Appendix 1
k. Drainable unusable fuel;
l. Spare parts normally carried aboard and not accounted for as cargo; and
m. All other equipment considered standard by the operator.
23. Passenger assist/comfort animals and devices. These include, but are not limited to, canes, crutches, walkers, wheelchairs, medically-required animal comfort companions, or animals required to assist the vision impaired.
24. Passenger weight. Passenger weight is the actual weight or the approved average weight of the passenger.
a. An adult is defined as an individual 13 years or older.
b. A child is defined as an individual aged 2 to less than 13 years of age.
c. Infants are children who have not yet reached their second birthday and are considered part of the adult standard average and segmented passenger weight.
25. Personal item. Items the operator may allow a passenger to carry aboard, in addition to a carry-on bag. Typically, an operator may allow one personal item such as a purse, briefcase, computer and case, camera and case, diaper bag, or an item of similar size. Other items, such as coats, umbrellas, reading material, food for immediate consumption, infant restraining device, and passenger assist/comfort animals and devices, are allowed to be carried on the aircraft and are not counted against the personal item allowance.
26. Plane-side loaded bag. Any bag or item that is placed at the door or steps of an aircraft and subsequently placed in the aircraft cargo compartment or cargo bin.
27. Reference Balance Arm (BA). The horizontal distance from the reference datum to the CG of an item.
28. Segmented Weights. Passenger weights derived by adding a portion of the standard deviation to an average weight to increase the confidence that the actual weight will not exceed the average weight.
29. Small cabin aircraft. Aircraft with a maximum type-certificated seating capacity between 5 and 29 passenger seats, inclusive.
30. Standard basic empty weight. Manufacturer’s empty weight plus standard items.
31. Standard items. Equipment and fluids not considered an integral part of a particular aircraft and not a variation for the same type of aircraft. These items may include, but are not limited to, the following:
a. Unusable fuel and other unusable fluids;
b. Engine oil;
Appendix 1
c. Toilet fluid and chemical;
d. Fire extinguishers, pyrotechnics, and emergency oxygen equipment;
e. Structure in galley, buffet, and bar; and
f. Supplementary electronic equipment.
32. Useful Load. Difference between takeoff weight and OEW. It includes payload, usable fuel, and other usable fluids not included as operational items.
Appendix 2 APPENDIX 2. SOURCE OF STANDARD AVERAGE WEIGHTS IN THIS AC
1. Standard average passenger weights.
a. The Federal Aviation Administration (FAA) examined data from several large-scale, national health studies conducted by U.S. Government health agencies. The FAA found that the National Health and Nutrition Examination Survey (NHANES), conducted by the Centers for Disease Control (CDC), provided the most comprehensive and appropriate data. The data in NHANES cover a broad spectrum of the general population, are based on a large sample size, and are not restricted geographically to a particular area.
b. The CDC collects NHANES data annually by conducting an actual scale weighing of approximately 9,000 subjects in a clinical setting. The standard deviation of the sample was 47 pounds. The CDC last published results from NHANES in 2000. Additional information on NHANES can be found at the following Web sites:
(1) General information.
http://www.cdc.gov/nchs/nhanes.htm
(2) Analytic and reporting guidelines.
http://www.cdc.gov/nchs/data/nhanes/nhanes3/nh3gui.pdf
(3) Data files for 1999–2000 survey.
http://www.cdc.gov/nchs/about/major/nhanes/NHANES99_00.htm
c. The FAA used most recent NHANES data set from surveys conducted in 1999 and 2000 to calculate the standard average passenger weights used in this advisory circular (AC). From this data set, the FAA separated out a separate data set of individuals who had not yet reached their 13th birthday to determine average child weight. From the remaining adult data set, the FAA removed all weight data that indicated the subject was clothed during the weighing and removed all data points more than two standard deviations from the mean. The FAA then calculated the average weights for males and females in the remaining data set.
2. Standard average bag weights.
To determine standard average weights for different types of bags, the FAA closely examined previous surveys conducted by operators, including several surveys conducted in response to FAA Notice 8400.40, Weight and Balance Control Programs for 10 to 19 Seat Airplanes Operated Under 14 CFR 121. The results of those surveys are summarized in Table 2-1.
TABLE 2-1. BAG SURVEY RESULTS Item Surveyed Average Weight Standard Deviation Personal items and carry-on bags
15.1 lb 8.2 lb Checked bags 28.9 lb 10.8 lb Heavy bags 58.7 lb 7.2 lb Page 1 (and 2)
Appendix 3 APPENDIX 3. SAMPLE OPERATIONAL LOADING ENVELOPE
1. Introduction.
The following is an example of how to develop an operational loading envelope. For this example, a hypothetical 19-seat commuter category aircraft is used. Although this example uses inches to measure fuselage station, an operator may choose to use an index system for convenience.
