Thursday, August 31, 2017

Cessna 172G, N2982U, Belle Fourche Aero LLC: Accident occurred August 30, 2017 at Belle Fourche Municipal Airport (KEFC), Butte County, South Dakota

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

Location: Belle Fourche, SD
Accident Number: GAA17CA513
Date & Time: 08/30/2017, 1100 MDT
Registration: N2982U
Aircraft: CESSNA 172
Aircraft Damage: Substantial
Defining Event: Loss of control in flight
Injuries: 2 Minor
Flight Conducted Under: Part 91: General Aviation - Instructional

Analysis

The flight instructor reported that he was demonstrating a "full [aerodynamic] stall" landing for the student pilot in "stiff" gusting crosswind conditions. He added that the airplane crossed the runway threshold at 2 ft, the stall warning sounded, and then a "strong [wind] gust lifted the aircraft to…[approximately] 6 feet with the stall warning still sounding." He further added that he immediately applied power to go around, but the "gust died out." Subsequently, the left wing dropped and impacted terrain, and the airplane nosed over.

The fuselage, right wing, and vertical stabilizer sustained substantial damage.

The flight instructor reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

An automated weather observation station 17 nautical miles southwest from the accident site reported, about the time of the accident, wind from 110° at 12 knots. The landing was on runway 36.

The flight instructor failed to submit the National Transportation Safety Board Form 6120.1 Pilot/ Operator Aircraft Accident/ Incident Report.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The flight instructor's failure to maintain adequate airspeed and his exceedance of the airplane's critical angle of attack during a go-around in gusting crosswind conditions, which resulted in an aerodynamic stall.

Findings

Aircraft
Angle of attack - Capability exceeded (Cause)
Airspeed - Not attained/maintained (Cause)

Personnel issues
Aircraft control - Instructor/check pilot (Cause)

Environmental issues
Gusts - Effect on operation
Crosswind - Effect on operation
Factual Information

History of Flight

Landing-flare/touchdown
Other weather encounter
Approach-VFR go-around
Aerodynamic stall/spin
Loss of control in flight (Defining event)
Collision with terr/obj (non-CFIT)
Landing-flare/touchdown
Nose over/nose down

Flight Instructor Information

Certificate: Flight Instructor; Commercial
Age: 68, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Right
Other Aircraft Rating(s): None
Restraint Used: Unknown
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): Airplane Single-engine; Instrument Airplane
Toxicology Performed: No
Medical Certification: Class 2 With Waivers/Limitations
Last FAA Medical Exam: 06/26/2017
Occupational Pilot: 
Last Flight Review or Equivalent: 
Flight Time: 

Student Pilot Information

Certificate: None
Age: Male
Airplane Rating(s): None
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used: Unknown
Instrument Rating(s): None
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: None None
Last FAA Medical Exam: 
Occupational Pilot: No
Last Flight Review or Equivalent: 
Flight Time:

Aircraft and Owner/Operator Information

Aircraft Manufacturer: CESSNA
Registration: N2982U
Model/Series: 172 G
Aircraft Category: Airplane
Year of Manufacture: 1966
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 17254808
Landing Gear Type: Tricycle
Seats: 4
Date/Type of Last Inspection:  Unknown
Certified Max Gross Wt.: 2300 lbs
Time Since Last Inspection: 
Engines: 1 Reciprocating
Airframe Total Time:
Engine Manufacturer: CONT MOTOR
ELT: 
Engine Model/Series: O-300 SER
Registered Owner: BELLE FOURCHE AERO LLC.
Rated Power: 145 hp
Operator: On file
Operating Certificate(s) Held:  None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KSPF, 3933 ft msl
Observation Time: 1615 UTC
Distance from Accident Site: 17 Nautical Miles
Direction from Accident Site: 240°
Lowest Cloud Condition: Clear
Temperature/Dew Point: 25°C / 13°C
Lowest Ceiling: None
Visibility:  10 Miles
Wind Speed/Gusts, Direction: 12 knots, 110°
Visibility (RVR): 
Altimeter Setting: 30.16 inches Hg
Visibility (RVV): 
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: BELLE FOURCHE, SD (EFC)
Type of Flight Plan Filed: None
Destination: BELLE FOURCHE, SD (EFC)
Type of Clearance: None
Departure Time: 1030 MDT
Type of Airspace: Class G

