How did the nose landing gear of JetBlue Flight 292 get stuck sideways?
According to the complete NTSB report, following is a summary of what had caused the nose landing gear (NLG) to rotate 90° on Flight 292.


  During flight, Brake Steering Control Unit (BSCU) performs1
  cyclic tests which slightly rotates NLG from the 0° position. Due to
  this fatigue, two of the four anti-rotation lugs on the NLG upper
  support assembly fractured and separated. This allowed NLG to deviate
  from the 0° position. Another contributing factor was BSCU system
  logic, which prevented NLG from centering. Also contributing was the
  lack of a procedure to attempt to reset the BSCU system under these
  conditions.


This website has some nice pictures of nose landing gear before and after the landing.

A summary of the investigation can be found here.



1: BSCU has other functions too.