History of Flight
On May 3, 2011, at 1740 mountain daylight time, the pilot of a Piper PA46-500TP, registration N46ME, aborted the takeoff at Rock Springs-Sweetwater County Airport, Rock Springs, Wyoming, after the right main landing gear tire failed. The airline transport pilot operated the airplane under Title 14 Code of Federal Regulations, Part 91. Visual meteorological conditions prevailed, and an IFR flight plan had been filed.
The pilot reported that during the takeoff roll, as the airplane approached 70 knots, it started slowly pulling to the right. He immediately aborted the takeoff and stopped the airplane on the runway using brakes and reverse propeller thrust. Upon inspection, the pilot found the right main landing gear tire blown and the right aileron buckled at the aileron center hinge location. No scuff marks or indentations indicated that the hinge or surrounding area had been struck by debris. The hinge remained attached to the aileron, but the attach bracket connecting the hinge to the wing had fractured. The operator removed the entire hinge component and associated pieces, which were sent to the NTSB Materials Laboratory for examination.
Tests and Research
The NTSB Materials Laboratory examination revealed that the aileron hinge attach brackets were each fractured at three places, all located at manufactured bend locations. Optical examinations of the fracture faces showed deformation and fracture features consistent with overstress separations. Further observation with a scanning electron microscope uncovered ductile dimples on the fracture surfaces, indicating both shearing and tensile overstress forces. No indications of progressive separation or corrosion were found.
Photographs of the blown tire, a Goodyear Flight Special II (part number 606C81B1, serial number 8029718), were examined by a technical representative of Goodyear Aviation Tires. The representative assessed the tire as exhibiting a typical “run-flat” condition. The distorted shape, blue rubber, and liner appearance were consistent with a tire that had been run overdeflected (underinflated and/or overloaded) during service. The upper sidewall appeared to have been cut from the adjacent areas of the tire by running between the wheel flange and runway surface due to the overdeflected condition.
Additional Information
The airplane manufacturer reported knowledge of a similar incident on January 20, 2010, involving a different PA46, where a main tire blew and the aileron center hinge failed in a similar fashion. Piper Aircraft’s engineering department is currently investigating the hinge and the unusual phenomena associated with the failure.