- Date
- September 21, 2020, 14:05 local (22:05 UTC)
- Place
- King Salmon, AK
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N182KTCessna 182
- Defining event
- Landing-landing roll: Sys/Comp malf/fail (non-power)
- Weather
- Visual (VMC) · Day
- Status
- Completed
- Report
- Approved by Office Director
- Investigation class
- Class 3
- NTSB office
- Alaska Regional Office
- Parties
- FAA
- FAA report
- 20200921018569A
- Case key
- 102032
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 fatigue fracture failure of the left main landing gear U-bolt during landing, which resulted in the collapse and separation of the left main landing gear spring.
Findings · 1
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.
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
The pilot reported that, after a normal touchdown in crosswind conditions, the left main landing gear (MLG) began to shake and rattle. The shaking continued and became more severe as the airplane continued its landing roll, and the airplane subsequently began to veer to the left and exited the runway. As the airplane came to rest, the MLG spring separated from the fuselage, resulting in substantial damage to the left horizontal stabilizer and elevator. A postaccident examination of the left MLG spring attach hardware fractured surfaces revealed that the left MLG U-bolt failed due to fatigue cracking and the MLG support bolt fractured within the shank due to shear loads.
Factual narrative
On September 21, 2020, about 1405 Alaska daylight time, a Cessna 182C airplane, N182KT, sustained substantial damage when it was involved in an accident near King Salmon, Alaska. The private pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, after a normal touchdown in crosswind conditions, the left main landing gear (MLG) began to shake and rattle. The shaking continued and became more severe as the airplane continued the landing roll, and the airplane subsequently began to veer to the left and exited the runway. As the airplane came to rest, the left MLG spring separated from the fuselage, resulting in substantial damage to the left horizontal stabilizer and elevator. An initial examination of the airplane by the pilot revealed that the left MLG spring U-bolt and MLG support bolt fractured, allowing the left MLG spring to separate from the fuselage. A visual and microscopic examination of the left MLG spring attach hardware revealed a fatigue crack in the U-bolt that emanated in the first thread root of the U-bolt and propagated substantially through the thickness of the thread until it reached a critical size and ultimately failed due to overstress. Examination of the MLG bolt revealed that the bolt fractured within the shank due to shear loads.
Aircraft
- Registration
- N182KT
- Reported as
- Cessna 182 (C)
- Category
- Airplane
- Serial number
- 52854
- Built
- 1960
- Airframe hours
- 6,693
- Engine
- Continental O-470 SERIES, 230 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · December 5, 2019
- Departed
- King Salmon, AK
- Destination
- Same as departure
- Airport
- PAKN · King Salmon, runway 12, 8,901 × 150 ft, asphalt
- Equipment
- Unknown
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 32
- Injuries
- None
- Certificate
- Private
- Airplane ratings
- Single-engine land
- Medical
- Class 3, Without waivers/limitations
- Last flight review
- October 25, 2018
- Seat
- Left
- Restraint
- 3-point
- Flight hours
- 391.4 total · 327.1 in this make and model · 328.3 as pilot in command · 117.2 in the last 90 days · 45.5 in the last 30 days · 2.6 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 80° at 15 knots, gusting 25
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 57 °F, dew point 39 °F
- Altimeter
- 29.27 inHg
- Observed at
- PAKN, 1 nm away
Docket · 4
The files NTSB released with the investigation on January 14, 2022, on NTSB’s docket system: statements, records, photos and specialists’ reports. 68.9 MB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.