Grand Junction, CO, USA
N114SA
Piper PA-31-350
While on final approach the pilot moved the landing gear lever to the extended position, heard the normal sounds of the gear extending and noted that the three green landing gear position lights were illuminated. However, when he looked at the nose landing gear through the mirror on the left engine cowling, he noted that the nose gear was hanging at a 45-degree angle. The pilot attempted to cycle the gear, and the nose landing gear did not move. The pilot executed a go-around. The pilot attempted to use the emergency gear extension procedure, contacted various maintenance facilities via aircraft radio, and then performed a low fly-by of the air traffic control tower (ATCT). The ATCT controllers were able to see that the main landing gear appeared to be down and locked; however, the nose landing gear was hanging at a 45-degree angle. During the ensuing landing, the nose gear collapsed, and the pilot brought the airplane to a stop on the runway. Examination revealed that the airplane's nose landing gear right drag brace (link assembly) was separated. The NTSB examined the fracture surfaces and observed a banding pattern on both fracture surfaces, consistent with fatigue. Ratchet marks indicated that the fatigue initiated from machining marks located in the blend radius between the narrow edge of one of the idler link lugs and the adjacent surface of the link.
On July 29, 2001, at 0915 mountain daylight time, a Piper PA-31-350 airplane, N114SA, was substantially damaged during an emergency landing at the Walker Field Airport, Grand Junction, Colorado. The airplane was registered to and operated by American Aviation, Inc., of Salt Lake City, Utah. The airline transport pilot, sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed, and a visual flight rules flight plan was filed for the 14 Code of Federal Regulations Part 135 scheduled cargo flight. The flight originated from the Salt Lake City International Airport, Salt Lake City, Utah, at 0800, and was destined for Grand Junction. The pilot reported that while on final approach to runway 04, at Grand Junction, he moved the landing gear lever to extend the landing gear, heard the normal sounds of the gear falling into place, and noted that the three green landing gear position lights were illuminated. However, when he looked at the nose landing gear through the mirror on the left engine cowling, he noted that the nose gear was hanging at a 45-degree angle. The pilot attempted to cycle the gear, and the nose landing gear did not move. The pilot executed a go-around. The pilot attempted to use the emergency gear extension procedure, contacted various maintenance facilities via aircraft radio, and then performed a low fly-by of the air traffic control tower (ATCT). The ATCT controllers were able to see that the main landing gear appeared to be down and locked; however, the nose landing gear was hanging at a 45-degree angle. During the ensuing landing on runway 04, the nose gear collapsed, a bulkhead in the nose area was buckled, and the airplane came to a stop on the runway. An FAA inspector, who examined the airplane, found that the nose landing gear right drag brace (link assembly) was separated. The link assembly was removed from the airplane and sent to the NTSB Materials Laboratory in Washington, D.C. for further examination. The NTSB's examination of the fracture surface revealed a banding pattern on both fracture surfaces, consistent with fatigue. The fracture surfaces were cleaned, which revealed machining marks in the blend radius between the narrow edge of one the idler link lugs and the adjacent surface. The fatigue region contained multiple ratchet marks, indicating that there were multiple fatigue initiation sites.
the failure of the nose landing gear right drag brace (link assembly) due to fatigue.
Source: NTSB Aviation Accident Database
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