2. Assumptions for this example.
a. Passenger weight. Because the aircraft is certificated under the commuter category of Title 14 of the Code of Federal Regulations (14 CFR) part 23 and because it is originally typecertificated for 5 or more passenger seats, it would be appropriate to use the average weights listed in Chapter 3, Section 2. For this example, it is assumed that the operator does not have a carry-on bag program. Therefore, the operator should use a standard average passenger weight of 189 pounds in winter and 184 pounds in summer. For this example, a standard average passenger weight of 189 pounds is used. The operator also assumes that passengers are distributed throughout the cabin in accordance with the window-aisle-remaining method. Note that because this aircraft has only two window seats per row, the operator may reasonably assume that passengers begin seating themselves in the front of the cabin and select the most forward seat available.
b. Bag weights. For this example, the operator assumes that a checked bag weighs 30 pounds and a plane-side loaded bag weighs 20 pounds.
c. Interior seating. For this example, consider a commuter category 19-seat aircraft with the interior seating diagram shown in Figure 3-1.
FIGURE 3-1. SAMPLE AIRCRAFT INTERIOR SEATING DIAGRAM (Diagram courtesy of Raytheon Aircraft Company) Page 1
Appendix 3
3. Curtailments for passenger seating variation.
a. Establishing zones. The operator elects to separate the passenger cabin into three zones.
Zone 1 will contain rows 1 to 3, zone 2 will contain rows 4 to 6, and zone 3 will contain rows 7 to 9.
b. Determining the centroid of each zone. When using cabin zones, an operator assumes that all passengers are sitting at the centroid of their zone. To find the centroid of each zone—
(1) Multiply the number of seats in each row of the zone by the location of the row,
(2) Add each number calculated in step 1, and
(3) Divide the number in step 2 by the total number of seats in the zone.
NOTE: For this sample aircraft, see Tables 3-1 through 3-3 below.
TABLE 3-1. CALCULATION OF ZONE 1 CENTROID Row No. No. of Seats Row Location No. of Seats × Row Location 1 2 198 in 396 in 2 2 228 in 456 in 3 2 258 in 516 in TOTAL 6 NA 1,368 in 1,368 in / 6 seats = 228 in
TABLE 3-2. CALCULATION OF ZONE 2 CENTROID Row No. No. of Seats Row Location No. of Seats × Row Location 4 2 289 in 578 in 5 2 318 in 636 in 6 2 347 in 694 in TOTAL 6 NA 1,908 in 1,908 in / 6 seats = 318 in
TABLE 3-3. CALCULATION OF ZONE 3 CENTROID Row No. No. of Seats Row Location No. of Seats × Row Location 7 2 377 in 754 in 8 2 407 in 814 in 9 3 436 in 1,308 in TOTAL 7 NA 2,876 in 2,876 in / 7 seats = 411 in Page 2
Appendix 3
c. Comparing loading assumptions. To determine the appropriate amount of curtailment, the operator should compare aircraft loading based on the window-aisle-remaining assumption with aircraft loaded based on the assumption that passengers are sitting at the centroid of their respective zones. An operator may determine the appropriate curtailment by comparing the moments resulting from these assumptions and identifying the loading scenarios that result in the most forward or aft center of gravity (CG) location. See Tables 3-4 through 3-12 below.
(1) Curtailment calculation for zone 1.
TABLE 3-4. MOMENTS RESULTING FROM THE ZONE CENTROID ASSUMPTION FOR ZONE 1 Passenger No.
Assumed Weight Assumed Arm Moment Cumulative Moment 1 189 lb 228 in 43,092 in-lb 43,092 in-lb 2 189 lb 228 in 43,092 in-lb 86,184 in-lb 3 189 lb 228 in 43,092 in-lb 129,276 in-lb 4 189 lb 228 in 43,092 in-lb 172,368 in-lb 5 189 lb 228 in 43,092 in-lb 215,460 in-lb 6 189 lb 228 in 43,092 in-lb 258,552 in-lb
TABLE 3-5. MOMENTS RESULTING FROM THE WINDOW-AISLE-REMAINING ASSUMPTION FOR ZONE 1 Passenger No.
Assumed Row Weight Arm Moment Cumulative Moment 1 1 189 lb 198 in 37,422 in-lb 37,422 in-lb 2 1 189 lb 198 in 37,422 in-lb 74,844 in-lb 3 2 189 lb 228 in 43,092 in-lb 117,936 in-lb 4 2 189 lb 228 in 43,092 in-lb 161,028 in-lb 5 3 189 lb 258 in 48,762 in-lb 209,790 in-lb 6 3 189 lb 258 in 48,762 in-lb 258,552 in-lb
TABLE 3-6. COMPARISON OF MOMENTS FOR ZONE 1 Passenger No.
