Sunday, April 14, 2019

Aerodynamic Stall: Piper PA-18A 150 Super Cub, N9496D, accident occurred June 21, 2018 at Llano Municipal Airport (KAQO), Texas

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; San Antonio, Texas

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


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


Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf

https://registry.faa.gov/N9496D

Location: Llano, TX
Accident Number: GAA18CA583
Date & Time: 06/21/2018, 1000 CDT
Registration: N9496D
Aircraft: Piper PA18
Aircraft Damage: Substantial
Defining Event: Aerodynamic stall/spin
Injuries: 2 None
Flight Conducted Under: Part 91: General Aviation - Instructional 

Analysis 

The pilot receiving instruction in the tailwheel-equipped airplane reported that, during landing, the airplane touched down abruptly. He added that he taxied to the edge of the runway and saw that the airplane was leaning left.

The flight instructor reported that the pilot leveled off about 3 ft above the ground and allowed the airspeed to decrease. He added that he instructed the pilot to add power to "cushion the landing" and that the pilot attempted to do so, but the airplane continued to decelerate until it aerodynamically stalled and landed hard on the left main landing gear.

The airplane sustained substantial damage to the fuselage.

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

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot's receiving instruction’s improper landing flare and his failure to maintain adequate airspeed and his exceedance of the airplane's critical angle of attack during landing, which resulted in an aerodynamic stall.

Findings

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

Personnel issues
Aircraft control - Student pilot (Cause)

Factual Information

History of Flight

Landing
Aerodynamic stall/spin (Defining event)
Hard landing

Flight Instructor Information

Certificate: Flight Instructor; Commercial
Age: 68, Male
Airplane Rating(s): Single-engine Land; Single-engine Sea
Seat Occupied: Rear
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): Airplane Single-engine; Instrument Airplane
Toxicology Performed: No
Medical Certification: Class 2 Waiver Time Limited Special
Last FAA Medical Exam: 04/04/2018
Occupational Pilot: Yes
Last Flight Review or Equivalent:
Flight Time:  (Estimated) 11456 hours (Total, all aircraft), 1252 hours (Total, this make and model), 11359 hours (Pilot In Command, all aircraft), 28 hours (Last 90 days, all aircraft), 5 hours (Last 30 days, all aircraft)

Pilot Information

Certificate: Flight Instructor; Commercial
Age: 41, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Unknown
Other Aircraft Rating(s): Helicopter
Restraint Used: Unknown
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): Airplane Multi-engine; Airplane Single-engine; Helicopter; Instrument Airplane
Toxicology Performed: No
Medical Certification: Class 1 Without Waivers/Limitations
Last FAA Medical Exam: 11/13/2018
Occupational Pilot: 
Last Flight Review or Equivalent:
Flight Time:  (Estimated) 1826 hours (Total, all aircraft), 1.3 hours (Total, this make and model)

Aircraft and Owner/Operator Information

Aircraft Make: Piper
Registration: N9496D
Model/Series: PA18
Aircraft Category: Airplane
Year of Manufacture: 1958
Amateur Built: No
Airworthiness Certificate: Normal; Utility
Serial Number: 18-6748
Landing Gear Type: Tailwheel
Seats: 2
Date/Type of Last Inspection: 12/29/2017, Annual
Certified Max Gross Wt.: 2000 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 5346.9 Hours as of last inspection
Engine Manufacturer: Lycoming
ELT: C126 installed, not activated
Engine Model/Series: O-320-A2B
Registered Owner: On file
Rated Power: 150 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: KAQO, 1102 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 1515 UTC
Direction from Accident Site: 252°
Lowest Cloud Condition: Few / 1000 ft agl
Visibility:  10 Miles
Lowest Ceiling:
Visibility (RVR):
Wind Speed/Gusts: Calm /
Turbulence Type Forecast/Actual: None / None
Wind Direction:
Turbulence Severity Forecast/Actual: N/A / N/A
Altimeter Setting: 30.01 inches Hg
Temperature/Dew Point: 26°C / 22°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Llano, TX (AQO)
Type of Flight Plan Filed: None
Destination: Llano, TX (AQO)
Type of Clearance: None
Departure Time: 0950 CDT
Type of Airspace: Class G

Airport Information

Airport: LLANO MUNI (AQO)
Runway Surface Type: Grass/turf
Airport Elevation: 1101 ft
Runway Surface Condition: Dry
Runway Used: 31
IFR Approach: None
Runway Length/Width: 3209 ft / 150 ft
VFR Approach/Landing: Full Stop

Wreckage and Impact Information

Crew Injuries: 2 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 None
Latitude, Longitude: 30.784167, -98.661389 (est)

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