Incident Details
On March 14, 2011, at approximately 1150 eastern daylight time, a Cessna 414, registered as N40NY to FJS Assets LLC, experienced a collapse of the right main landing gear during the landing roll at Long Island MacArthur Airport (ISP), New York. Visual meteorological conditions prevailed, and no flight plan was filed for the 14 CFR Part 91 personal flight. The airline transport pilot and a pilot-rated passenger were not injured. The flight originated from Bridgeport, Connecticut, and landed uneventfully on runway 06. The pilot then requested and received clearance for a touch-and-go landing to check engine parameters with warm engines. After remaining in the traffic pattern for runway 06, the pilot extended the landing gear and confirmed three green lights indicating down and locked. The airplane landed normally at about 100 knots, touching down at or near the intersection of runway 06 and taxiway A1. During the landing roll, after applying brakes and traveling about 200 to 300 feet at 70 to 75 knots, the pilot began applying right rudder to turn onto runway 10 and then taxiway Sierra. During the turn, the right main landing gear slowly collapsed, causing the right wing to contact the runway. The airplane departed the runway and collided with a runway marker sign.
Post-Accident Examination
Postaccident examination by Federal Aviation Administration (FAA) inspectors revealed that one lug of the right main landing gear trunnion assembly was fractured at the bellcrank assembly attach point. The attach bolt (P/N NAS464P4-26) securing the bellcrank to the trunnion assembly was also fractured. The head of the bolt remained trapped inside the unbroken lug of the trunnion, while the lower portion with the castellated nut and cotter pin remained inside the bellcrank. Additionally, one retainer of the nose landing gear was pulled from its structural attach point. The right main landing gear cylinder, trunnion assembly, bellcrank, and fractured bolt were retained for further examination.
The National Transportation Safety Board’s Materials Laboratory examined the right cylinder and trunnion assembly and the fractured bolt. The Materials Laboratory Factual Report indicated that the fracture surface of the aft lug of the trunnion was matte-gray with a rough texture, consistent with ductile overstress fracture. The bolt was fractured in the shank area where it intersected the forward lug of the trunnion. The fracture surfaces had a uniform smooth appearance with deformation consistent with ductile overstress fracture under shear loading. Further examination showed the shank diameter measured 0.245 inch, while the specified minimum is 0.2483 inch. Hardness testing averaged 37.0 HRC; the minimum specified is 36.0 HRC.
Maintenance History
During an annual inspection completed on March 1, 2011, discrepancies were found with the right upper strut assembly. The upper strut assembly was removed and sent to an FAA-certified repair station (CRS), where it was inspected and rendered unserviceable. A replacement upper strut assembly was located and sent to the same CRS for inspection. Records indicate the replacement was bead blasted, inspected, painted, and approved for return to service. The inspected upper strut assembly was installed during the annual inspection, and the airplane was returned to service. The airplane total time at the annual inspection was 7,320.6 hours; approximately 2 hours had accrued since the replacement upper strut assembly was installed.
The airplane service manual notes that following procedures for rigging the main and nose landing gears results in a properly rigged system. An engineering specialist from Cessna Aircraft Company reported that proper rigging of the landing gear in the down and locked position results in the upper and lower side links of the main landing gear being over-center. Without the side links being over-center, the load path from the main landing gear is transmitted to the trunnion lugs.