Flight Performance and Planning: Mass, Balance, Performance, Flight Planning
Mass and balance
Understand the terms: basic empty mass, dry operating mass, take-off mass, landing mass, zero-fuel mass, and maximum values for each. Learn how to compute the centre of gravity using the moment arm method and how to read a loading envelope. Know that the CG must stay within limits for the whole flight, including fuel burn, and that aft CG reduces stability while forward CG increases stall speed and reduces performance.
Performance
Study take-off and landing distance components: ground roll, rotation, screen height, and the effect of density altitude, wind, slope, surface, and mass. Understand climb performance (rate and gradient), the difference between service ceiling and absolute ceiling, and the effect of weight on all of them. Learn the meaning of V-speeds and which are mass-dependent.
Flight planning
Know how to compute true track, wind correction angle, groundspeed, and fuel required including reserve and contingency. Understand the difference between true, magnetic and compass headings, and the use of the flight log. Be able to compute endurance and safe diversion fuel.
Traps
The classic traps are forgetting to include fuel in the landing mass, using the wrong arm sign (datum ahead or behind), and mixing pressure altitude with density altitude. Another is applying a wind component with the wrong sign.
Worked example
Take-off mass 1,100 kg, CG 0.98 m aft of datum. Moving 40 kg of baggage from 0.50 m to 1.60 m shifts the CG by (40 × 1.10) / 1,100 = 0.04 m aft, giving 1.02 m. Rule of thumb: shift = (mass moved × distance moved) / total mass.