FTW00LA121

The pilot reported that upon touchdown, the airplane 'felt like it had a flat tire and started pulling hard right.' Subsequently, the airplane exited the runway surface, the landing gear collapsed, and the airplane came to a stop upright. Examination of the landing gear revealed that the inboard half of the right main landing gear wheel had fractured through approximately 120 degrees of the flange. The fracture surface was examined at the NTSB Materials Laboratory in Washington, D.C., and exhibited striations, crack arrest positions, and ratchet marks, all of which are typical of fatigue propagation. The origin of the fatigue could not be determined as a result of rubber deposits on the fracture surface.

On April 9, 2000, at 1800 central daylight time a Piper PA-34-200T multi-engine airplane, N1571X, was substantially damaged when the landing gear collapsed during the landing roll at Drake Field, Fayetteville, Arkansas. The airline transport pilot, who was the registered owner and operator of the airplane, and his four passengers were not injured. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 91 personal flight, for which no flight plan was filed. The cross-country flight originated from the Golden Triangle Regional Airport, Columbus, Mississippi, at 1630, and was destined for Fayetteville, Arkansas.

According to the pilot, upon touchdown on runway 34, the airplane "felt like it had a flat tire and started pulling hard right." Subsequently, the airplane exited the runway surface, the landing gear collapsed, and the airplane came to rest 50 feet east of the runway.

The FAA inspector reported that the left main landing gear drag brace was fractured and the downlock assembly was displaced and had punctured the upper wing skin. The inboard side of the right main landing gear trunnion was collapsed and separated from the airframe. Approximately 1/3 of the flange of the wheel half assembly (inner) had fractured and was not recovered from the accident site. The fracture surface extended into the tube well area of the wheel assembly.

The right main landing gear and wheel assembly was examined at the NTSB Materials Laboratory in Washington D.C., by an NTSB Metallurgist and the Investigator-In-Charge. The tire did not exhibit flat spots or punctures. The tire tube was extracted and was observed to be torn. The wheel cap and wheel half assembly (outer) were removed and were intact. The brake disc assembly was removed and was intact. The wheel half assembly (inner) was removed and exhibited a fracture surface along the flange. The fracture surface extended through approximately 120 degrees of the flange and contained dark material deposits, of which the texture was consistent with rubber. The fracture surface exhibited striations, crack arrest positions, and ratchet marks on differing planes, all of which are typical of fatigue propagation. The origin of the fatigue could not be determined due to the dark colored deposits along the fracture surface. No mechanical damage was observed on the remainder of the wheel half assembly (inner).