Sunday, July 07, 2019

System / Component Malfunction / Failure (Non-Power): Beech 1900C, N172GA, accident occurred April 29, 2018 at Joe Foss Field Airport (KFSD), Sioux Falls, South Dakota

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Salt Lake City, Utah

Aviation Accident Final Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board: 

Aviation Accident Data Summary - National Transportation Safety Board:

Location: Sioux Falls, SD
Accident Number: CEN18LA164
Date & Time: 04/29/2018, 2230 CDT
Registration: N172GA
Aircraft: BEECH 1900C
Aircraft Damage: Substantial
Defining Event: Sys/Comp malf/fail (non-power)
Injuries: 1 None
Flight Conducted Under: Part 135: Air Taxi & Commuter - Non-scheduled


As the twin-engine, turbopropeller-equipped airplane started to taxi for takeoff, the right main landing gear collapsed, deforming the aft center wing lower spar cap. A postaccident examination of the airplane revealed that the right main landing gear drag brace bolt failed at the wing forward attach point. As the airplane moved forward, the strut pivoted aft, collapsing the landing gear. The drag brace bolt was not retained, and the reason for its failure could not be determined based on the available information.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
Failure of the right main landing gear drag brace bolt for reasons that could not be determined based on the available information. 


Main landing gear attach sec - Failure (Cause)
Spar (on wing) - Fatigue/wear/corrosion

Factual Information

On April 29, 2018, about 2230 central daylight time, a Beech 1900C, N172GA, was substantially damaged when the right main landing gear collapsed as the airplane started to taxi for takeoff at Joe Foss Field Airport (FSD), Sioux Falls, South Dakota. The airline transport pilot was not injured. The airplane was registered to and operated by Alpine Aviation, doing business as Alpine Air Express, under the provisions of Title 14 Code of Federal Regulations Part 135 as a non-scheduled domestic cargo flight. Visual meteorological conditions prevailed at the airport at the time of the accident, and an instrument flight rules flight plan had been filed. The flight was originating from FSD, and was destined for Rapid City Regional Airport (RAP), Rapid City, South Dakota.

According to Federal Aviation Administration (FAA) inspectors, the airplane had just moved forward to taxi for takeoff when the right main landing gear collapsed. A postaccident examination of the airplane revealed the right main landing gear drag brace bolt failed at the wing forward attach point. The drag brace bolt was not retained for further examination. The strut pivoted aft when the airplane moved forward, and the landing gear collapsed. The aft center wing lower spar cap was dented and deformed up to 0.090". Further examination found pitting corrosion on the spar cap. 

History of Flight

Sys/Comp malf/fail (non-power) (Defining event)
Landing gear collapse 

Pilot Information

Certificate: Airline Transport; Flight Instructor; Commercial
Age: 57, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used:  
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): Airplane Multi-engine; Airplane Single-engine; Instrument Airplane
Toxicology Performed: No
Medical Certification: Class 2 With Waivers/Limitations
Last FAA Medical Exam: 10/13/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent: 11/28/2017
Flight Time:  13968 hours (Total, all aircraft), 1000 hours (Total, this make and model), 8000 hours (Pilot In Command, all aircraft), 133 hours (Last 90 days, all aircraft), 50 hours (Last 30 days, all aircraft), 3 hours (Last 24 hours, all aircraft) 

Aircraft and Owner/Operator Information

Aircraft Make: BEECH
Registration: N172GA
Model/Series: 1900C
Aircraft Category: Airplane
Year of Manufacture: 1982
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: UB-11
Landing Gear Type: Retractable - Tricycle
Seats: 2
Date/Type of Last Inspection: 03/10/2018, AAIP
Certified Max Gross Wt.: 16600 lbs
Time Since Last Inspection: 117 Hours
Engines: 2 Turbo Prop
Airframe Total Time: 41851 Hours at time of accident
Engine Manufacturer: Pratt & Whitney
ELT: C91  installed, not activated
Engine Model/Series: PT6A-65B
Registered Owner: Alpine Aviation, Inc.
Rated Power: 1100 hp
Operator: Alpine Aviation, Inc.
Operating Certificate(s) Held: On-demand Air Taxi (135)
Operator Does Business As: Alpine Air Express
Operator Designator Code: TIMA 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Night
Observation Facility, Elevation: KFSD, 1429 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 2256 CDT
Direction from Accident Site: 0°
Lowest Cloud Condition:
Visibility:  10 Miles
Lowest Ceiling: Broken / 10000 ft agl
Visibility (RVR):
Wind Speed/Gusts: 15 knots /
Turbulence Type Forecast/Actual:
Wind Direction: 160°
Turbulence Severity Forecast/Actual:
Altimeter Setting: 29.8 inches Hg
Temperature/Dew Point: 20°C / 7°C
Precipitation and Obscuration:
Departure Point: Sioux Falls, SD (FSD)
Type of Flight Plan Filed: IFR
Destination: Rapid City, SD (RAP)
Type of Clearance: None
Departure Time: 2230 CDT
Type of Airspace: Class D

Airport Information

Airport: Joe Foss Field (FSD)
Runway Surface Type: N/A
Airport Elevation: 1429 ft
Runway Surface Condition:
Runway Used: N/A
IFR Approach: None
Runway Length/Width:
VFR Approach/Landing: None 

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 43.581944, -96.741944 (est)

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