ACS Weight & Balance 2 — Questions and Answers
Question 1: An aircraft's empty weight CG is at 82.5 inches aft of datum. If the maximum forward CG limit is 78.0 inches and maximum aft CG limit is 86.5 inches, is the empty weight CG within limits?
- Yes, 82.5 is between 78.0 and 86.5 (Correct answer)
- No, 82.5 exceeds the aft limit
- Yes, but only if the aircraft is loaded to MTOW
- No, empty weight CG is always out of limits
Correct answer: Yes, 82.5 is between 78.0 and 86.5
82.5 inches falls between the forward limit of 78.0 and the aft limit of 86.5 inches, so the empty weight CG is within limits.
Question 2: What is the primary purpose of ballast in an aircraft weight and balance context?
- To increase gross weight capacity
- To shift the CG to within approved limits (Correct answer)
- To reduce fuel consumption
- To increase structural load capacity
Correct answer: To shift the CG to within approved limits
Ballast is temporary or permanent weight added to move the aircraft CG into the approved operating range.
Question 3: An aircraft has a moment of 186,000 in-lb and a weight of 2,400 lb. What is the CG location?
- 77.5 inches (Correct answer)
- 78.5 inches
- 75.0 inches
- 80.0 inches
Correct answer: 77.5 inches
CG = Moment ÷ Weight = 186,000 ÷ 2,400 = 77.5 inches.
Question 4: Which of the following items is typically included in the basic empty weight of an aircraft?
- Pilot and passengers
- Usable fuel
- Unusable fuel and full operating fluids (Correct answer)
- Removable ballast
Correct answer: Unusable fuel and full operating fluids
Basic empty weight includes the airframe, engine, fixed equipment, unusable fuel, and full operating fluids (oil, hydraulic fluid).
Question 5: When computing weight and balance, a negative moment indicates the weight is located:
- Forward of the datum (Correct answer)
- Aft of the datum
- At the datum
- Above the center of gravity
Correct answer: Forward of the datum
A negative arm (forward of datum) multiplied by a positive weight produces a negative moment, indicating weight forward of the datum.
Question 6: What effect does moving the datum location aft have on arm values throughout the aircraft?
- All arms become longer (more positive)
- All arms become shorter or more negative (Correct answer)
- Arms remain unchanged
- Only forward arms are affected
Correct answer: All arms become shorter or more negative
Moving the datum aft reduces or makes more negative the arm of every station, since arm = station distance from datum.
Question 7: An aircraft certificated under FAR Part 23 must have weight and balance data that includes:
- Only the basic empty weight
- Empty weight, empty weight CG, and useful load (Correct answer)
- Gross weight and fuel capacity only
- Maximum ramp weight only
Correct answer: Empty weight, empty weight CG, and useful load
FAR Part 23 requires the aircraft flight manual to include empty weight, empty weight CG location, and useful load information.
ACS Weight & Balance 2
An aircraft's empty weight CG is at 82.5 inches aft of datum.
If the maximum forward CG limit is 78.0 inches and maximum aft CG limit is 86.5 inches, is the empty weight CG within limits?