Weight and Balance for Large Airplanes

Why is CG often expressed as a percentage of MAC in large aircraft?

Tapered and swept-back wings make chord length vary

What is the primary reason a technician who understands small aircraft weighing can apply the same principles to large aircraft?

The fundamental weight and balance concepts remain the same regardless of scale

In the event of a maintenance event altering structure, what must be updated?

The aircraft equipment list and weight & balance report

What is the formula for converting % MAC to CG in inches?

(% MAC ÷ 100 × MAC) + LEMAC

What purpose does expressing CG as % MAC serve for flight crews?

Allows standardized entry into performance software

What advantage does using % MAC offer when designing performance envelopes?

Allows CG limits to be scaled across similar designs

What condition must be met for FMS weight data to be considered reliable in the Boeing 777?

Data must be identical from both weighing systems

When using a sample form for weight data, which section changes for taildraggers vs tricycle gear?

The nose/tail gear row

Why would a four-column method be used instead of six when updating weight without reweighing?

Because tare weight and fluids are not involved

Why are traditional weighing methods still used despite electronic systems?

Aircraft with no onboard systems still require weighing

In the Boeing 777, how is the accuracy of weight and CG verified before dispatch?

Comparison of two independent onboard systems

Why are electronic load cells significant in large aircraft weight and balance procedures?

They enable self-weighing while the aircraft is on the ground

What differentiates the use of jacks and scales in large aircraft compared to small aircraft?

Larger equipment and more personnel are required

What defines the mean aerodynamic chord (MAC) on a large aircraft?

The average chord length across a tapered, swept-back wing

Why is expressing CG as a percent of MAC useful in large aircraft?

It standardizes CG regardless of aircraft size

What FAA requirement exists concerning aircraft weight and balance data?

It must be current, accurate, and available onboard

What does LEMAC represent in CG calculations?

Leading edge of the MAC from the datum

Which aircraft configuration would most likely require a different weight and balance form layout?

Helicopter

Which step must be performed first when converting CG from inches to percent MAC?

Subtract the LEMAC from the CG location

What action is necessary if weight and balance are altered but the aircraft is not reweighed?

Calculate the change using weight shift equations

How does an electronic load cell transmit weight data?

As electrical signals to the FMS

What aspect of a swept-back wing makes using inches for CG less effective?

Variable chord length from root to tip

If MAC is 200 inches and CG lies 50 inches behind LEMAC, what is the CG as % MAC?

25%

What should be used to record a new EW and EWCG after changes?

Weight and balance report form

When is a technician most likely to calculate EW and EWCG?

When a new piece of equipment is installed