Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office; Sacramento, California
Textron Aviation; Wichita, Kansas
Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms
http://registry.faa.gov/N71RC
Location: Jackson, CA
Accident Number: WPR17LA051
Date & Time: 01/06/2017, 1720 PST
Registration: N71RC
Aircraft: CESSNA 421C
Aircraft Damage: Substantial
Defining Event: Landing gear collapse
Injuries: 1 None
Flight Conducted Under: Part 91: General Aviation - Personal
On January 6, 2017, about 1720 Pacific standard time, a Cessna 421C airplane, N71RC, sustained substantial damage to the right wing spar following the collapse of the right main landing gear during the landing roll at Westover Field/Amador County Airport, Jackson, California. The airline transport rated pilot was not injured. The airplane was registered to and operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed, and no flight plan was filed for the cross country flight. The flight originated from the Palo Alto Airport, Palo Alto, California about 1640.
The pilot stated that he flew a normal left-hand traffic pattern for runway 19. The flare and initial touchdown were normal, however, immediately after the initial touchdown, something did not feel right. When he attempted to lightly apply the brakes the airplane began to yaw from one side to the other. He released the brakes and attempted to slow the airplane with reverse thrust, but the airplane exited the paved runway surface and came to a stop in the grass and dirt area about 20 ft off the right side of the runway. During the landing the right main landing gear collapsed.
An onsite examination of the airplane revealed that the right main landing gear torque link assembly had separated at the hinge attach point due to the failure of the torque link bolt. The bolt's nut, cotter pin and washer were not located during the investigation.
The subject bolt was subsequently shipped to the National Transportation Safety Board's Materials Laboratory in Washington, D.C. for examination. As a result of the examination, the report revealed that the torque link bolt threads had been rounded over and exhibited remnants of material consistent with the threads of the mating nut. Further, remains of a cotter pin that was installed through the bolt hole were also visible. The report concluded that the deformation of the cotter pin remains was indicative of a shear overstress fracture. (Refer to the NTSB Materials Laboratory Factual Report No. 18-062, which is appended to the docket for this report.)
It was revealed during the investigation that Federal Aviation Administration (FAA) Special Airworthiness Information Bulletin (SAIB) CE-14-19, dated May 30, 2014, titled "Landing Gear; Main Landing Gear (MLG) Torque Link," was published to advise owners, operators, and maintenance technicians of Cessna 300 and 400 Models and Series of an airworthiness concerns, specifically the need to inspect the MLG torque link assembly to ensure the correct thickness washers are installed, and to ensure the washers are installed properly. The SAIB was preceded by Cessna Service Bulletin ME83-37, dated November 23, 1983, "Main Landing Gear Scissor Washer Replacement which recommended replacement of the two outer washers on the main landing gear scissor link for Cessna Model 421s, and Cessna Service Bulletin MEB02-12, which specified replacement of the original washers at each end of hinge point attachment stack-up for Cessna Model 310s. (Refer to FAA SAIB CE-14-9, and Cessna Service Bulletin ME83-37, both of which are appended to the docket for this report.)
Except for the right main landing gear torque link bolt, no other components of the right main landing gear assembly were accounted for during the investigation. Additionally, no maintenance records were recovered during the investigation for review to determine compliance with the SAIB's.
The pilot did not submit a Pilot/Operator Aircraft Accident/Incident Report (NTSB) Form 6120.1.
Pilot Information
Certificate: Airline Transport
Age: 58, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Left
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: 12/11/2015
Occupational Pilot:No
Last Flight Review or Equivalent:09/04/2016
Flight Time: 1802 hours (Total, all aircraft), 62 hours (Total, this make and model)
Aircraft and Owner/Operator Information
Aircraft Make: CESSNA
Registration: N71RC
Model/Series:421C C
Aircraft Category: Airplane
Year of Manufacture: 1977
Amateur Built:No
Airworthiness Certificate: Normal
Serial Number: 421C0423
Landing Gear Type: Retractable - Tricycle
Seats:
Date/Type of Last Inspection: 08/11/2016, AAIP
Certified Max Gross Wt.: 7500 lbs
Time Since Last Inspection: 11 Hours
Engines: 2 Turbo Prop
Airframe Total Time: 2929.1 Hours as of last inspection
Engine Manufacturer: Lycoming
ELT: Installed
Engine Model/Series: LTP 101-600
Registered Owner: On file
Rated Power: 600 hp
Operator: On file
Operating Certificate(s) Held: None
Meteorological Information and Flight Plan
Conditions at Accident Site: Visual Conditions
Condition of Light: Dusk
Observation Facility, Elevation: KSMF, 23 ft msl
Distance from Accident Site: 42 Nautical Miles
Observation Time: 0053 UTC
Direction from Accident Site: 297°
Lowest Cloud Condition: Scattered / 15000 ft agl
Visibility: 10 Miles
Lowest Ceiling: Broken / 25000 ft agl
Visibility (RVR):
Wind Speed/Gusts: 4 knots /
Turbulence Type Forecast/Actual: None / None
Wind Direction: 10°
Turbulence Severity Forecast/Actual: N/A / N/A
Altimeter Setting:30.1 inches Hg
Temperature/Dew Point: 4°C / 2°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Palo Alto, CA (PAO)
Type of Flight Plan Filed: Unknown
Destination: Jackson, CA (JAQ)
Type of Clearance: None
Departure Time: 1640 PST
Type of Airspace:Class G
Airport Information
Airport: WESTOVER FIELD AMADOR COUNTY (JAQ)
Runway Surface Type: Asphalt
Airport Elevation: 1694 ft
Runway Surface Condition:Dry
Runway Used: 19
IFR Approach: None
Runway Length/Width: 3401 ft / 60 ft
VFR Approach/Landing: Traffic Pattern
Wreckage and Impact Information
Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries:N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 38.376944, -120.794167 (est)
NTSB Identification: WPR17LA051
14 CFR Part 91: General Aviation
Accident occurred Friday, January 06, 2017 in Jackson, CA
Aircraft: CESSNA 421C, registration: N71RC
Injuries: 1 Uninjured.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
On January 6, 2017, about 1720 Pacific standard time, a twin-engine, turbine powered, Cessna 421C, N71RC, sustained substantial damage following the collapse of the right main landing gear during the landing roll at Westover Field/Amador County Airport, Jackson, California. The flight was being conducted as a personal cross country flight under the provisions of 14 Code of Federal Regulations Part 91 when the accident occurred. The airline transport rated pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed and no flight plan was on file. The flight originated from the Palo Alto Airport, Palo Alto, California about 1640.
The pilot stated that he flew a normal left traffic pattern for runway 19. The flare and initial touchdown were normal, however immediately after the initial touchdown, something did not feel right. He attempted to lightly apply the brakes, and the airplane began to yaw from one side to the other. He released the brakes and attempted to slow the airplane with reverse thrust but the airplane exited the paved runway surface and came to a stop in the grass and dirt area about 20 feet off the right side of the runway.
Initial examination of the airplane revealed that the right main landing gear torque link separated at the hinge attach point. Further examination of the torque link assembly is pending recovery of the airplane.
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