Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-700 and -700C series airplanes. This proposed AD was prompted by a report that for airplanes with blended winglets, the nose-up pitch trim limit and associated warning for the horizontal stabilizer control system will allow take-off with incorrect trim settings. This proposed AD would require, depending on airplane configuration, replacing the pitch trim light plates on the flight deck control stand, relocating the position warning horn switches of the horizontal stabilizer, revising the software, removing the placard, and doing related investigative and corrective actions if necessary. We are proposing this AD to prevent take-off with incorrect settings of the horizontal stabilizer pitch trim system. Settings outside of the appropriate pitch trim limits could result in loss of controllability of the airplane during take-off.