Kolb TWINSTAR accident near Starbuck, Minnesota, June 2, 2023
On June 2, 2023 at about 7:50 pm local time, a 2021 Kolb TWINSTAR, an amateur-built aircraft,, registered N1025T, was substantially damaged in an accident during landing (flare/touchdown) near Starbuck, Minnesota (Starbuck Muni airport). It was an instructional flight under general aviation rules (Part 91). 1 person was seriously injured and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot’s improper landing flare and hard landing, which resulted in the left axle fracturing from bending overstress.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 2, 2023 · about 7:50 pm local time
- Place
- Starbuck, Minnesota · Starbuck Muni · map
- Type
- Accident
- Injuries
- 1 person was seriously injured and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Kolb TWINSTAR III, built 2021, amateur-built
- Registration
- N1025T · registry record · serial M3X20-4-00116
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The flight instructor and the pilot, who was also the builder of the airplane, were practicing soft field landings with the tailwheel-equipped experimental airplane. They performed two three-point landings to the dry turf without incident. During touchdown on the third landing, with the pilot on the flight controls, the left wheel departed from the left strut. The airplane began sliding on the turf and nosed over, coming to rest inverted. The airplane sustained substantial damage to the fuselage, both wings, and the empennage. A postaccident metallurgical examination of the left main landing gear revealed that it failed when the left axle fractured from bending overstress consistent with upward forces on the wheel and outward portion of the axle. It is likely that the pilot executed an improper landing flare, which resulted in a hard landing that fractured the left axle in bending overstress, and a subsequent loss of control and nose over.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Part(s) separation from AC during landing (flare/touchdown)
- Loss of control on ground during landing (flare/touchdown)
- Abnormal runway contact during landing (flare/touchdown) defining event
- Nose over/nose down during landing (flare/touchdown)
- Evacuation during post (impact)
The NTSB's findings
- Aircraft › Aircraft systems › Landing gear system › Main gear strut/axle/truck › Failure
- Aircraft › Aircraft systems › Landing gear system › Main gear strut/axle/truck › Capability exceeded
- Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Landing flare › Not attained/maintained
- Personnel issues › Action/decision › Action › Incorrect action performance › Pilot
Flight instructor
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 1,581 hours in all; 3 in this make and model; 245 in the last 90 days; 90 in the last 30 days; 1,534 as pilot in command; 1,174 on instruments
- Last flight review: February 5, 2022
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: rgt
- Injury: minor injuries
Pilot
- Certificate: private
- Ratings: single-engine land; single-engine sea
- Flight time: 250 hours in all; 8.9 in this make and model; 12 in the last 90 days; 6 in the last 30 days; 250 as pilot in command
- Last flight review: July 16, 2022
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 40 hours
- Last inspection: annual inspection, May 15, 2023; 2 hours since
- Maximum gross weight: 1,320 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rotax Aircraft Engines 912 ULS (piston); 40 hours total
The flight
- Departed from: AXN Alexandria MN at 7:09 pm
- Flight plan: none
- Runway 15/3, 2,512 ft by 198 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 190° at 8 knots, gusting 15
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 86°F (30°C), dew point 63°F (17°C)
- Altimeter: 30.02 inHg
- Observation at 2:55 pm from KGHW, 9 miles away
Weather report (METAR): KGHW 021955Z AUTO 19008G15KT 10SM CLR 30/17 A3002 RMK AO2
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
7 documents, released by the NTSB on July 10, 2024. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 (Flight Instructor) | PDF, 9 pages | View Download |
| 2 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 (Pilot/builder) | PDF, 7 pages | View Download |
| 3 | Accident Photographs | PDF, 3 pages | View Download |
| 4 | Pilot/builder - Additional Question (Brake System) | PDF, 2 pages | View Download |
| 5 | Pilot's Most Recent Flight Review | PDF, 1 page | View Download |
| 6 | Materials Laboratory Factual Report | PDF, 15 pages | View Download |
| 7 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 2 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.