# NTSB DEN88LA094: Agusta A109A, N33SV, Sioux Falls, SD, April 9, 1988

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: April 9, 1988, 12:15 local (17:15 UTC)
- Place: Sioux Falls, SD
- Location: 43.5820° N, 96.7419° W: Placed by OpenAirDocs at JOE FOSS FLD (FSD), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=43.5820&lon=-96.7419&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report February 28, 1989
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 17463
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN88LA094
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/17463/pdf
- Page: https://openairdocs.org/ntsb/DEN88LA094

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach - vfr pattern - final approach
  - rotor drive system,tail rotor drive shaft bearing - disintegrated (cause)
  - rotor drive system,tail rotor drive shaft - sheared (cause)
  - maintenance,lubrication - not performed, company maintenance personnel (cause)
- Loss of control - in flight, landing - flare/touchdown
  - directional control - not possible
- Main gear collapsed, landing - flare/touchdown
  - landing gear,main gear attachment - overload

## Aircraft

- Registration: N33SV (not matched to a registry record)
- Reported make and model: AGUSTA A109A
- Category: Helicopter
- Serial number: 7154
- Airframe hours: 2303
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Positioning, Part 91
- Operator: Rocky Mountain Helicopters
- Registered owner: Icon Group Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, July 20, 1987, 5 hours before
- Departed: 1SD9, SIOUX FALLS, SD
- Airport: FSD, Joe Foss Field

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 44; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 1, valid medical--no waivers/lim.; seat: right; flight hours: 13,615 total, 120 in this make and model, 13,150 as pilot in command, 50 in the last 90 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 350° at 23 knots, gusting 35
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 46 °F, dew point 25 °F
- Altimeter: 30.00 inHg
- Observed at: FSD

## 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 19880409012419A](https://openairdocs.org/incident/19880409012419A), Apr 9, 1988: Agusta A109, Sioux Falls, SD, Substantial damage. Landing for refueling loud snap and loss of tail rotor caused crash landing. Drive shaft broke on bearing siezure.

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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