Beech E-55 N855T accident near Wichita Falls, Texas

Probable cause

The failure of the landing gear assembly snap ring, which prevented the pilot from being able to extend the landing gear and resulted in a gear-up landing. Also causal was the lack of the assembly's overhaul in accordance with the airplane maintenance manual.

NTSB analysis

The flight instructor stated that, after the landing gear handle was placed in the gear-down position, he and the student pilot noticed electrical smoke and fumes but no fire. Although they restored electrical power, they were unable to fully extend the landing gear, which resulted in a gear-up landing.

Postaccident examination of the main landing gear retraction actuator assembly revealed a broken snap ring within the manual crank extension housing, which allowed the actuator worm gear to reposition itself beyond the actuator worm sector travel limits. A review of the airplane's maintenance records found no record showing that the landing gear actuator assembly had been repaired/overhauled in accordance with the airplane maintenance manual. According to the maintenance manual, the actuator assembly is to be overhauled or replaced every 2,000 hours for gray- or green-colored assemblies. The assembly that was examined was green. The airplane had a total time of 6,184.5 hours. Given the condition of the landing gear actuator assembly, the operator should have been overhauled or replaced the actuator assembly in accordance with the manual.

Text from the NTSB. Open the NTSB docket for CEN16LA336 for the full record.