Cumulative Moment From the Zone Centroid Assumption Cumulative Moment From the Window-Aisle-Remaining Assumption Difference 1 43,092 in-lb 37,422 in-lb -5,670 in-lb 2 86,184 in-lb 74,844 in-lb -11,340 in-lb 3 129,276 in-lb 117,936 in-lb -11,340 in-lb 4 172,368 in-lb 161,028 in-lb -11,340 in-lb 5 215,460 in-lb 209,790 in-lb -5,670 in-lb 6 258,552 in-lb 258,552 in-lb 0 in-lb Page 3
Appendix 3
(2) Curtailment calculation for zone 2.
TABLE 3-7. MOMENTS RESULTING FROM THE ZONE CENTROID ASSUMPTION FOR ZONE 2 Passenger No.
Assumed Weight Assumed Arm Moment Cumulative Moment 7 189 lb 318 in 60,102 in-lb 60,102 in-lb 8 189 lb 318 in 60,102 in-lb 120,204 in-lb 9 189 lb 318 in 60,102 in-lb 180,306 in-lb 10 189 lb 318 in 60,102 in-lb 240,408 in-lb 11 189 lb 318 in 60,102 in-lb 300,510 in-lb 12 189 lb 318 in 60,102 in-lb 360,612 in-lb
TABLE 3-8. MOMENTS RESULTING FROM THE WINDOW-AISLE-REMAINING ASSUMPTION FOR ZONE 2 Passenger No.
Assumed Row Weight Arm Moment Cumulative Moment 7 4 189 lb 289 in 54,621 in-lb 54,621 in-lb 8 4 189 lb 289 in 54,621 in-lb 109,242 in-lb 9 5 189 lb 318 in 60,102 in-lb 169,344 in-lb 10 5 189 lb 318 in 60,102 in-lb 229,446 in-lb 11 6 189 lb 347 in 65,583 in-lb 295,029 in-lb 12 6 189 lb 347 in 65,583 in-lb 360,612 in-lb
TABLE 3-9. COMPARISON OF MOMENTS FOR ZONE 2 Passenger No.
Cumulative Moment From the Zone Centroid Assumption Cumulative Moment From the Window-Aisle-Remaining Assumption Difference 7 60,102 in-lb 54,621 in-lb -5,481 in-lb 8 120,204 in-lb 109,242 in-lb -10,962 in-lb 9 180,306 in-lb 169,344 in-lb -10,962 in-lb 10 240,408 in-lb 229,446 in-lb -10,962 in-lb 11 300,510 in-lb 295,029 in-lb -5,481 in-lb 12 360,612 in-lb 360,612 in-lb 0 in-lb Page 4
Appendix 3
(3) Curtailment calculation for zone 3.
TABLE 3-10. MOMENTS RESULTING FROM THE ZONE CENTROID ASSUMPTION FOR ZONE 3 Passenger No.
Assumed Weight Assumed Arm Moment Cumulative Moment 13 189 lb 411 in 77,679 in-lb 77,679 in-lb 14 189 lb 411 in 77,679 in-lb 155,358 in-lb 15 189 lb 411 in 77,679 in-lb 233,037 in-lb 16 189 lb 411 in 77,679 in-lb 310,716 in-lb 17 189 lb 411 in 77,679 in-lb 388,395 in-lb 18 189 lb 411 in 77,679 in-lb 466,074 in-lb 19 189 lb 411 in 77,679 in-lb 543,753 in-lb
TABLE 3-11. MOMENTS RESULTING FROM THE WINDOW-AISLE-REMAINING ASSUMPTION FOR ZONE 3 Passenger No.
Assumed Row Weight Arm Moment Cumulative Moment 13 7 189 lb 377 in 71,253 in-lb 71,253 in-lb 14 7 189 lb 377 in 71,253 in-lb 142,506 in-lb 15 8 189 lb 407 in 76,923 in-lb 219,429 in-lb 16 8 189 lb 407 in 76,923 in-lb 296,352 in-lb 17 9 189 lb 436 in 82,404 in-lb 378,756 in-lb 18 9 189 lb 436 in 82,404 in-lb 461,160 in-lb 19 9 189 lb 436 in 82,404 in-lb 543,564 in-lb
TABLE 3-12. COMPARISON OF MOMENTS FOR ZONE 3 Passenger No.
