Medium Range Jet Transport (MRJT) Detailed Flight Planning — Page 85, Lesson 88

I want to walk you through the start of the Medium Range Jet Transport (MRJT) detailed flight planning section. This is where we get into the real numbers for fuel planning. First, let me orient you to the reference material. The CAP 697 MRJT1 Figures 4.5.1 through 4.5.4b, covering pages 19 to 70, contain the full set of performance tables we'll use. The section lists what's available: four en route climb tables covering ISA -15°C to +25°C, one wind range correction graph, eleven long range cruise tables from FL270 to FL370, seventeen Mach 0.74 cruise tables from FL210 to FL370, six Mach 0.78 cruise tables from FL290 to FL390, eight low level cruise 300 KIAS tables from FL140 to FL210, and two descent tables. Let's focus on the en route climb, referring to CAP 697 MRJT1 Figure 4.5.1. The CAP 697 provides climb tables for that temperature range of -15°C to +25°C. From these tables, you extract fuel, time, distance in nautical air miles, and TAS. You find these values at the intersection of the cruise pressure altitude and the brake release weight. If your cruise altitude or weight falls between the tabulated values, you must interpolate for intermediate levels and weights. Now, a critical point about what these values represent. The fuel and time figures are measured from brake release — that's the moment you release the brakes at the start of the takeoff roll. The distance is measured from 1500 feet above the airfield, not from brake release. The scheduled climb speed is 280 KIAS up to the Mach transition, then 0.74 Mach — so 280 KIAS/.74 MACH. The tabulated TAS is the climb average TAS. You use this to convert nautical air miles, or NAM, into nautical ground miles, or NGM. Here's the formula: NGM equals NAM multiplied by average TAS, plus or minus the wind component, all divided by average TAS. Let me read that equation naturally: NGM equals NAM times average TAS plus or minus wind component, divided by average TAS. So the wind component is added if it's a tailwind, subtracted if it's a headwind, and the average TAS in the denominator normalizes the ratio. There's also a minor fuel adjustment table below the main climb table. This is for when you're departing from an airfield that is not at mean sea level — so if your airport elevation is above or below sea level, you use that adjustment. Let's work through Example 1 together. Given: brake release weight of 62,000 kilograms, airport elevation at mean sea level, zero wind, ISA -10°C, and you're cleared to a cruise pressure level of 33,000 feet. The task is to calculate the en route climb data: the time in minutes, the fuel burn in kilograms, the NGM, and the average TAS in knots. The answer is on page 104 of the CAP 697. So the process is: you enter the climb table for ISA -10°C, find the column for cruise pressure altitude 33,000 feet, and the row for brake release weight 62,000 kg. At that intersection you read fuel, time, nautical air miles, and average TAS. Since the wind is zero, the NGM calculation simplifies — with zero wind component, NGM equals NAM. Then you have your complete climb segment data for the flight plan.