Airport Information

Airport: BELLE FOURCHE MUNI (EFC)
Runway Surface Type: Grass/turf
Airport Elevation: 3190 ft
Runway Surface Condition: Dry
Runway Used: 36
IFR Approach: None
Runway Length/Width: 3634 ft / 125 ft
VFR Approach/Landing: Go Around; Touch and Go; Traffic Pattern

Wreckage and Impact Information

Crew Injuries: 2 Minor
Aircraft Damage:Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 Minor
Latitude, Longitude:  44.734444, -103.861944 (est)

Preventing Similar Accidents 

Prevent Aerodynamic Stalls at Low Altitude

While maneuvering an airplane at low altitude in visual meteorological conditions, many pilots fail to avoid conditions that lead to an aerodynamic stall, recognize the warning signs of a stall onset, and apply appropriate recovery techniques. Many stall accidents result when a pilot is momentarily distracted from the primary task of flying, such as while maneuvering in the airport traffic pattern, during an emergency, or when fixating on ground objects.

An aerodynamic stall can happen at any airspeed, at any altitude, and with any engine power setting. Pilots need to be honest with themselves about their knowledge of stalls and preparedness to recognize and handle a stall situation. Training can help pilots fully understand the stall phenomenon, including angle-of-attack (AOA) concepts and how weight, center of gravity, turbulence, maneuvering loads, and other factors can affect an airplane's stall characteristics. The stall characteristics may be different in each type of airplane, so learn them before you fly.

The stall airspeeds marked on the airspeed indicator (for example, the bottom of the green arc and the bottom of the white arc) typically represent steady flight speeds at 1G at the airplane's maximum gross weight in the specified configuration. Maneuvering loads and other factors can increase the airspeed at which the airplane will stall. For example, increasing bank angle can increase stall speed exponentially.

Reducing AOA by lowering the airplane's nose at the first indication of a stall is the most important immediate response for stall avoidance and stall recovery. This may seem counterintuitive at low altitudes, but is a necessary first step.

See http://www.ntsb.gov/safety/safety-alerts/documents/SA_019.pdf for additional resources.

The NTSB presents this information to prevent recurrence of similar accidents. Note that this should not be considered guidance from the regulator, nor does this supersede existing FAA Regulations (FARs).

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Rapid City, South Dakota

Aviation Accident Factual Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

Investigation Docket  - National Transportation Safety Board: https://dms.ntsb.gov/pubdms

Belle Fourche Aero LLC: http://registry.faa.gov/N2982U

NTSB Identification: GAA17CA513
14 CFR Part 91: General Aviation
Accident occurred Wednesday, August 30, 2017 in Belle Fourche, SD
Aircraft: CESSNA 172, registration: N2982U
Injuries: 2 Minor.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

The flight instructor reported that, he was demonstrating a "full [aerodynamic] stall" landing for the student pilot in "stiff" gusting crosswind conditions. He added that, the airplane crossed the runway threshold at two feet, the stall warning sounded, and then a "strong [wind] gust lifted the aircraft to appx [approximately] 6 feet with the stall warning still sounding." He further added that, he immediately applied power to go-around, but the "gust died out." Subsequently, the left wing dropped, impacted terrain, and the airplane nosed over.

The fuselage, right wing, and vertical stabilizer sustained substantial damage. 

The flight instructor did not report that there were any preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

An automated weather observation station, about the time of the accident, 17 nautical miles southwest from the accident site, reported wind from 110° at 12 knots. The landing was on runway 36.

The flight instructor failed to submit the NTSB Form 6120.1 Pilot/ Operator Aircraft Accident/ Incident Report.

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