The 737-400, relative to the 737-300, has body stretch of 120 inches, tow additional over wing exit, tail skid, and strengthened landing gear.

400与737-300相比较，机身伸长了120英寸，多了两个逃生出口，尾部滑轨及加强了起落架。

Since the transfer functions between the control fin deflection and overload ot Tail-controlled Skid-to-Turn missiles are of nonminimum phase, zero dynamics is unstable.

零动态解开法是一种回路变换法，通过变换将一个对不稳定对象进行镇定的控制器变换成对非最小相位系统的控制器。