3-1 CHAPTER 3. METHODS TO DETERMINE THE WEIGHT OF PASSENGERS
3.1 Choosing the Appropriate Method.
3.1.1 What Should an Operator Consider when Choosing the Appropriate Method?
3.1.1.1 Using Average Weights. For many years, operators of transport category aircraft have used average weights for passengers and bags to calculate an aircraft’s W&B, in accordance with standards and recommended practices.
This method eliminates many potential sources of error associated with accounting for a large number of relatively lightweights. However, differences between the actual weight of passengers and bags and the average weight of passengers and bags can occur when using average weights.
3.1.1.2 Using Standard Average Passenger Weights. Statistical probability dictates that the smaller the sample size (i.e., cabin size), the more the average of the sample will deviate from the average of the larger universe. Because of this, the use of standard average passenger weights in W&B programs for small and medium cabin aircraft should be examined in greater detail.
3.1.1.3 Determining Passenger and Bag Weight. Three methods are available to operators to determine passenger and bag weight. These methods include standard average weights, as described in paragraph 3.2; average weights based on survey results, as described in paragraph 3.3; and actual weights, as described in paragraph 3.4. An operator should review the following discussion and consult Table 3-1, Example of Standard Average Passenger Weights, to determine which methods are appropriate to its type of operation.
Operators should see paragraphs 3.3 and 3.4 for determining baggage weights.
3.1.1.4 Large Cabin Aircraft. Operators of large cabin aircraft may use the standard average weights for passengers. If an operator determines the standard average weights are not representative of its operation for certain route or regions, the operator should conduct a survey as detailed in paragraph 3.3 to establish more appropriate average weights for its operation. Operators of large cabin aircraft should conduct a baggage survey as detailed in paragraph 3.3 to establish standard average baggage weights for their operation. Large cabin operators also have the option of using actual baggage weights as described in paragraph 3.4. Operators should have procedures along with controls for identifying situations that would require the use of nonstandard weight groups or actual weights.
3.1.1.5 Medium Cabin Aircraft.
3.1.1.5.1 Evaluation Criteria for Medium Cabin Aircraft. Operators should evaluate medium cabin aircraft to determine whether to treat the aircraft as a large or small cabin aircraft. For the FAA to recommend that medium cabin aircraft be treated as a large cabin aircraft, the aircraft must meet either:
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1. Loadability criteria, or
2. The loading schedule criteria.
3.1.1.5.2 Evaluation Criteria for Small Cabin Aircraft. If the aircraft does not meet either the loadability or loading schedule criteria, then the FAA does not recommend that the operator use large cabin aircraft procedures. Instead, the aircraft should be subject to the small cabin aircraft methods outlined in paragraph 3.1.1.6.
3.1.1.5.3 Loadability Criteria.
• The center of gravity (CG) of the Basic Empty Weight (BEW) is within the manufacturer’s loading envelope.
• The CG of the zero fuel weight is within the manufacturer’s loading envelope when loaded with a full load of passengers and all cargo compartments are filled with a density of 10 pounds per cubic foot.
3.1.1.5.4 Loading Schedule Criteria.
• The operator must use a loading schedule based upon zones.
• The aircraft cabin may have no more than four rows of seats per zone with not less than four zones.
3.1.1.6 Small Cabin Aircraft. Operators of small cabin aircraft may request approval to use any one of the following methods when calculating the aircraft W&B.
1. Actual passenger and bag weights, or
2. Standard average passenger and standard average by surveying bag weights prescribed for large cabin aircraft or average weights based on an FAA-accepted survey if:
• The aircraft was certificated under part 23 normal category, part 25, or part 29 (or is able to prove the aircraft has equivalent part 23 normal category or part 29 performance data); and
• When using the Window-Aisle-Remaining (Zone) Method, the operator applies the additional curtailments as prescribed in Appendix D, Additional Curtailment to CG Envelopes for Passenger Weight Variations in Small Cabin Aircraft.
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3.2 Standard Average Weights.
3.2.1 What Standard Average Passenger Weights Should an Operator Use?
3.2.1.1 The standard average passenger weights are based on data from U.S. Government health agency surveys. An operator may use the example table in Table 3-1 in association with the Centers for Disease Control (CDC) weights to establish their standard average weights. The first column in Table 3-1 are CDC/National Health and Nutrition Examination Survey (NHANES) weights without summer or winter clothing weights. For more background information on the source of these weights, refer to Appendix B, Source of Standard Average Weights.
