Jay,
one simple reason.
no one has been killed yet. A little sick but that is the way they operate.
Michelle

Jay Honeck wrote:

After seven (?) incidents of landing gear malfunctions similar to the Jet
Blue incident, why has the FAA not issued an emergency Airworthiness
Directive on the Airbus A320?

Or has an AD been issued, but without the requirement to "ground" them until
they've been repaired?