Incident Overview
Moments after touchdown, the left main landing gear collapsed. The captain and first officer reported the touchdown was normal, but all three flight attendants stated the aircraft landed hard and began shaking severely. The flight attendants also noted that the two previous landings had caused significant vibration and shaking.
Wind Conditions
The tower reported winds from 350 degrees at 19 knots, gusting to 29 knots.
Component Examination
Examination of the left main landing gear revealed that the tee bolt had separated. Metallurgical analysis of the tee bolt showed that the fracture originated from a shallow preexisting crack in the drag brace bearing surface radius. The metallurgist found the radius to be sharper than desired.
Finding
The collapse of the landing gear is considered related to the fractured tee bolt. The safety board was unable to determine whether other events, circumstances, or conditions contributed to the tee bolt failure in this instance.
Operator Action
In response, the operator has amended its repair specifications for the tee bolts.