Chapter 19 covers emergencies that involve analysis, Chapter 4 covers emergencies that requiring more immediate, essentially automatic, action.

Feeling unwanted wing turn just as you lift off, for example, is a Chapter 4 type immediate action emergency. Students should learn a few of these in the simulator before their first flight which is why they’re in Chapter 4.

In any emergency: FLY THE CRAFT!

The most important thing to do when something unexpected happens in flight is fly the craft! Don’t do anything rash and do not just yank on those brakes. Analyze the problem long enough to carry out the correct action. About the only time an immediate action may be required is when you hear something amiss with the motor. Even then you want to think for a second before acting at a potentially inopportune time. For example, a muffler rubbing into the prop is bad but might take 5 seconds to break the prop. If you’re about to run into power lines, that could be a very valuable 5 seconds of thrust.

As experience is gained and proper reactions are developed then they will become immediate. But reacting to a situation before that point almost always accentuates the outcome.