20100521005679A

On may 21, 2010, N3633C, a Schweizer G-164B agcat was being flown during an agricultural seeding operation near Robbins, CA. During the flight, the pilot noticed that the right brake pedal was stiff. He looked down at the pedal area and noticed what appeared to be hydraulic fluid on his foot. There appeared to be a hydraulic leak coming from the parking brake valve located above his foot. The pilot tried to set and release the brake without success. He radioed in to his base of operations and notified ground personnel of the possible brake problems. He then completed the seeding application. The pilot attempted to land the aircraft to the south at Wagner field, (CA18) in Robbins, CA. The winds were estimated to be a direct cross wind 15G20 coming from the west. The landing attempt was made on the dirt strip adjacent to the asphalt runway. As soon as the aircraft touched down on the right wheel, the pilot felt the aircraft start to pull to the right. He corrected the aircraft's direction to the left. At this point, he felt that a wind gust shifted the aircraft to the left side of the asphalt runway and the aircraft went into an adjacent irrigation ditch. The left wing came to rest on the sloping terrain forming the ditch. The pilot and single occupant of the aircraft sustained an injury to his back in that he suffered a fracture to his vertebrae at L2. He was released from the hospital after a short stay. The aircraft sustained substantial damage to both the right and left wing spars. The propeller was substantially damaged and a large quantity of soil entered the engine intake. The left and right main landing gear struts were damaged when the aircraft went into the ditch. The right brake calipers were separated from the aircraft at the point of touchdown. The calipers were found within a few feet of the initial touchdown point of the right main landing gear tire. The aircraft was moved from the ditch to the company's hangar near the runway. The right wheel was found to have the entire inboard flange separated from the inboard wheel half. The tire was a tube type and the tube was still inflated. The tire expanded beyond where the flange once was and pushed the broken wheel flange pieces into the brake disc assembly. The tire was deflated and the parts were retained for examination. The attach points of the brake disc were found to be bulged and stressed. The attach points of the disc are located on the wheel assembly inner diameter. It appears that the force of the inflated tire and tube pushed inward radially against the brake disc with great force. It appears that wheel flange failed in-flight and gave the pilot a locked brake pedal feel. The pilot was properly certificated holding a commercial pilot's certificate. He had a current second class medical certificate dated 10/6/2009. His flight review was current and was last accomplished on 5/1/2009. The aircraft's inspection status was current. The last annual inspection was completed on 5/1/2010. The aircraft had no maintenance history concerning wheels and brakes. There was no evidence that the wheel and brake assembly were installed incorrectly. The failed wheel flange does not come in contact with the brake calipers or brake disc during normal operation. It appears that the wheel flange sustained a failure and allowed the inflated tire and tube to expand into the brake disc and brake caliper. A service difficulty report (SDR) was submitted to the FAA SDR database (SDR report # 2010FA0000510).