# NTSB CHI06CA221: Air Tractor AT-400, N23720, Springfield, MN, July 31, 2006

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: July 31, 2006, 13:45 local (18:45 UTC)
- Place: Springfield, MN
- Coordinates: 44.214443, -94.999168
- Nearby events: https://openairdocs.org/map.md?lat=44.2144&lon=-94.9992&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report November 29, 2006
- Report: Approved by Office Director
- Parties: Minneapolis, MN FSDO
- NTSB case key (mKey): 64436
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI06CA221
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/64436/pdf
- Page: https://openairdocs.org/ntsb/CHI06CA221

## Probable cause

The pilot's inability to maintain directional control of the airplane as a result of the partial failure of the tail wheel assembly.  A factor associated with the accident was the crop that the airplane contacted.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, landing - roll
  - landing gear,tailwheel assembly - failure,partial (cause)
- Loss of control - on ground/water, landing - roll
  - directional control - not possible, pilot in command (cause)
- On ground/water encounter with terrain/water, landing - roll
  - terrain condition - crop (contributing factor)

## Analysis

The airplane ground looped following a failure of one of the tail wheel bolts.  The pilot reported that he was landing at a private grass airstrip when the accident occurred.  He reported that upon landing the tail wheel broke and the airplane ground looped.  Inspection of the airplane revealed that it traveled into a bean field during the ground loop and that the bottom bolt on the tail wheel assembly fractured which resulted in a loss of directional control.

## Factual narrative

The airplane ground looped following a failure of one of the tail wheel bolts.  The pilot reported he was landing at a private grass airstrip when the accident occurred.  He reported that upon landing the tail wheel broke and the airplane ground looped.  Inspection of the airplane by a Federal Aviation Administration Inspector from the Minneapolis, Minnesota Flight Standards District Office revealed the airplane traveled into a bean field during the ground loop.  The inspector reported the bottom bolt on the tail wheel assembly fractured which resulted in the loss of directional control.

## Aircraft

- Registration: [N23720](https://openairdocs.org/deregistered/N23720-2018-01-16), registration cancelled 2018-01-16, S/N 400-0422, built 1981 (OpenAirDocs)
- Reported make and model: Air Tractor AT-400
- Registry model: [Air Tractor AT-400](https://openairdocs.org/model/air-tractor-at-400) (registry code 0390202) (OpenAirDocs)
- Registry engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52034, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 400-0422
- Engines: Pratt & Whitney PT6A turbo prop
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Dlux Spray Service
- Registered owner: South Plains Aero, Inc
- Airworthiness certificate: Special, Restricted (Special)
- Departed: 27D, Canby, MN
- Destination: PVT, Springfield, MN

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2; flight hours: 1,750 total, 1,750 in this make and model, 50 in the last 90 days, 50 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 12 knots, gusting 20
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 91 °F

## 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 20060731017019A](https://openairdocs.org/incident/20060731017019A), Jul 31, 2006: Airtrc AT400, Springfield, MN, Substantial damage. (-23) Aircraft was landing on a Private airstip 7 miles n of Springfield, MN. As the aircraft touched down the pilot believes the tail wheel assembly failed…

## Other investigations on N23720 (1)

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.

- [NTSB CEN11LA593](https://openairdocs.org/ntsb/CEN11LA593), Aug 23, 2011: Air Tractor AT-400 (N23720), Monango, ND, substantial damage. Probable cause: The pilot did not maintain adequate separation from a tree during the aerial-application flight.

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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