ERA11LA011

During a routine agricultural application flight, the pilot noted that the right rudder pedal felt soft. He returned to the airport at the conclusion of the flight and, just after touchdown, applied pressure to both brake pedals to stop the airplane; while the left brake operated normally, the right brake was ineffective. The airplane subsequently departed the runway and was substantially damaged. A postaccident examination revealed evidence of brake fluid leakage at the internal fuselage hydraulic line fitting. No reliable determination of the brake fluid quantity prior to the accident could be made as the right brake system had been compromised during the accident, but testing of the system with replacement fluid lines showed normal operation.

HISTORY OF FLIGHT On October 1, 2010, about 1630 eastern daylight time, a Grumman G-164B, N48417, was substantially damaged following a runway excursion during landing at a private airfield in Edison, Georgia. The certificated commercial pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local aerial application flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 137. The pilot departed the private, turf runway on a routine application flight. He stated that during the flight, as he applied rudder pedal during turns, he felt that the right pedal was "soft," but stated that the left rudder pedal felt normal. He returned to the airport at the conclusion of the flight and just after touchdown, applied pressure to both brake pedals to stop the airplane. The pilot stated that the right pedal depressed to the floor and was ineffective, but the left pedal and left brake operated normally. The pilot applied reverse engine thrust, but the airplane continued left and departed the runway, where it came to rest upright. The airplane was examined at the accident site by a Federal Aviation Administration (FAA) inspector. The right main landing gear separated from the airplane, and both left and right upper and lower wings sustained substantial damage. PERSONNEL INFORMATION The pilot held a commercial pilot certificate with ratings for airplane single and multi engine land, instrument airplane, and rotorcraft helicopter. He reported 7,700 total hours of flight experience, approximately 4,000 hours of which were in the accident airplane make and model. His most recent flight review was completed in June, 2009. His most recent FAA second-class medical certificate was issued in March 2010 with no limitations. AIRCRAFT INFORMATION According to FAA records, the airplane was manufactured in 1976 and was powered by a Walter M601E-11 turbine engine, which was equipped with a three-bladed, Hamilton Standard propeller. The pilot stated that approximately one year prior to the accident, the airplane experienced a right brake failure during landing, but he was able to maintain control and the airplane sustained no damage. Subsequent inspection of the right brake master cylinder revealed a worn o-ring, which was replaced. The airplane's most recent annual inspection was completed on April 9, 2010, at which time the airplane had accumulated a total of 12,500 hours. The airplane's maintenance logs revealed that both left and right landing gear brake pads and all wheel bearings were replaced as part of the inspection. METEOROLOGICAL INFORMATION The 1639 weather observation at BIJ, located approximately 13 nautical miles southwest of the accident location, included winds from 320 degrees at 3 knots, 10 statute miles visibility, a scattered cloud layer at 7,500 feet, temperature 28 degrees C, dew point 12 degrees C, and an altimeter setting of 29.79 inches of mercury. ADDITIONALINFORMATION The airplane was recovered from the accident scene, and the right brake system was examined in detail by an FAA inspector. The inspector found evidence of brake fluid leakage at the internal fuselage hydraulic line fitting, but no evidence of leakage was observed at any other point in the system. The right brake line was separated during the accident sequence, and no fluid remained in the upper portion of the system or in the right brake caliper. As such, no reliable measure of the brake fluid quantity could be made as the right brake system had been compromised during the accident. A test line was fabricated, and the system was pressure-tested. Application of pressure at the brake master cylinder produced movement of the caliper, with a corresponding retraction of the caliper when pressure was removed.