Cessna A185F N1848R accident near Skwentna, Alaska

Probable cause

Installation of improper hardware on the ski check cable. Contributing to the accident was the inadequate inspection of the ski yokes, which resulted in the subsequent failure of the right main landing gear ski yoke and collapse of the right main landing gear during the precautionary landing.

NTSB analysis

After takeoff from the remote frozen snow-covered lake, with the hydraulic-wheel-ski-equipped airplane, the unapproved retainer clip that the pilot had installed holding the right rear ski check cable disconnected for undetermined reasons. Subsequently, the right rear check cable “came loose” from the fuselage attach fitting and the right ski rotated to a nose-high position. The pilot was able to maintain control of the airplane; however, a “very serious” vibration was noted in the right horizontal stabilizer, and he chose to return to the departure lake to make a precautionary landing.

The pilot landed on untracked snow and as the ski was coming down “into its normal landing position,” the airplane veered hard to the right. The right main landing gear separated from the fuselage and the right wing impacted the snow. The fuselage sustained substantial damage.

There was a service bulletin (SB) published for the inspection and replacement of the ski yoke. The pilot reported that both he and his mechanic were unaware of the SB and that it had not been complied with. Compliance with information in the SB was not mandated by the Federal Aviation Administration.

The weld applied to the yoke joints failed due to lack of penetration of the weld metal into the base metal of the joints. The failure was a known issue and thus the accident could have been prevented by either continuous inspections of the welds, installation of the finger strap repair, or replacement of the yoke.

Text from the NTSB. Open the NTSB docket for ANC21LA022 for the full record.