Primary finding
Probable cause
The fatigue failure of the right main landing gear hydraulic actuator, which resulted in a loss of hydraulic fluid that prevented the pilot from lowering the landing gear to the fully extended position.
Investigator assessment
Analysis narrative
The pilot reported that during landing gear retraction after takeoff, he heard a “pop” from the rear cockpit area, and the landing gear retraction handle did not return to the center position as expected. He attempted to extend the landing gear, but they would not extend. He performed the emergency extension procedures; the landing gear doors opened, and the landing gear came out of their respective landing gear wells. However, only the nose landing gear locked into the down position, and the main landing gear remained partially extended. During the landing, the airplane skidded to a stop and incurred substantial damage to the left horizontal stabilizer and elevator. Postaccident examination of the airplane found the right hydraulic actuator had a fatigue crack that initiated along the retaining ring groove of the actuator that rendered the actuator inoperable and resulted in a loss of hydraulic fluid from the system. Due to the loss of fluid, neither the primary system nor the emergency system could lower and lock all the landing gear in place for landing.
Source record
Factual narrative
On October 18, 2023, about 1736 mountain daylight time, a Cessna 210B airplane, N9597X, was substantially damaged when it was involved in an accident near Pueblo, Colorado. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that during landing gear retraction after takeoff, he heard a “pop” from the rear cockpit area, and the landing gear retraction handle did not return to the center position as expected. He attempted to extend the landing gear, but they would not extend. He performed the emergency extension procedures; the landing gear doors opened, and the landing gear came out of their respective landing gear wells. However, only the nose landing gear locked into the down position, and the main landing gear remained partially extended. The pilot contacted the Pueblo Municipal Airport (PUB), Pueblo, Colorado, airport traffic control tower and chose to remain airborne for several hours to burn off fuel. The pilot made multiple additional attempts to lower the landing gear. These were unsuccessful, and the pilot eventually landed on runway 8R at PUB. During the landing, the nose landing gear remained in the down position and the main landing gear were in a partially extended position. The airplane skidded to a stop and incurred substantial damage to the left horizontal stabilizer and elevator. Postaccident examination of the airplane revealed that the right hydraulic actuator was fractured. The actuator was further examined by the NTSB Materials Laboratory. This examination revealed features consistent with fatigue cracking initiating along the retaining ring groove of the actuator, the remainder of the cross-section fracturing from mixed overstress and fatigue once the fatigue crack grew to its terminal size, and the housing barrel then fracturing in overstress.