Unit Conversion Techniques

In aviation, accurate unit conversion is crucial for safe and efficient flight operations. This section will guide you through essential unit conversions needed for the CASA PPL pilot license theory exam, focusing on common conversions necessary for navigation and computation techniques.

Learning Outcomes

Upon completion of this section, you should be able to:

• Convert between feet and metres.
• Convert between US gallons, litres, and kilograms of aviation gasoline.
• Convert between nautical miles and kilometres.
• Convert between pounds and kilograms.

Length Conversions

Feet to Metres

In aviation, altitudes are often given in feet, especially in the United States. However, you may need to convert these figures to metres, especially during international operations or when using metric-standard countries’ charts.

Conversion Formula:

Example: To convert 10,000 feet to metres:

Sources:

• Conversion Factors - Aerodynamics for Students
• Units & Conversion Factors – Introduction to Aerospace - Embry-Riddle Aeronautical University

Volume Conversions

US Gallons to Litres and Kilograms

Fuel volume is often measured in US gallons, but depending on aircraft specifications and refueling locations, you may need to convert to litres or even kilograms (especially if considering the weight of the fuel for balance and performance computations).

Conversion Formulas:

• ( 1 , \text{US gallon} \approx 3.78541 , \text{litres} )
• Aviation gasoline weight varies; typical avgas weighs approximately 6 lbs/US gallon or about 2.72 kg/US gallon

Example: To convert 50 US gallons of avgas to litres and kilograms:

• Litres: ( 50 , \text{US gal} \times 3.78541 , \text{l/US gal} = 189.2705 , \text{l} )
• Kilograms: ( 50 , \text{US gal} \times 2.72 , \text{kg/US gal} = 136 , \text{kg} )

Sources:

• Conversion Factors - Aerodynamics for Students
• Units & Conversion Factors – Introduction to Aerospace - Embry-Riddle Aeronautical University

Distance Conversions

Nautical Miles to Kilometres

Distances in aviation are typically measured in nautical miles, particularly for navigation and flight planning. However, conversions to kilometres may be necessary for certain international operations.

Conversion Formula:

Example: To convert 5 nautical miles to kilometres:

Sources:

• Conversion Factors - Aerodynamics for Students
• Units & Conversion Factors – Introduction to Aerospace - Embry-Riddle Aeronautical University

Mass Conversions

Pounds to Kilograms

Weights of cargo, passengers, and aircraft components are often presented in pounds within the aviation industry in the United States. Conversion to kilograms might be needed when dealing with metric systems internationally.

Conversion Formula:

Example: To convert 100 lbs to kilograms:

Sources:

• Conversion Factors - Aerodynamics for Students
• Units & Conversion Factors – Introduction to Aerospace - Embry-Riddle Aeronautical University

Conclusion

Understanding and accurately applying these conversions are vital skills for pilots, facilitating safe and precise navigation, fuel management, and operational planning. Practice these conversions regularly to ensure proficiency, especially in scenarios involving international flights where metric and USC systems may interchange. Access to tools such as E6BX Aviation Unit Converters enhances situational readiness for complex calculations.

Pilots can also refer to CASA’s Pilot Guide and similar resources provided by global aviation authorities such as the FAA and EASA for comprehensive conversion tables and further practice in applying these essential skills.