Читать книгу Flight Theory and Aerodynamics - Joseph R. Badick - Страница 57

Absolute altitude is the vertical altitude above the ground (AGL), and can be measured with devices like a radar altimeter. Of course, your absolute altitude is more critical the closer to the ground you are flying; so even when not equipped with a radar altimeter, a pilot should be aware of their AGL altitude. When conducting an instrument approach in inclement weather, knowledge of your AGL altitude is vital to the safe completion of the approach or execution of a missed approach. Your height above airport (HAA), height above touchdown zone (HAT), and decision height (DH) are all AGL altitudes and should be briefed before the approach.