Question

practice weight and balance quiz question 36 of 50
the following alteration was performed on an aircraft: a model b engine weighing 175 pounds was replaced by a model d engine weighing 185 pounds at a -62.00 - inch station. the aircraft weight and balance records show the previous empty weight to be 998 pounds and an empty weight cg of 13.48 inches. what is the new empty weight cg?
a 13.96 inches.
b 14.28 inches.
c 12.73 inches.

Explanation:

Step1: Calculate the weight change

The weight change $\Delta W=185 - 175=10$ pounds.

Step2: Calculate the moment change

The moment change $\Delta M=\Delta W\times(- 62)$ (since the station is - 62.00 inches). So $\Delta M = 10\times(-62)=-620$ inch - pounds.

Step3: Calculate the new empty weight

The new empty weight $W_{new}=998 + 10=1008$ pounds.

Step4: Calculate the original moment

The original moment $M_{old}=998\times13.48 = 998\times(13 + 0.48)=998\times13+998\times0.48=12974+479.04 = 13453.04$ inch - pounds.

Step5: Calculate the new moment

The new moment $M_{new}=M_{old}+\Delta M=13453.04-620 = 12833.04$ inch - pounds.

Step6: Calculate the new empty - weight CG

The new empty - weight $CG=\frac{M_{new}}{W_{new}}=\frac{12833.04}{1008}=12.73$ inches.

Answer:

C. 12.73 Inches.