NTSB Factual Report

On September 23, 2017, about 1415 Pacific daylight time, a Yak-52W, N52KF, sustained substantial damage following a reported loss of control while taxiing at Gillespie Field Airport (SEE), El Cajon, California. The airplane was registered to an individual and operated by the pilot under the provision of Title 14 Code of Federal Regulations Part 91. The pilot and the passenger were not injured. Visual meteorological conditions prevailed and no flight plan has been filed.

The pilot reported that he conducted a normal preflight, completed the starting engine checklist and attempted to start the engine, but was unable to do so due to a required recharge of the pneumatic system. Another individual arrived with a tank of air to pressurize the system, which allowed the pilot to remain in the airplane. The pilot had shut off the compressed air supply valve, as required in the first step in recharging the pneumatic system, to ensure against over pressurizing the system. The individual with the tank of air realized that they had accidentally brought the wrong adapter for the subject airplane and left to find the correct adapter. A second individual arrived and offered to assist to start the engine by manually turning the propeller, while the pilot primed the cylinders as there appeared to be sufficient existing air pressure. Subsequently, the engine started.

The pilot completed the post start checklist and started to taxi. Shortly thereafter, the pilot experienced a loss of braking performance which affected the airplane's steering capabilities. The pilot realized that the compressed air supply valve was shut off and attempted to turn it back on while turning the engine off and maintaining steering control. Due to the size constraints of the cockpit, the pilot could not reach the supply valve without unstrapping and turning around before the airplane impacted the fence.