CEN12LA300

The pilot realized that the right main landing gear failed to extend before landing; they followed the emergency checklist procedure to manually pump the gear down. However, the pilot was unable to extend the gear, and the right main landing gear collapsed upon landing. When the airplane was recovered, the right gear was locked in the extended position, and the airplane was towed to a hangar and placed on jacks. The landing gear was then cycled successfully numerous times; the right main landing gear's failure to extend could not be duplicated. Further examination revealed that the top end of the right main landing gear's downlock adjustment screw was slightly bent. When the bent screw was positioned so that it leaned against the landing gear's downlock mechanism during the extension cycle, the landing gear system's downlock engaged before the gear was fully seated in the gear saddle. The position of the adjustment downlock screw was not documented until after the landing gear had been cycled several times; however, the condition is consistent with the pilot’s inability to manually extend the landing gear using the emergency hand pump. No other mechanical anomalies were noted, and the landing gear system operated normally after the adjustment downlock screw was replaced. It is unknown how the downlock adjustment screw got bent or how long it had been in that condition.

On May 9, 2012, approximately 1030 central daylight time, N727FA, a Cessna T210K airplane, sustained substantial damage during an emergency landing at Midland International Airport (MAF), Midland, Texas. The commercial pilot and the passenger were not injured. The airplane was registered to and operated by Corporate Services LLC, Baton Rouge, Louisiana. An instrument flight rules (IFR) flight plan was filed for the flight that departed Baton Rouge Metropolitan Airport (BTR), Baton Rouge, Louisiana, approximately 0630. Visual meteorological conditions prevailed for the personal flight conducted under 14 Code of Federal Regulations Part 91. In a written statement, the pilot stated that the flight was uneventful until he configured the airplane for landing. When he extended the landing gear, the right main gear would not fully extend. As per the emergency checklist, the pilot attempted to manually pump the gear down with the emergency gear pump, but the gear would not extend. He declared an emergency and landed. During the landing roll, the right main landing gear collapsed and the airplane veered right off the runway. The airplane sustained substantial damage to the right horizontal stabilizer and elevator; however, airport personnel were able to pull the right main gear into the down-and-locked position and tow it to a hangar. According to a representative of the company that maintains the airplane, he said the airplane was placed on jacks and the gear was successfully swung several times. The anomaly that caused the right main landing gear to not fully extend could not be duplicated. Further examination revealed the top-end of the right main landing gear's downlock adjustment screw was slightly bent and loose. Though the actual position of the screw at the time of the accident was never noted, it was determined that if it was moved into a certain position, the screw would lean against the gear's down lock mechanism during the extension cycle. This caused the landing gear system's downlock to prematurely engage before the gear was fully seated in the gear saddle. A review of the airplane's emergency procedure for a landing gear extension failure revealed the pilot was instructed to use the emergency hand pump to manually extend the gear. However, based on the unique circumstances of the bent downlock adjustment screw, use of the emergency hand pump would not have been effective in extending the gear. The maintenance facility found no other mechanical anomalies with the landing gear system and replaced the bent downlock adjustment screw. The gear was then swung numerous times without incident and the airplane was returned to service. It was unknown how the right downlock adjustment screw got bent or how long it had been in that condition prior to the accident.