FAA Private Pilot Airplane (PAR)Performance, Weight and BalanceHard
An aircraft has an empty weight of 1,500 lbs and an empty weight center of gravity (CG) at 85.0 inches aft of the datum. A pilot weighing 170 lbs and a passenger weighing 130 lbs are onboard. The aircraft has a baggage compartment aft of the datum at a station of 120 inches. If the maximum allowable CG is 90.0 inches, what is the maximum weight of baggage that can be loaded without exceeding the aft CG limit, assuming all other items are already accounted for and the total weight remains within limits?
- A45 lbs
- B60 lbs
- C30 lbs
- D75 lbs
Show answer & explanationAnswer & explanation
Correct answer: B. 60 lbs
This requires calculating the current moment, then determining how much baggage weight at the baggage compartment's arm can be added to shift the CG to the maximum allowable aft limit without exceeding it. The pilot and passenger's arms are needed for the full calculation, but since we're only focused on the aft limit with baggage, we need to solve for the unknown baggage weight.
Why the other options are wrong
- A. Incorrect. This value is likely obtained by an error in moment calculation or solving the equation.
- C. Incorrect. This value is likely obtained by an error in moment calculation or solving the equation.
- D. Incorrect. This value is likely obtained by an error in moment calculation or solving the equation.
CG Shift Calculation
Determining how much weight can be added or removed at a specific location to keep the aircraft's center of gravity within its allowable limits.
- Uses the principle of moments: Weight x Arm = Moment.
- The sum of all moments divided by the sum of all weights gives the overall CG.
- Solving for an unknown weight or location often involves algebraic manipulation of the moment equation.
Memory trick: Moment balance: current + new equals total at limit.