WPR10LA479

The failure of a manufacturing splice of the right main landing gear tire’s inner tube, which resulted in a deflated tire and a consequent loss of directional control on landing.

According to the pilot, after a normal touchdown the airplane began a skidding turn to the right. The pilot was unable to keep the airplane on the runway and it struck a runway light during the runway excursion, which occurred as a result of a deflated tire on the right main landing gear. On-scene examination revealed that the valve of the tire's inner tube had separated from the tube. The left main landing gear tire was found to be properly inflated, the tread depth on both the left and right main landing gear tires was sufficient, and neither the left nor the right main landing gear tires exhibited any indications of abnormal wear. The pilot indicated that the right tire and tube were replaced about 17 months before the accident and that they had accumulated about 295 hours and 107 cycles in service. The tube was manufactured about 1 year prior to its installation. Examination of the tube and the recovered valve revealed that a small area of a manufacturing splice had opened, which permitted the tube to deflate. The deflated tire then slipped on the wheel during landing, which separated the valve from the tube body. The tube manufacturer did not provide any reasons for the splice failure. Neither the root cause nor the exact timing of the splice failure could be determined.

HISTORY OF FLIGHT On September 30, 2010, about 1555 Pacific daylight time, a Piper PA-46-350P, N90SE, was substantially damaged during a landing veer off at Felts Field (SFF), Spokane, Washington. Neither the commercial pilot/owner nor the four passengers were injured. The cross-country business flight was operated under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the business flight. The airplane departed Richland Airport (RLD), Richland, Washington, with SFF as the intended destination. Just after the airplane touched down in what the pilot described as a normal landing on runway 3L at SFF, the airplane began a skidding turn to the right. The pilot stated that he was unable to correct the turn. The airplane departed the right side of the runway, and the right main landing gear struck a runway light. The landing gear and right wing were damaged by the impact. PERSONNEL INFORMATION Federal Aviation Administration (FAA) records indicated that the pilot held a commercial certificate with airplane single-engine land, airplane multiengine land, and airplane instrument ratings, and a flight instructor certificate with airplane single-engine land and airplane multiengine land ratings. The pilot reported that he had 4,593 total hours of flight experience, including 1,240 in the accident airplane make and model. His most recent flight review was completed in August 2009. AIRCRAFT INFORMATION The airplane was manufactured in 1989, and registered to the accident pilot/owner in 2006. FAA airworthiness and registration documentation indicated that the airplane was equipped with a Lycoming IO-540 series reciprocating engine. However, information provided by Piper, the pilot/owner, and the FAA inspector indicated that the airplane was equipped with a PT-6A series turbine engine. The reason for the incorrect FAA airworthiness and registration information could not be determined. At the time of the accident, the airplane had accumulated a total time (TT) in service of about 1,742 hours. Its most recent inspection was completed in October 2009. METEOROLOGICAL INFORMATION The 1553 automated weather observation at SFF included calm winds; clear skies; temperature 27 degrees C; dew point 8 degrees C; and an altimeter setting of 29.95 inches of mercury. AIRPORT INFORMATION The FAA Airport/Facility Directory indicated that runway 3L was concrete, and measured 4,500 feet by 150 feet. WRECKAGE AND IMPACT INFORMATION The airplane came to rest about 1,400 feet beyond the landing threshold of the runway; the left wing tip was approximately even with the right edge of the runway. The FAA inspector who responded to the accident reported that the valve of the tire's inner tube had fracture-separated from the tube. The separated valve was recovered. Both the left and right main landing gear tires had tread depths within the allowable tolerances, and neither tire bore any indications of damage due to abnormal braking or skidding. The left (intact) main landing gear tire pressure was measured to be 53 pounds per square inch (psi), which was slightly less than the optimum pressure of 55 psi. According to the inspector's visual examination of the components, the wear and cracking patterns on the separated valve stem "indicated an earlier partial separation" of the valve. The inspector did not observe any indications of slippage of the right tire on the wheel. ADDITIONAL INFORMATION Inner Tube The failed inner tube was a Goodyear Tire brand "Butyl Aircraft Tube." Identifying characters ink-stamped onto the tube included: - "G15/6.00/-6" (tube size) - "MAR 08" (manufacture date) According to the pilot, the tire and tube were purchased and installed on the airplane in early April 2009. At the time of the accident, they had accumulated about 295 hours and 107 cycles in service, and about 137 hours since their most recent inspection. After the accident, the tube was removed from the airplane and shipped to Goodyear for examination. The Goodyear representative indicated that the tube was manufactured by Bridgestone. The tube was examined and then sent to Bridgestone for additional examination. According to a Goodyear letter that documented the joint findings, a "small area" of a manufacturing splice had "opened," which permitted the tube to deflate, and then allowed the tube to slip with respect to the wheel. The valve was subsequently "torn off." The letter also noted that the valve was equipped with a cap/extension that measured 1 3/4 inches long; the standard VC5 cap was 1/2 inch long. The Goodyear letter stated that it was "unknown if this cap is approved for aviation use." A representative of Piper Aircraft confirmed that the VC5 cap was standard for the airplane, but that Piper was aware of the extension caps being installed on their airplanes. The representative did not provide any possible adverse effects that could result from installation of the valve extension. A review of tire manufacturer's and FAA guidance regarding inner tubes indicated that inner tubes should never be reinstalled or reused. The cited reason for this was that inner tubes "grow" approximately 25 per cent in service, and take a permanent set. Reinstallation will result in folds, wrinkles or creases in the tube material, which then causes premature failure of the material. There was no evidence that the subject tube was reused, but its reuse could not be disproved, either.