ATPL General Navigation - Class 6: Distance.

Summary

In this informative aviation class, Grant explains the various units used to measure distances in the field. He clarifies the use of nautical miles for long distances, converting them to meters, kilometers, and feet, and highlights the 1852 meters equivalence of a nautical mile. The video also touches on the use of statute miles in the United States and the conversion between different units. Grant simplifies the concept with practical examples, such as runway dimensions and ILS approach diagrams, and shares a helpful trick for descent planning based on a three-degree slope, which equates to a thousand feet every three nautical miles.

Takeaways

• 🌐 Units in aviation for measuring distance can be confusing due to the variety used, but they are specific to the context, such as altitude in Europe often being measured in feet.
• 🚀 Long distances are typically measured in nautical miles, which are based on a minute change in latitude and equate to 1852 meters or 1.852 kilometers.
• 📏 The conversion between nautical miles and feet is 60.76 feet per nautical mile, and one meter equals 3.28 feet for conversions between meters and feet.
• 🔢 To convert nautical miles to kilometers, multiply the nautical miles by 1.852, and to convert to feet, multiply by 60.76 and then by 3.28.
• 🇺🇸 In the United States, the statute mile is also used for measuring distance, with one statute mile equaling 1.609 kilometers or 1609 meters.
• 📐 For short distances, measurements are generally in feet or meters, and the conversion between them is straightforward using the 1 meter to 3.28 feet ratio.
• ✈️ Runway dimensions and vertical heights, such as threshold elevation, are often given in feet for aviation purposes.
• 📊 The side view of an ILS approach illustrates the use of feet for vertical distances, with a common slope of three degrees equating to a descent of 1000 feet every three nautical miles.
• 🌁 Aviation visibility minima are given in both feet and meters/kilometers, indicating the required cloud base and visibility for different types of approaches.
• 📉 The three-degree slope trick is a helpful tool for descent planning in aircraft, simplifying the math for pilots when descending towards an airport.
• 📝 While the three-degree slope trick might not be on exams, it's a practical tip for pilots to ensure they are on the correct vertical path for landing.

Q & A

What is the main topic of the video class presented by Grant?

The main topic of the video class is the range of units used in aviation to describe various distances, with a focus on conversions between different units.

Why are specific units used for specific measurements in aviation?

Specific units are used for specific measurements in aviation to ensure accuracy and standardization in describing distances, which is crucial for safety and efficiency in flight operations.

What is the definition of a nautical mile according to the video?

A nautical mile is defined as one minute change in latitude and is equivalent to 1852 meters or 1.852 kilometers, and also equals 6076 feet.

How can you convert nautical miles to kilometers?

To convert nautical miles to kilometers, you multiply the number of nautical miles by 1.852, since one nautical mile is equal to 1.852 kilometers.

What is the conversion factor between meters and feet?

The conversion factor between meters and feet is that one meter equals 3.28 feet.

Can you provide an example of converting five nautical miles to kilometers and feet as shown in the video?

Yes, five nautical miles times 1.852 equals 9.26 kilometers. To convert to feet, you would multiply 9260 meters by 3.28 to get 30,372.8 feet.

What is a statute mile and how does it differ from a nautical mile?

A statute mile is a unit of distance used in the United States and is equal to 1.609 kilometers or 1609 meters. It differs from a nautical mile, which is longer and used primarily in aviation and marine navigation.

How are short distances typically measured in aviation?

Short distances in aviation are generally measured in feet or meters, using the conversion factor between the two as needed.

What is the significance of the three-degree slope in instrument approaches as mentioned in the video?

The three-degree slope is significant because it simplifies the mathematical calculations for pilots during flight, allowing them to estimate their descent profile easily. For every three nautical miles, the altitude should decrease by approximately one thousand feet.

Can you provide an example of how the three-degree slope is used for descent planning in the video?

In the video, it is explained that if a plane is at 35,000 feet and needs to descend to 2,000 feet, with a three-degree slope, they would need to start descending 99 nautical miles before the runway threshold to achieve a gentle slope towards landing.

What are the units used for measuring visibility and cloud base in the minima for instrument approaches shown in the video?

The units used for measuring visibility and cloud base in the minima for instrument approaches are feet for altitude and a combination of meters/kilometers for visibility.