Cumulative Moment From the Zone Centroid Assumption Cumulative Moment From the Window-Aisle-Remaining Assumption Difference 13 77,679 in-lb 71,253 in-lb -6,426 in-lb 14 155,358 in-lb 142,506 in-lb -12,852 in-lb 15 233,037 in-lb 219,429 in-lb -13,608 in-lb 16 310,716 in-lb 296,352 in-lb -14,364 in-lb 17 388,395 in-lb 378,756 in-lb -9,639 in-lb 18 466,074 in-lb 461,160 in-lb -4,914 in-lb 19 543,753 in-lb 543,564 in-lb -189 in-lb Page 5
Appendix 3
(4) Determining the most adverse loading. It is important that an operator examine the above results for each zone and determine which loading scenario results in the greatest difference in moments. For zones 1 and 2, having two, three, or four passengers in the zone results in the largest difference between the moments. For zone 3, having four passengers in the zone results in the largest difference. In this case, the operator should curtail the manufacturer’s loading envelope forward and aft by the sum of these moments, 36,666 inch-pounds, to account for the potential variation in passenger seating. In this example, the 36,666 inch-pounds is the sum of 11,340 from Table 3-6; 10,962 from Table 3-9; and 14,364 from Table 3-12.
(5) Using actual seating location. Alternatively, an operator may reasonably avoid the above curtailment calculations by determining the actual seating location of each passenger in the cabin. By eliminating potential variation in passenger seating, an operator would not need to make assumptions about passenger seating and would not need to curtail the loading envelope accordingly. An operator choosing to use actual seating location should have procedures in place to ensure that passengers sit in their assigned location.
4. Other curtailments to the manufacturer’s loading envelope.
a. Variation in passenger weight. Because the operator in this example elects to use standard average weights on a small-cabin aircraft, an additional curtailment for potential variation in passenger weight is required. The operator should curtail the manufacturer’s loading envelope by 23,791 inch-pounds forward and aft to account for the variation in passenger weight.
A full explanation of this calculation is contained in Appendix 4.
b. Variation in fuel density. Because the loading of fuel does not significantly change the CG of the aircraft, the operator would not need to provide a curtailment for variation in fuel density.
c. Fuel movement in flight. For this sample aircraft, the manufacturer has considered the movement of fuel in flight. Therefore, the operator does not need to include additional curtailments in the operational loading envelope.
d. Fluids. The sample aircraft does not have a lavatory or catering.
e. Bags and freight. The sample aircraft has an aft bag compartment split into two sections.
If the operator has procedures in place to restrict the movement of bags between the two sections, no additional curtailment to the envelope is required.
f. In-flight movement of passengers and crewmembers. Because there are no flight attendants and the aircraft is not equipped with a lavatory, it is reasonable to assume that passengers or crewmembers will not move about the cabin in flight.
g. Movement of flaps and landing gear. The manufacturer of the sample aircraft has considered the movement of flaps and landing gear in the development of its loading envelope.
The operator does not need to include any additional curtailments in its operational loading envelope for the movement of those items.
Appendix 3
h. Fuel consumption. To ensure the sample aircraft remains within the manufacturer’s CG limits as fuel is consumed, the operator should curtail the aft CG at weights less than the zero-fuel weight by 8,900 inch-pounds. In this example, the 8,900 inch-pounds is the fuel burn deviation that would bring the aircraft outside the aft CG limit during the course of flight.
5. Operational loading envelope diagrams.
a. Figure 3-2 below shows the operator’s curtailments to the manufacturer’s loading envelope, based on the assumptions made about variations in passenger seating and weight, as well as fuel consumption.
FIGURE 3-2. OPERATIONAL LOADING ENVELOPE WITH A CURTAILMENT FOR
VARIATIONS IN PASSENGER SEATING 9,000 10,000 11,000 12,000 13,000 14,000 15,000 16,000 17,000 18,000 272 276 280 284 288 292 296 300 304 Fuselage Station (Inches Aft of Datum) Weight (LBS) Max Ramp Weight Max Landing Weight Max Zero Fuel Weight Curtailment for Variations to Passenger Weight Curtailment for Fuel Burn Off Curtailment for Variations to Passenger Seating
b. To expand the operational loading envelope, an operator could choose to use the actual seating location of passengers in the cabin and eliminate the curtailment for variations in passenger seating. Figure 3-3 below shows the expansion of the operational loading envelope.
Appendix 3 FIGURE 3-3. OPERATIONAL LOADING ENVELOPE USING ACTUAL SEATING
LOCATION OF PASSENGERS 9,000 10,000 11,000 12,000 13,000 14,000 15,000 16,000 17,000 18,000 272 276 280 284 288 292 296 300 304 Fuselage Station (Inches Aft of Datum) Weight (LBS) Max Ramp Weight Max Landing Weight Max Zero Fuel Weight Curtailment for Variations to Passenger Weight Curtailment for Fuel Burn Off