Incident Overview
A flight inbound to land experienced an unsafe nose gear indication. The flight crew was unable to confirm the gear was down and subsequently diverted to Runway 31R at John F. Kennedy International Airport (JFK). The aircraft landed on the runway with the nose gear retracted. An emergency evacuation was performed.
Examination Findings
Post-accident examination of the wreckage revealed that the nose landing gear upper lock link had fractured into two pieces. The fractured linkage jammed against the shock strut structure, preventing extension of the strut. According to the airplane manufacturer, the upper lock link failed due to fatigue.
Material and Design Background
The failed lock link was made from aluminum plating. Originally, all such links were fabricated from forged aluminum. The company later switched to plated aluminum because it weighed less. Although both types of lock links were of the same strength, the aluminum plating fatigued sooner than the forged links.
Corrective Action
Following the accident, the company replaced all aluminum plated upper lock links with forged ones across the fleet.