Why Airplanes Measure Altitude in Feet but Mountains in Meters: An Insight into Aviation and Navigation
The measurement of altitude in aviation and geography often differs between airplanes and mountains, with the former using feet and the latter using meters. This discrepancy arises from a combination of historical, regulatory, and practical reasons. Understanding these reasons can help us better appreciate how aviation and mountain navigation systems work.
The Measurement of Altitude in Aviation
When it comes to airplanes, the altitude is typically measured in feet, a measurement rooted in the tradition of the aviation industry. This is not just a zero-sum game of convenience, but a reflection of historical and regulatory factors.
For instance, cruisings altitudes for passenger jets are well above the heights of most mountains, thus avoiding the need to navigate around them. However, for small general aviation aircraft, pilots face different challenges. These aircraft, often equipped with propellers and seating up to four people, operate at lower altitudes where they need to be wary of obstacles such as mountains and other terrain features.
Navigational Maps and Altitude Measurement
Pilots use specialized navigational maps called sectional charts to plan their routes. These charts, unlike hiking maps, do not provide detailed elevation data but instead offer shaded relief of the terrain and obstacle heights, such as radio towers. The maps are divided into large rectangles, and in each rectangle, a number is provided. This number represents the Minimum Safe Altitude (MSA), which is the height above which pilots are considered to be safe from terrain and obstacles.
Minimum Safe Altitudes and Flight Levels
MSAs are published in feet, catering to the altimeter in the aircraft, which also measures altitude in thousands and hundreds of feet. The use of feet in aviation is further reinforced by the use of Flight Levels, a standard for defining altitudes in the flight deck. A Flight Level (FL) is expressed as a number of hundreds of feet. For example, FL 390 is 39,000 feet. This system ensures consistency and simplifies navigation for pilots.
The Global Perspective on Height Measurement
While the aviation industry predominantly uses feet, the world is moving towards a more metric system for terrain measurement. Russia, for instance, measures altitudes in meters, and many crest points of the world are transitioning to this system. The metric system is more convenient and logical for scientific calculations, but centuries of habit have ingrained the use of feet in aviation.
Going Deeper: The History and Logic Behind Feet and Meters
The use of feet in aviation is not as illogical as one might believe. It is rooted in historical tradition and practical necessity. For instance, traditional flight levels are described in hundreds of feet. Flight Level 390, for example, is 39,000 feet. This system allows for seamless communication and clear understanding among pilots.
Conclusion: Understanding the Duality of Height Measurement in Aviation and Geography
The measurement of altitude in aviation and geography is a reflection of historical, regulatory, and practical factors. While mountains are typically measured in meters, aircraft primarily use feet due to tradition, regulation, and the need for simplicity in navigation. Understanding these differences can help us appreciate the complexity and ingenuity of the aviation and geographical systems we use today.