# NTSB CHI99LA335: Benson Sorrell SNS-7, N60SV, Mt. Vernon, IL, August 29, 1999

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 29, 1999, 11:45 local (16:45 UTC)
- Place: Mt. Vernon, IL
- Coordinates: 38.31076, -88.910278 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.3108&lon=-88.9103&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report June 21, 2000
- Report: Approved by Office Director
- NTSB case key (mKey): 47354
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI99LA335
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/47354/pdf
- Page: https://openairdocs.org/ntsb/CHI99LA335

## Probable cause

the pilot's inadequate compensation for the wind condition which resulted in an inadvertent ground loop.  A factor associated with the accident was the gusty crosswind.

## Sequence of events

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

- Loss of control - on ground/water, landing - roll
  - weather condition - crosswind (contributing factor)
  - weather condition - gusts (contributing factor)
  - compensation for wind conditions - inadequate, pilot in command (cause)
  - ground loop/swerve - inadvertent, pilot in command
- Main gear collapsed, landing - roll
  - landing gear,main gear - overload

## Analysis

The pilot reported that while landing on runway 23 a quartering crosswind from the left lifted the tail of the airplane to the right.  The airplane rotated 360 degrees and the right main landing gear collapsed.  The pilot reported local winds at the time of the accident were from 150 degrees at 15 knots gusting to 18 knots.

## Factual narrative

On August 29, 1999, at 1145 central daylight time (cdt), a Benson Sorrell SNS-7, N60SV, was substantially damaged when the airplane ground looped during a landing roll on runway 23 (6,498' x 150') at the Mt. Vernon Airport, Mt. Vernon, Illinois.  The pilot and passenger were not injured.  Visual meteorological conditions prevailed and no flight plan was filed.  The personal flight was operating under the provisions of 14 CFR Part 91.  The flight originated from Creve Couer, Missouri, at 1015 cdt.

The pilot reported that during the landing, "Upon rollout a quartering crosswind from port side lifted tail to starboard continuing 360 degrees causing the starboard landing gear to fold under the fuselage."

The pilot reported the local winds at the time of the accident were from 150 degrees at 15 knots gusting to 18 knots.

## Aircraft

- Registration: [N60SV](https://openairdocs.org/deregistered/N60SV-2018-05-30), registration cancelled 2018-05-30, S/N 236 (OpenAirDocs)
- Reported make and model: BENSON SORRELL SNS-7 (SORRELL SN)
- Registry model: [Benson Ronald C SORRELL SNS-7](https://openairdocs.org/model/benson-ronald-c-sorrell-sns-7) (registry code 05605VF) (OpenAirDocs)
- Registry engine: [Lycoming I0-360-B1E](https://openairdocs.org/engine/lycoming-i0-360-b1e) (registry code 41559, reciprocating) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 236
- Airframe hours: 381
- Engines: Lycoming IO-360-B1E 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Vernon A. Walser
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, March 29, 1999, 18 hours before
- Departed: 1H0, CREVE COUER, MO
- Destination: MVN
- Airport: MVN, Mt. Vernon, runway 23, 6,498 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 60; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 1,452 total, 100 in this make and model, 36 in the last 90 days, 18 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 150° at 15 knots, gusting 18
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 81 °F, dew point 57 °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 19990829030599A](https://openairdocs.org/incident/19990829030599A), Aug 29, 1999: Amtr SNS7, Mt Vernon, IL, Substantial damage. (.19) On August 29, 1999, at 1145 central daylight time (CDT), a benson sorrell SNS-7, N60SV, was substantially damaged when the airplane ground looped during…

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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