during landing on the asphalt runway, with a passenger in the front seat, the airplane had a significant tailwheel shimmy. The pilot attempted to stop the shimmy by lifting the tailwheel off the runway as the airplane continued to decelerate. As the speed decreased, the tailwheel settled back onto the runway and shimmied again, but directional control was maintained. However, the shimmy eventually became more adverse, and the pilot was unable to maintain directional control of the airplane. The airplane ground looped to the left, came to rest adjacent to the runway, and sustained substantial damage to the right wing and empennage. Postaccident examination revealed that an unapproved tailwheel assembly and tail spring were installed. The tailwheel created a negative castor angle and reduced trail, which was exacerbated by the additional weight of the rear occupant, and resulted in the tailwheel shimmy during landing.
Aircraft
- Registration
- N83PS
- Reported as
- Aerotek Pitts S-2A
- Category
- Airplane
- Serial number
- 2143
- Built
- 1977
- Airframe hours
- 550.44
- Engine
- Lycoming AEIO-360-A1A, 180 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Airworthiness certificate
- Standard, Aerobatic
- Last inspection
- Annual · May 1, 2025
- Departed
- Kosh · Oshkosh, WI
- Destination
- 8D1 · New Holstein, WI
- Airport
- 8D1 · New Holstein Municipal Airport, runway 14/32, 3,600 × 75 ft, asphalt
- Equipment
- Stall warning system, ADS-B
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 50
- Injuries
- None
- Certificate
- Airline transport
- Airplane ratings
- Multi-engine land, Single-engine sea, Single-engine land
- Instrument ratings
- Airplane
- Medical
- Class 3, Without waivers/limitations
- Last flight review
- April 11, 2025
- Seat
- Rear
- Restraint
- 5-point
- Flight hours
- 3,308 total · 30.6 in this make and model · 3,165 as pilot in command · 42.8 in the last 90 days · 21.1 in the last 30 days · 0.5 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 77 °F, dew point 68 °F
- Altimeter
- 29.98 inHg
- Observed at
- KSBM, 15 nm away
- METAR
- KSBM 261453Z AUTO 00000KT 10SM CLR 25/20 A2998 RMK AO2 SLP149 T02500200 55002
Docket · 4
The files NTSB released with the investigation on November 4, 2025, on NTSB’s docket system: statements, records, photos and specialists’ reports. 2.6 MB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.