Final answer:
An altimeter is an instrument in aircraft used to measure altitude during flight. It is essential for maintaining safe climb and descent rates, as well as ensuring the aircraft clears obstacles and successfully approaches for landing by measuring pressure differences. Pilots must adjust altimeter settings according to local or standard pressure references.
Step-by-step explanation:
Altimeter Functions in Climb and Descent
An altimeter is an instrument used in an aircraft to measure the altitude, the height above a reference point, typically mean sea level. During a climb, the altimeter helps pilots ensure that the aircraft is ascending at the desired rate and clearing any obstacles or terrain. Conversely, during a descent, the altimeter is crucial for maintaining a safe glide path and preparing for landing, ensuring that the aircraft is neither descending too quickly nor risking an undershoot or overshoot of the runway.
The altimeter works by measuring the pressure differences as the aircraft changes altitude. As the plane climbs, the air pressure decreases, and this change is translated into an altitude increase on the altimeter dial or display. During descent, the opposite occurs—the air pressure increases as the aircraft descends, which is shown as a decrease in altitude on the altimeter.
Pilots must frequently adjust the altimeter settings to the local pressure setting (QNH) or the standard pressure setting (QNE) to ensure accuracy. Failure to correctly set the altimeter can result in incorrect altitude readings and dangerous situations.