Pilot Debrief

KOLB TWINSTAR near Starbuck, MN — 2023-06-02

Final reportCEN23LA227
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Date
2023-06-02
Location
Starbuck, MN, USA
Airport
D32
Aircraft
KOLB TWINSTAR
Registration
N1025T
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Landing

Probable cause

The pilot’s improper landing flare and hard landing, which resulted in the left axle fracturing from bending overstress.

NTSB narrative

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.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have adjusted landing technique to prevent gear failure.

NTSB coding

Evidence available

  • Photos
  • 7 docket documents
View NTSB final reportView NTSB docket

Docket documents7

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