Summary
We propose to supersede airworthiness directive (AD) 2013-07- 07, which applies to all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. AD 2013-07-07 requires inspecting to determine the part number of the attach pins of the horizontal stabilizer rear spar, and replacing certain attach pins. Since we issued AD 2013-07-07, we received inquiries from affected operators regarding the parts installation limitation and prohibition, and re-installation of certain attach pins that were removed for inspection. This proposed AD would clarify the parts installation limitation and prohibition, and would add a new requirement for certain airplanes on which certain attach pins were installed. We are proposing this AD to prevent premature failure of the attach pins, which could cause reduced structural integrity of the horizontal stabilizer to fuselage attachment, resulting in loss of control of the airplane.