Aviation Altitudes – The Importance of Aircraft Altimeters in Aviation Safety:
Simple is altitude. You know, just your height above the ground. If you’re a pilot, no.
In aircraft, there are numerous sorts of altitude. All types of altitude, how to measure or calculate them, and how to use them during flight must be taught to new student pilots.
In order to produce a “types of altitude explained for pilots” guide, we are going over the entire list today. We’ll start with the most popular and frequently utilized types before moving on to a few you might not even be familiar with.
How many types of altitude exist?
Most articles on pilot training focus on the five categories of altitude that are included in official training and testing, although there are actually many more.
The several forms of altitude that we will be discussing today are listed below:
5 Types of Altitude Pilots Are Tested On:
Pilots must have a basic knowledge of five different types of altitude in order to pass their written exam and check rides. Here are the definitions, measurement methods or calculation formulas, and purposes of each of the primary types of altitude.
The altitude reading that appears on your aircraft’s altimeter is known as the “indicated altitude.” It is an extrapolated estimate that accounts for atmospheric conditions and your elevation above sea level.
How to Measure Indicated Altitude: The pressure altimeter on your aircraft measures the air pressure at your height and calculates your altitude using the input from the altimeter setting.
Utilization of Indicated Altitude: Aerial separation is maintained via indicated height. It is also essential for pilot math equations.
What is pressure and elevation?
The indicated height known as pressure altitude is the elevation above the standard datum plane, which is a hypothetical atmospheric level where the atmospheric pressure is 29.92″ Hg. It could also be known as adjusted barometric altitude.
Calculating pressure and elevation: Enter the current local barometric pressure reading into your altimeter’s settings before takeoff. Your pressure altitude is now displayed on your altimeter gauge.
Note: Pilots set the altimeter to 29.92 inches of mercury (standard pressure altitude) rather than local barometric pressure readings while flying at 18,000 feet or higher to maintain standardization.
Uses for Pressure Altitude: Pressure altitude is used to standardize high altitude flight levels and to calculate aircraft performance parameters like density altitude. It is also used to decide whether or not additional oxygen should be worn.
Pro Tip: Pilots of today can check the pressure and altitude from their wrist. Pilots can easily wear the sophisticated Garmin D2 Air X10 smart watch, which is fashionable and functional. The Air X10 includes a barometric altimeter in addition to navigation, weather, airport data, flight logging, health monitoring, and other features.
What is Density Altitude?
Definition of Density Altitude: Density altitude isn’t exactly a measure of altitude. Instead, it is the altitude at which air density is stated. Regardless of your actual altitude, your aircraft will behave as though it is flying at a density altitude. A greater density altitude equals poorer airplane performance.
Density Altitude Formula: Density altitude is pressure altitude that has been adjusted for abnormally high or low temperatures and humidity levels. For every 1,000 feet above the reporting altitude, the density altitude is roughly estimated to be 4 feet per degree Celsius over standard temperature.
Uses for density altitude: You can predict your aircraft’s performance based on the environment by using density altitude. Density altitude is a factor in takeoff distance, climb rate, and weight calculations, among other things. On warmer days, density altitude rises, and on cold days, it falls. Summer pilots pay strict attention to density altitude, particularly when flying over mountains.
Other Types of Altitude:
This second batch of altitude types aren’t as commonly referenced and don’t appear on most “types of altitude” lists for pilots, but we still use them frequently.
What is Pivotal Altitude?
Pivotal altitude is defined as “the specific altitude at which, when an airplane turns at a given ground speed, from the pilot’s point of view, the plane’s wingtip appears to pivot around a single fixed reference point on the ground” in our post Pivotal Altitude Explained (Everything You Need to Know).
Formula for Pivotal Altitude: Uses for pivotal altitude: Ground speed in miles per hour (2/15) or ground speed in knots (2/11.3) Master the “Eights on Pylons” ground reference maneuver while learning precise aircraft management.
What is Transition Altitude?
Transition altitude, sometimes known as TA, is the height above mean sea level (MSL) at which pilots set their altimeters to the standard pressure setting of 29.92 instead of the local barometric pressure.
The transition altitude, sometimes referred to as FL180 or flight level 180, is 18,000 feet MSL.
Uses for Transition Altitude: To ensure that all aircraft flying at the same altitudes are utilizing the same altimeter settings, transition altitude is utilized. This allows air traffic control to safely maintain pressure-based separation.
What is Relative Altitude?
Relative altitude is defined as your altitude in relation to the altitude of another aircraft or other comparable reference point.
Uses for Relative Altitude: In holding patterns and landing sequences, comparing the relative heights of two aircraft can help determine vertical separation or location.
What is Geometric Altitude?
Geometric altitude is a computed aircraft altitude that is used by the EGPWS Terrain Awareness and Display systems on board.
Formula for Geometric Altitude: The computer uses standard altitude, radio altitude, GPS altitude with vertical figure of merit (VFOM) and RAIM failure indication, to calculate geometric altitude. In addition, if available, ground speed, roll angle, location, static air temperature, and pressure altitude are employed.
Uses for Geometric Altitude: Geometric altitude is used to allow pilot to continue operation and determine altitude when one or more of the standard pilot altitude measurements is not available.
Calibrated Altitude: What Is It?
Definition of Calibrated Altitude: Calibrated altitude is the indicated altitude when it has been corrected for errors including static pressure error, instrument error, and installation error.
Here are some explanations and answers to some of the most perplexing altitude ideas before we finish.
True Altitude vs Absolute Altitude:
True height, which refers to your vertical elevation above sea level (feet MSL), and absolute altitude, which refers to your vertical elevation above the ground, are two different things (feet AGL).
Is the difference between indicated and true altitude ever zero?
Confusion might arise when comparing apparent altitude to true altitude. True and indicated heights during actual flights are extremely rarely the same, but it is possible. It would be necessary for you to be flying under normal pressure circumstances for these two altitudes to be equal.
It’s important to keep in mind that when you fly in cooler weather, displayed height is more likely to diverge significantly from true altitude. Your indicated altitude will be higher than your true altitude under extremely cold conditions. If pilots are not alert, this could be dangerous and lead to controlled flying into terrain (CFIT).
What distinguishes pressure altitude from density altitude?
New student pilots may be perplexed about the difference between density altitude and pressure altitude due to the names’ similarity. Remember that density altitude takes pressure altitude and then corrects for the effects of temperature and humidity.
More Altitude-Related Reads
How to Read an Altimeter (Complete Guide)
Pitot-Static System: How does it work?
Coffin Corner: Reaching Beyond the Limitations
Which kind of altitude was the most challenging for you to comprehend as a beginning pilot? Which sorts still give you trouble today? What suggestions do you have for keeping in mind the distinctions between them?