Answer Example 4 - Flight Plan — Page 104, Lesson 95

I want to walk you through the answers and worked examples for the integrated flight plan and descent calculations. This is where we take all the theory and put it into practice with real numbers. Let's start with Answer Example 4 - Flight Plan. This is a completed integrated flight plan showing how we calculate fuel burn sector by sector. The table has several key columns: Line number, Sector (FROM/TO), Temperature in Celsius, Flight Level, Temperature Deviation, Wind direction and speed, Track (True), TAS, Wind Component, Ground Speed in knots, Nautical Ground Miles, Estimated Elapsed Time, Nautical Air Miles, Gross Start Weight, Cruise Value, Minus NAM, and Fuel. Looking at the worked steps below the table. Step 1: we extract cruise TAS as 430 knots. Step 2: we convert NGM to NAM — that's converting nautical ground miles to nautical air miles, which accounts for the wind effect on the distance the aircraft actually flies through the air. Step 3: we enter the 0.74 Mach cruise table with a Gross Weight of 53,500 kg and extract the Cruise Distance, which is 3,796 nautical air miles. Then we subtract 252 NAM, giving us 3,544 nautical air miles. That 252 NAM is the Minus NAM value from Line 1 of the table. Step 4: we enter the table again with 3,544 nautical air miles and extract the corresponding Gross Weight, which is 52,100 kg. The fuel burn from A to B is then 53,500 minus 52,100 equals 1,400 kg. Step 5: we copy the Minus NAM from Line 1 into the Cruise Value for Line 2 — that's 3,544. Then we subtract 398 nautical air miles, giving us 3,146 nautical air miles. Step 6: we enter the table with 3,146 nautical air miles and extract the corresponding Gross Weight, 50,000 kg. Fuel burn from B to C is 52,100 minus 50,000 equals 2,100 kg. Step 7: we repeat the process for subsequent sectors. Now there are two important notes at the bottom. Note a: the percentage increase or decrease in Fuel Required for 10 degrees Celsius above or below ISA. Note b: the increase or decrease in TAS by 1 knot per 1 degree Celsius above or below ISA. These are the correction factors we apply when temperatures deviate from standard atmosphere. Moving to the Medium Range Jet Transport Detailed Flight Planning section, specifically the Descent Table. This references CAP 697 MRJT1 Figures 4.5.4a and 4.5.4b. The table gives us time, fuel, and distance in nautical air miles for a flight idle thrust descent. Two descent profiles are tabulated: M 0.74/250 KIAS, which approximates to an economy descent, and M 0.70/280 KIAS, which is the turbulent air penetration descent. Allowances are included for a straight-in approach with the undercarriage down. We increase fuel during the descent by 50 kg if engine anti-ice is used. Let's look at Example 5. Given a landing weight of 54,900 kg and a mean descent wind component of 50 knots headwind, we need to calculate the time, fuel, and ground distance for an M 0.74 descent from Flight Level 330. The blanks are: Fuel in kg, time in minutes, distance in nautical air miles, and distance in nautical ground miles. Example 6: an aircraft with an estimated landing weight of 48,500 kg descends from Flight Level 310 to fly a straight-in approach through turbulent air with engine anti-ice on. The wind component is 45 knots tailwind. We calculate fuel burn, time, and ground distance. Same blanks: Fuel in kg, time in minutes, distance in nautical air miles, and distance in nautical ground miles. The answers to Examples 5 and 6 are on page 104. Finally, we have Exercise 1 Flight Plan — an integrated flight plan template for you to complete. The table has seven lines from A at 3,000 feet to TOC, then TOC to B, B to C, C to D, D to TOD, and TOD to E at Mean Sea Level. Below the route fuel line, we have lines for percentage increase or decrease, diversion fuel, 5% contingency fuel, APU/taxi fuel at 260 kg, air conditioning, anti-ice, holding fuel, and finally ramp fuel. This is the complete fuel planning structure you'll use to calculate the total fuel required for a flight.