The Federal Aviation Administration said it would seek more detailed inspections for cracks on the tops of Boeing 737-300, 400, and 500 series aircraft. This is a direct result of a hole that tore open in a Southwest Airlines jet back in 2009.
They will be expanding rules to include new inspection methods with scanning technology, checks of more areas of the plane, the installation of additional reinforcements and checks for loose fasteners.
The proposal for these changes came in January of 2012, endorsed by the NTSB, and the new inspections are already underway according to Boeing, with few findings of additional problems.
These planes are older, but 737s fly all over the world, and while the incident in 2009 did not result in any injuries, it is better to ensure future incidents do not.