Weight, Balance, and Performance
What this domain tests
This domain tests how suspended weight, canopy area, trim, and environmental conditions affect parachute performance. Questions may ask you to compare wing loading, estimate descent-rate trends, or explain an aircraft weight-and-balance effect.
Core rules and concepts
- Wing loading. Wing loading is suspended weight divided by canopy area, usually expressed in pounds per square foot (lb/ft²). Suspended weight includes the jumper or payload, harness, container, reserve, clothing, and accessories-not just body weight.
- Performance trends. At higher wing loading, a canopy generally flies faster, descends faster, and responds more sharply. At lower wing loading, it is slower and more docile. Canopy design, trim, line length, and porosity also matter.
- Density altitude. High altitude, high temperature, and high humidity reduce air density. A canopy producing the same indicated performance at sea level may descend faster and flare less effectively at high density altitude.
- Trim and configuration. Line trim, brake setting, canopy damage, and harness geometry affect angle of attack and glide. A canopy rigged out of trim may not meet its expected performance even at the correct wing loading.
- Aircraft weight and balance. Parachutes carried as equipment add weight and can shift center of gravity. Follow the aircraft’s approved loading limits; do not assume a parachute is negligible.
Worked example
A jumper’s exit weight is 240 lb with gear. The canopy has 200 ft² of area. Wing loading is 240 ÷ 200 = 1.2 lb/ft². A second jumper has an exit weight of 180 lb under the same canopy: 180 ÷ 200 = 0.9 lb/ft². The heavier jumper should expect a faster descent, higher forward speed, and a less forgiving landing. If the first jumper’s body weight alone were used (for example, 200 lb), the loading would be underestimated as 1.0 lb/ft², which is wrong because gear is suspended too.
Traps that cost marks
- Using body weight instead of exit weight.
- Comparing canopies by advertised size without considering actual trim and condition.
- Ignoring density altitude when explaining descent or flare performance.
- Treating parachute weight as irrelevant to aircraft weight and balance.