Accident Details
On February 1, 2017, at approximately 1715 central standard time, an experimental S C Aerostar S A Yak-52, registration N624PT, was substantially damaged during an emergency landing at St. Elmo Airport (2R5), St. Elmo, Alabama. The private pilot, who was the sole occupant, was not injured. The flight was operated under 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The local flight originated from 2R5 about 1700.
Sequence of Events
The pilot reported that the landing gear system was pneumatic. Shortly after takeoff and retracting the landing gear, he observed low pneumatic pressure. He attempted to extend the landing gear using both normal and emergency procedures, but the right main landing gear remained retracted. The pilot then performed an emergency landing with the right main landing gear retracted. During the landing roll, he kept the right wing from contacting the runway for approximately 1,000 feet. Once the wing contacted the runway, directional control was lost, and the airplane came to rest upright in a grass area off the right side of the runway.
Aircraft Information
The airplane was manufactured in the former Soviet Union in 1985, imported to the United States in 2003, and issued an FAA experimental airworthiness certificate. Some maintenance records were not imported, so total airframe time could not be determined. The most recent annual condition inspection was completed on October 1, 2016. At that time, the engine had accumulated about 504 hours since overhaul. The airplane operated for 18 hours from that inspection until the accident.
Examination Findings
Examination by a Federal Aviation Administration (FAA) inspector revealed substantial damage to the right aileron. Additionally, the inspector and a local mechanic noted that the pneumatic cylinder actuator (P/N 524705-30) for releasing the right main landing gear uplock was not functioning properly. A subsequent teardown examination of the actuator showed that moisture had entered and corroded internal components. The mechanic stated plans to install a dryer system on the compressor to prevent moisture accumulation in the pneumatic lines and to disassemble and inspect landing gear actuators every two to three years for corrosion. An organization of owners of the same make and model airplane was alerted regarding the actuator issue.