When I worked at AirTran Airlines from 1998-2000, a mechanic deferred one thrust reverser on the 737-200 and it went badly! The manuals were hard to read and it told him to cap a hydraulic line, but it wasn't clear which one. He consulted with tech and made the choice. The plane took off leading to an emergency landing because he had lost all hydraulic pressure. He landed drifting off the runway into the grass and almost went over a cliff at KATL. People had broken bones but no-one died. The plane was destroyed after the hard landing...Glad we have digital books now!!