Weight & Balance Flashcards

An aircraft weighs 3,200 lb with a CG at 95.0 inches. A 50 lb item is removed from a station 120.0 inches aft of datum. What is the new CG?

Answer: 94.6 inches

New weight = 3,150 lb; Moment removed = 50×120 = 6,000; New moment = (3,200×95) – 6,000 = 298,000; CG = 298,000÷3,150 ≈ 94.6 inches.

What is 'zero fuel weight'?

Answer: Maximum allowable weight with no usable fuel on board

Zero fuel weight is the maximum certificated weight of the aircraft without usable fuel, establishing structural limits for wing bending loads.

When fuel is burned during flight, how does the CG typically shift in a high-wing aircraft with wing tanks?

Answer: CG moves forward

In most high-wing designs, wing fuel is located forward of the CG, so as fuel burns off, the CG moves forward.

The term 'useful load' is defined as the difference between:

Answer: Maximum gross weight and basic empty weight

Useful load = Maximum Gross Weight – Basic Empty Weight, and represents the total payload the aircraft can carry.

A helicopter weight and balance calculation differs from a fixed-wing calculation primarily because helicopters must also consider:

Answer: Lateral CG limits in addition to longitudinal CG

Helicopters have both longitudinal and lateral CG limits due to the need for cyclic trim authority, making lateral balance critical.

What is the significance of the 'arm' in weight and balance calculations?

Answer: The horizontal distance from the datum to a component's center of gravity

The arm is the horizontal distance measured from the datum to the point where the weight acts, used to compute moment.

An aircraft has a MAC of 60 inches. The LEMAC is at fuselage station 128. If the CG is at station 146, what is the %MAC?

Answer: 30% MAC

%MAC = ((CG station – LEMAC) ÷ MAC) × 100 = ((146 – 128) ÷ 60) × 100 = 30%.