CHAPTER 13. Abnormal and Emergency Procedures

Recognition

A VFR pilot is in IMC conditions anytime he or she is unable to maintain aircraft attitude control by visual reference to the natural horizon, regardless of the circumstances or the prevailing weather conditions. Additionally, the VFR pilot is in IMC any time he or she is inadvertently or intentionally and for an indeterminate period of time unable to navigate or establish geographical position by visual reference to landmarks on the surface. These situations must be accepted by the pilot involved as a genuine emergency requiring immediate action.

As discussed earlier, when entering conditions in which visibility is decreasing or IMC, the pilot should turn around, climb, or descend immediately and return to where ground visibility is known. Do not continue assuming that conditions will clear and visibility will be regained.

Maintaining Aircraft Control

Once the pilot recognizes and accepts the situation, he or she must understand that the only way to control the aircraft safely is by using and trusting the fl ight instruments. Attempts to control the aircraft partially by reference to fl ight instruments while searching outside the fl ight deck for visual confi rmation of the information provided by those instruments results in inadequate aircraft control. This may be followed by spatial disorientation and complete loss of control.

The most important point to be stressed is that the pilot must not panic. Recognize the situation and take immediate action. The task at hand may seem overwhelming, and the situation may be compounded by extreme apprehension. The pilot must make a conscious effort to relax and understand that the only concern at this point is to fl y toward known visibility. If climbing into a cloud, reduce throttle and descend. If descending into a cloud, increase throttle and climb out of the cloud. If visibility is suddenly lost (e.g. fl ying into a cloud), turn 180° and fl y toward known visibility.

The pilot should remember that a person cannot feel control pressures with a tight grip on the controls. Relaxing and learning to control with the eyes and the brain instead of muscles usually takes considerable conscious effort.

The pilot must believe that the fl ight instruments show the aircraft’s pitch attitude and direction regardless of what the natural senses tell. The vestibular sense (motion sensing by the inner ear) can confuse the pilot. Because of inertia, the sensory areas of the inner ear cannot detect slight changes in aircraft attitude nor can they accurately sense attitude changes which occur at a uniform rate over a period of time. On the other hand, false sensations are often generated, leading the pilot to believe the pitch attitude or direction attitude of the aircraft has changed when, in fact, it has not. These false sensations result in the pilot experiencing spatial disorientation.

 
 
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