Sunday, July 26, 2020

Hard Landing: Piper PA-18-150 Super Cub, N82912; accident occurred August 18, 2017 at Avenger Field Airport (KSWW), Sweetwater, Nolan County, Texas

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

Additional Participating Entities:

Federal Aviation Administration / Flight Standards District Office; Lubbock, Texas
United States Department of Agriculture (USDA) / Animal and Plant Health Inspection Service (APHIS) / Wildlife Services; Cedar City, Utah

Aviation Accident Factual Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board: 

Location: Sweetwater, TX
Accident Number:CEN17LA324 
Date & Time: 08/18/2017, 1145 CDT
Registration: N82912
Aircraft: PIPER PA 18-150
Aircraft Damage: Substantial
Defining Event: Hard landing
Injuries: 2 None
Flight Conducted Under: Public Aircraft

On August 18, 2017, about 1145 central daylight time, a Piper PA-18-150 airplane, N82912, was substantially damaged while landing at Avenger Field Airport (SWW), Sweetwater, Texas. The commercial pilot and his passenger were not injured. The airplane was registered to and operated by the United States Department of Agriculture (USDA) as a public aircraft.

The pilot reported that he chose to land on runway 17 at SWW because the automated weather observing system at the airport indicated the surface wind was 9 knots from the south-southwest. The pilot stated that he intended to make a wheel landing with the flaps fully extended. He stated that he felt a "little bump" shortly after the airplane touched down on the right main landing gear (MLG), and the airplane began to swerve left. The pilot reported that he was unable to regain directional control with full right rudder and right brake inputs. The airplane continued to swerve left and departed the left runway edge where the right MLG collapsed after it entered soft terrain. The airplane came to rest on a north heading. The airplane sustained substantial damage to the right wing, both main wing spars, and the right elevator.

The Federal Aviation Administration inspector who examined the wreckage identified several fractured MLG components, which were subsequently submitted to the National Transportation Safety Board Materials Laboratory for additional examination.

The left-side MLG hydrasorb shock unit was intact with its external shock cord rings wrapped around its tee flanges. The left MLG brace tube was bent and fractured near where it attached to the left hydrasorb shock unit. Adjacent to the fracture surface, the brace tube exhibited local thinning or necking. The tube fracture surface exhibited either a cup-shaped morphology, or a flat orientation angled at about 45° relative to the tube direction. The observed fracture features and tube damage were consistent with tensile overstress. There was no evidence of preexisting cracks or damage to the left MLG brace tube or its associated hydrasorb shock unit.

The right-side MLG brace tube had buckled and was partially fractured about 5.75 inches from the fitting hole. The fracture surface exhibited a general rough texture with a dull luster, which was consistent with tensile overstress. Additionally, the opposite end of the right MLG brace tube had buckled inward toward the partial fracture. The observed brace tube damage was consistent with bending overstress.

The right-side MLG hydrasorb shock unit exhibited a fracture of its internal piston shaft. The piston shaft had bent downward adjacent to the fracture surface. One side of the fracture exhibited a generally flat surface on one half before it transitioned to a 45° shear lip. Additional examination of the fracture with a scanning electron microscope revealed dimple rupture in a slanted orientation. The observed fracture features and damage to the internal piston shaft were consistent with bending overstress. There was no evidence of preexisting cracks or damage to the internal piston shaft. The chemical composition, microstructure, and measured material hardness were consistent with a martensitic precipitation-hardened stainless-steel alloy.

Pilot Information

Age: 57, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Front
Other Aircraft Rating(s): None
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 2 With Waivers/Limitations
Last FAA Medical Exam: 08/07/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent: 04/04/2017
Flight Time:  10245 hours (Total, all aircraft), 10163 hours (Total, this make and model), 10070 hours (Pilot In Command, all aircraft), 58 hours (Last 90 days, all aircraft), 36 hours (Last 30 days, all aircraft), 3 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: PIPER
Registration: N82912
Model/Series: PA 18-150
Aircraft Category: Airplane
Year of Manufacture: 1977
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 18-7709195
Landing Gear Type: Tailwheel
Date/Type of Last Inspection: 07/05/2017, Annual
Certified Max Gross Wt.: 2000 lbs
Time Since Last Inspection: 46 Hours
Engines: 1 Reciprocating
Airframe Total Time: 10623.9 Hours at time of accident
Engine Manufacturer: Lycoming
ELT: C126 installed, not activated
Engine Model/Series: O-360-C4P
Registered Owner: USDA-APHIS-WS
Rated Power: 180 hp
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: SWW, 2380 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 1135 CDT
Direction from Accident Site:
Lowest Cloud Condition:
Visibility:  10 Miles
Lowest Ceiling: Broken / 8000 ft agl
Visibility (RVR):
Wind Speed/Gusts: 6 knots /
Turbulence Type Forecast/Actual: / None
Wind Direction: 230°
Turbulence Severity Forecast/Actual: / N/A
Altimeter Setting: 30.16 inches Hg
Temperature/Dew Point: 29°C / 20°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Winston Field, TX (SNK)
Type of Flight Plan Filed: Company VFR
Destination: Sweetwater, TX (SWW)
Type of Clearance: None
Departure Time: 1120 CDT
Type of Airspace: Class G

Airport Information

Airport: Avenger Field Airport (SWW)
Runway Surface Type: Asphalt
Airport Elevation: 2380 ft
Runway Surface Condition: Dry
Runway Used: 17
IFR Approach: None
Runway Length/Width: 5840 ft / 100 ft
VFR Approach/Landing: Traffic Pattern

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: 1 None
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries:2 None
Latitude, Longitude: 32.471667, -100.469167

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