FAA Aircraft Dispatcher Practice Exam

Which of the following is NOT a criterion for issuing a SIGMET?

1. Extreme icing

2. Severe turbulence

3. Widespread dust storms

4. Light rain

The correct answer is: Light rain

The classification of a SIGMET, or Significant Meteorological Information, is based on specific criteria that denote hazardous weather conditions to aviation safety. The correct answer, which indicates a condition that does not warrant a SIGMET, is light rain. Light rain generally does not present significant hazards to aircraft operations and is instead considered a routine weather phenomenon. In contrast, extreme icing, severe turbulence, and widespread dust storms are conditions that can severely affect flight safety and are categorized as significant weather phenomena. Extreme icing can affect aircraft performance and safety dramatically; severe turbulence poses risks during flight and can cause structural stress; and widespread dust storms can severely reduce visibility and create dangerous landing and take-off conditions. Therefore, these phenomena qualify for a SIGMET, serving as crucial alerts for pilots and dispatchers to make informed decisions regarding flight safety.