Medium-Long Haul – The Methodology Calculations for Fuel Cost Saving

1. Establishing the Assumptions

Before diving into the math, we start by laying out all the assumptions:

• Flight Distance for a Typical Medium/Long-Haul Aircraft: 3,500 km per flight
• Fuel Savings Factor: It is assumed that reducing the weight by 1 kg saves about 3 grams (0.003 kg) of fuel per kilometre flown. This rule-of-thumb is based on typical performance data and aerodynamic considerations.
• Flight Frequency: 250 flights per year
• Fuel Cost: $0.675 per kg of fuel.

These assumptions simplify the real-world complexities of aircraft operations but provide a good baseline for estimation.

2. Calculating Fuel Savings per Flight

The first step is to determine how much fuel is saved on a single flight when the aircraft’s weight is reduced by 1 kg.

Step 2.1: Apply the Fuel Savings Factor

For every kilometre flown, a 1 kg weight reduction saves 0.003 kg of fuel. Therefore, for a flight covering 3,500 km:

Fuel saved per flight = 3,500 km × 0.003 kg/km = 10.5 kg

Thus, each flight saves approximately 10.5 kg of fuel.

3. Estimating Annual Fuel Savings

Next, we extend the per-flight savings to an annual figure by incorporating the number of flights the aircraft makes in a year.

Step 3.1: Multiply by Annual Flight Frequency

Annual fuel savings = 10.5 kg/flight × 250 flights = 2,625 kg

So, over the course of one year, a 1 kg weight reduction would save approximately 2,625 kg of fuel.

4. Converting Fuel Savings into Cost Savings

Finally, we translate the fuel savings into a monetary value using the given fuel cost.

Step 4.1: Multiply by Fuel Cost per Kilogram

Annual cost savings = 2,625 kg × $0.675 per kg ≈ $1,772

Rounded off, the annual savings are roughly $1,772.

5. Considerations and Caveats

• Rule-of-Thumb Estimate: The factor of 0.003 kg fuel saved per km per 1 kg weight reduction is a simplified estimate. Actual savings can vary based on flight conditions, aircraft configuration, and operational procedures.
• Flight Profile Variability: Different flight distances, altitudes, or weather conditions could alter the fuel burn rate.
• Operational Factors: The frequency of flights, actual route distances, and variations in fuel prices can all impact the final cost savings.
• Aerodynamic and Engine Efficiency: The effect of weight reduction is non-linear in practice; changes in drag and engine performance might slightly alter the savings compared to this simple calculation.

Conclusion

In summary, under the assumed conditions—a 3,500 km medium-haul flight on a typical medium/long-haul aircraft, 250 flights per year, a fuel savings factor of 0.003 kg/km per 1 kg weight reduction, and a fuel cost of $0.675 per kg—a 1 kg weight reduction would save:

• 10.5 kg of fuel per flight
• 2,625 kg of fuel per year
• Approximately $1,772 in fuel cost annually

This expanded methodology shows how to combine operational assumptions, per-flight fuel savings, and annual flight frequency to arrive at an estimated annual cost savings from a small weight reduction.

Note:
This is a simplified estimation. In practice, fuel savings will depend on many factors such as the actual flight profile, atmospheric conditions, aircraft configuration, and how the weight reduction affects overall aerodynamics and performance.