What happened
NTSB summary, verbatimDuring landing rollout the right main landing gear (RMLG) collasped. The captain reported a normal landing was completed by the first officer and when he took over control of the airplane "the aircraft dropped sharply to the right and we began skidding down the runway with a continous warning horn. I continued braking and the aircraft came to a stop on centerline with a significant right lean." According to the NTSB Materials Laboratory Factual Report, the outer cylinder of the RMLG was fractured through the transition area above the fused section, with the fracture located approximately 19 inches from the upper end of the cylinder. The factual report noted the fracture initiation point "lies in the parting plane for the cylinder forging. The dark spot [fracture initiation point] was orientated transverse to the gear about 28 7/8 inches from the lower end of the cylinder." According to the factual report, multiple inclusions and intergranular cracks were uncovered within the examined fracture sample. The inclusions were mostly oxides of aluminum and calcium and some inclusions contained small sulfides of iron and manganese. The report noted there were fracture features that were consistent with overstress separation "emanating from the dark spot [fracture initiation point] with mostly ductile dimple formations and some cleavage like features."
Photographs
7the aircraft, and what the investigators foundPhotographs are NTSB docket attachments — works of the US government, in the public domain. Captions are the Board’s own.
Probable cause
the Board's determinationThe failure of the right main landing gear due to fatigue.
Sequence of events
1 timed eventsfrom the FDR factual report · claude-fable-5-1 (in-session)- SRN 37,670-37,720landing rollp.2Landing rollout and right main gear collapse plotted: vertical/lateral/longitudinal acceleration, roll, heading, pitch, autopilot, VHF keying, EPR 1 and 2, airspeed, altitude (plot II-1); plus left aileron, control wheel, control column and rudder pedal (plot II-2); no numeric values in the text
NTSB analysis
from the final reportDuring landing rollout the right main landing gear (RMLG) collasped. The captain reported a normal landing was completed by the first officer and when he took over control of the airplane "the aircraft dropped sharply to the right and we began skidding down the runway with a continous warning horn. I continued braking and the aircraft came to a stop on centerline with a significant right lean." According to the NTSB Materials Laboratory Factual Report, the outer cylinder of the RMLG was fractured through the transition area above the fused section, with the fracture located approximately 19 inches from the upper end of the cylinder. The factual report noted the fracture initiation point "lies in the parting plane for the cylinder forging. The dark spot [fracture initiation point] was orientated transverse to the gear about 28 7/8 inches from the lower end of the cylinder." According to the factual report, multiple inclusions and intergranular cracks were uncovered within the examined fracture sample. The inclusions were mostly oxides of aluminum and calcium and some inclusions contained small sulfides of iron and manganese. The report noted there were fracture features that were consistent with overstress separation "emanating from the dark spot [fracture initiation point] with mostly ductile dimple formations and some cleavage like features."