Homework Exercise to prepare for Class #9. Answer these on notebook paper then correct or improve your answers (using another color) by referring to the answer sheet. 1. What is the term for the reference plane from which all horizontal measurements are made in order to determine the arm used for weight and balance calculations?. 2. How is unusable fuel defined? 3. What does basic empty weight include? a. The weight of full oil. b. The weight of minimum fuel. c. The weight of full fuel. 4. If your weight check shows that the airplane will exceed the maximum ramp weight specified in the POH, which of the following actions would be appropriate? a. Take off at that weight, but not taxi. b. Rearrange the load to bring it within CG limits. c. Remove passengers, cargo, or fuel until the weight limit is reached. 5. What is the weight of 42 gallons of aviation gasoline? a. 242 pounds. b. 248 pounds. c. 252 pounds. 6. The moment for a rear seat passenger is 14,800 inch-pounds. If this passenger sits in the front seat, will his/her moment be higher or lower? The following blank chart is one that you are going to want to memorize. Faithfully using this format on virtually all weight and balance problems will help assure that you solve the problem correctly: Empty Airplane Front Seats Back Seats Fuel Baggage TOTAL Weight Arm Moment 2011 Joseph J. Zubay 10/31/12 Page 1 of 5 Pages
7. True/False. Moment is expressed in inches. Why or why not? 8. You are planning a trip with three friends. You and your front seat passenger weigh a total of 366 pounds. The rear seat passengers each weigh 173 pounds. The suitcases and bags weigh 150 pounds total. Assume that 120 pounds of the bags will be in baggage area A and the remainder in baggage area B. Using the following graph, find the total moment so far (we haven t dealt with the fuel or empty weight yet). 9. (Contd. From question 8.) This airplane has an empty weight of 1,850 pounds, and the empty weight moment is 64,900 inch-pounds. It has a maximum allowable gross weight of 3,100 pounds, so how much usable fuel can be loaded and still remain within weight and CG limits? (Use the following moment envelope.) 2011 Joseph J. Zubay 10/31/12 Page 2 of 5 Pages
10. (Contd. From question 9.)The center of gravity of this fully loaded airplane (using all the data from question 8 and 9 above) will be how many inches from the datum? 11. If flight had been attempted without changing the load distribution in the last question, what flight characteristics could be expected? a. Tail-heaviness, requiring additional forward trim. b. Light control forces, longitudinal instability, and a higher cruise speed for the power setting used. c. All of the above. 12. Compared to a lightly loaded airplane, what flight characteristics can be expected from a heavily loaded airplane? a. It will stall at a higher speed, cruise at a slower speed, and have less range. b. It will land at a lower speed, cruise at a higher speed, and stall at a higher angle of attack. c. It will have a higher cruise speed and range, a reduced rate of climb, and stall at the same speed. 13. Select the true statement(s) regarding operating limitations: A. Operating limitations are often referred to as the flight or performance envelope. B. Operating limitations establish the boundaries within which the airplane must be flown. 2011 Joseph J. Zubay 10/31/12 Page 3 of 5 Pages
C. The FARs specify that operating limitations must be published in the approved flight manual, approved manual material, markings, and placards; or any combination of these. 14. Describe how density altitude affects aircraft performance. 15. True/False. Takeoff performance depends primarily on factors that can be measured or calculated in advance such as density altitude, pressure altitude, temperature, wind, aircraft weight, and runway gradient and surface. 16. Refer to Figure 37. Determine the headwind and crosswind components for a departure on runway 18 with a reported wind (reported by ATIS) of 210 at 20 knots. 17. What is the runway gradient? A. The material used to surface the runway. B. The amount of change in runway height over its length. C. The direction of the runway as it relates to magnetic north. 18. Name the three important factors that the pilot must consider when planning the climb segment of a flight. 19. Select the items that would be found on a cruise performance chart. A. Time, fuel, and distance to climb. B. Fuel consumption and airspeed at various power settings. C. Power required for level flight, including maximum level flight speed and L/Dmax. 20. True/False. Landing weight is not a factor that must be considered during an approach. 2011 Joseph J. Zubay 10/31/12 Page 4 of 5 Pages
ANSWERS to the Homework Exercise to prepare for Class #9. Do Not View This until all questions are answered. Use the following to correct or improve your answers. Correct or append your answers using another color pencil or pen. Do not erase incorrect answers strike them out so the incorrect data are still readable. 1. Datum or Reference Datum. 2. Fuel, which cannot be drained or safely used for flight. 3. a. 4. c. 5. c. 6. Lower. 7. False. It is expressed in inch-pounds (or sometimes pound-inches) because it is the product of multiplying two factors, the weight in pounds and the distance from the datum (arm) in inches. 8. 55,000 inch-pounds. 9. 64.76 gallons is the precise answer. The practical answer would be 65 gallons (not 64 ½ gallons). 10. 44.65 inches. 11. c. 12. a. 13. A, B, and C are true. 14. As density altitude increases, engine horsepower decreases for normally aspirated engines since the actual amount of air to support combustion has decreased. In other words, there are less oxygen molecules in every cubic inch of high density altitude air than in low density altitude air so less fuel can be burned. In addition, both the wing and the propeller lose efficiency in thinner air. 15. True. 16. Headwind = 17 knots; Crosswind = 10 knots. 17. B. 18. Time, fuel, and distance. 19. B. 20. False. 2011 Joseph J. Zubay 10/31/12 Page 5 of 5 Pages