ERA22LA296

NTSB accident investigation · American Champion 8KCAB · Knoxville, TN · June 28, 2022

Accident · No injuriesClass 4 · LimitedFinal report
Date
June 28, 2022, 10:30 local (14:30 UTC)
Place
Knoxville, TN
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N721SDAmerican Champion 8KCAB
Defining event
Landing: Sys/Comp malf/fail (non-power)
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 4 - Basic report with no Prelim publish
NTSB office
Eastern Region Aviation
Parties
FAA-FSDO
Case key
105404

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

The inadequate maintenance of the left main landing gear through bolt, which resulted in a left main landing gear collapse and subsequent runway excursion during landing.

Findings · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Landing gear system: main landing gear attach secAircraft › Aircraft systems · FailureAll aircraft: 66 casesProbable cause
Maintenance: scheduled/routine maintenancePersonnel issues › Task performance · Maintenance personnelAll aircraft: 320 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

After performing maneuvers in the local area, the pilot receiving instruction and the flight instructor returned to the departure airport and performed two practice landings. During the third landing, the flight instructor heard a “bang” noise and the airplane veered left away from the runway centerline. The airplane came to rest in the grass next to the runway and the airplane’s fuselage and rudder were substantially damaged. A Federal Aviation Administration inspector examined the airplane after the accident. The airplane’s left main landing gear had collapsed and the inspector found that the left main landing gear through bolt was fractured. The inspector further reported that the airplane’s most recent annual inspection had been completed more than 22 months before the accident. Additionally, the airframe manufacturer’s maintenance manual required that the through bolt be removed and inspected at every 100 hour/annual inspection and replaced as necessary, in addition to a mandatory replacement every 500 hours. The airplane’s maintenance records did not show when the last though bolt change had occurred. Based on this information, it is likely that the landing gear collapsed due to a failure of the left main landing gear through bolt, and that the through bolt had likely not been maintained in accordance with the airframe manufacturer’s requirements.

Aircraft

Registration
N721SD
Reported as
American Champion 8KCAB
Category
Airplane
Serial number
722-93
Built
1993
Airframe hours
2,318
Engine
Lycoming IO-360, 180 horsepower, reciprocating
Damage
Substantial damage
Flight
Instructional · Part 91
Operator
Super D Aviation Training Co LLC
Registered owner
Super D Aviation Training Co LLC
Airworthiness certificate
Standard, Aerobatic; Standard, Normal
Last inspection
Annual · August 1, 2020 · 170 hours before
Airport
DKX · Knoxville Downtown Island, runway 8, 3,499 × 75 ft, asphalt
Equipment
Stall warning system, ADS-B

Flight crew · 2

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
20
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 2, Without waivers/limitations
Last flight review
August 19, 2021
Seat
Front
Flight hours
63.1 total · 2.7 in this make and model · 16.8 as pilot in command · 5.9 in the last 90 days · 2.7 in the last 30 days
Role
Flight instructor
Age
73
Injuries
None
Certificates
Military, Commercial, Airline transport, Flight instructor, Flight engineer
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 3, With waivers/limitations
Last flight review
February 2, 2022
Seat
Rear
Restraint
3-point
Flight hours
25,000 total · 1,000 in this make and model · 20,000 as pilot in command · 200 in the last 90 days · 80 in the last 30 days · 3 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Visibility
10 statute miles
Lowest ceiling
None
Temperature
75 °F, dew point 59 °F
Altimeter
30.21 inHg
Observed at
DKX
METAR
METAR KDKX 281415Z AUTO VRB04KT 10SM CLR 24/15 A3021 RMK A01

Docket · 5

The files NTSB released with the investigation on June 23, 2023, on NTSB’s docket system: statements, records, photos and specialists’ reports. 8.6 MB in all.