3.2.1.2 The operator will use the third column labeled “Standard Average Weight” in Table 3-1 to enter in their standard average weight per passenger based on seasonal clothing variance. The standard average weight is calculated by adding the CDC/NHANES weights in the first column and the clothing weights located the middle column. The clothing weights are 5 pounds for summer clothing, and 10 pounds for winter clothing. Where no gender is given, the standard average passenger weights are based on the assumption that 50 percent of passengers are male and 50 percent of passengers are female.
Table 3-1. Example of Standard Average Passenger Weights
CDC/NHANES Weights Average Clothing Weight Standard Average Weight Summer Weights Summer Weights lbs Average passenger weight (5 lbs) lbs lbs Average male passenger weight (5 lbs) lbs lbs Average female passenger weight (5 lbs) lbs lbs Child weight (2 years to less than 13 years of age) (5 lbs) lbs
Winter Weights Winter Weights lbs Average passenger weight (10 lbs) lbs lbs Average male passenger weight (10 lbs) lbs lbs Average female passenger weight (10 lbs) lbs lbs Child weight (2 years to less than 13 years of age) (10 lbs) lbs
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3.2.1.3 An operator may use summer weights from May 1 to October 31, and winter weights from November 1 to April 30. However, these dates may not be appropriate for all routes or operators. For routes with no seasonal variation, an operator may use the average weights appropriate to the climate. Use of year-round average weights for operators with seasonal variation should avoid using an average weight that falls between the summer and winter average weights. Operators with seasonal variation that elect to use a year-round average weight should use the winter average weight. The FAA must approve use of seasonal dates, other than those listed above.
3.2.1.4 The standard average weights listed in Table 3-1 will not take into consideration a carry-on bag program. Operators should see paragraphs 3.3 and 3.4 for baggage weights.
Note: The weight of children under the age of 2 must be accounted for by using the current edition of CDC Anthropometric Reference Data for Children and Adults. The carrier may either: 1) use the mean of both male and female weights under the age of 2; or 2) provide the Administrator with survey data to support how many children under the age of 2 should be calculated along with the adult passenger weights.
3.2.1.5 The standard average passenger weights established by the operator will be provided to the FAA for review and approval, and entered into the operator’s operations specifications (OpSpecs), management specifications (MSpecs), or Letter of Authorization (LOA), as applicable.
3.2.2 What Are the Standard Average Weights for Crewmembers?
3.2.2.1 An operator may choose to use one of the following for crewmember weights:
CDC/NHANES weights for F/As and Civil Aerospace Medical Institute (CAMI) first- and second-class medical certificate weights to establish their standard crewmember weights. The operator also has the option to conduct a survey as described in paragraph 3.3, or use actual weights as described in paragraph 3.4 to establish average crewmember weights appropriate for its operation.
3-5 Table 3-2. Standard Crewmember Weights Crewmember CAMI Medical Certificate Average Weights CDC/ NHANES Average Weight Uniform Weights Crewmember Average Weights with Uniform Crewmember Average Weight with Uniform & Bags Male flightcrew member lbs lbs lbs lbs lbs Female flightcrew member lbs lbs lbs lbs lbs Flight attendant NA lbs lbs lbs lbs Male flight attendant NA lbs lbs lbs lbs Female flight attendant NA lbs lbs lbs lbs Crewmember Bag Weights
Crewmember roller bag lbs Pilot flight bag lbs Flight attendant kit lbs
3.2.2.2 The operator should use Table 3-2, Standard Crewmember Weights to establish their standard crewmember weights. The operator must either use survey weights or actual weights for crewmember uniforms, bags, pilot flight bags, and F/A kit(s) as described in paragraphs 3.3 and 3.4. The operator will add CDC/NHANES weights to the table as described in paragraph 3.2.1, and Appendix B.
3.2.2.3 If the operator opts to use first- and second-class medical weights provided by CAMI, the operator must use the most current Aerospace Medical Certification Statistical Handbook report. The first-and second-class medical mean weight from the report should be placed in the second column titled “CAMI Medical Certificate Average Weights” of Table 3-2. (For additional information on CAMI, see Appendix B.)
3.2.2.4 The F/A weights with bags assume that each F/A has one crewmember roller bag and one F/A kit.
3.2.2.5 An operator may include the weight of crewmembers in an aircraft’s BEW or add the weight to the load manifest prepared for each flight.
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3.2.2.6 The standard average crewmember weights established by the operator will be provided to the FAA for review and approval and issued through the operator’s OpSpecs, MSpecs, or LOA, as applicable.
3.2.3 What Weights May Be Used for Company Materials (COMAT), Freight, and Mail?
3.2.3.1 COMAT and Freight. An operator should use actual weights for company materials, aircraft parts, and freight carried aboard an aircraft.
3.2.3.2 Mail. An operator should use the weights provided with manifested mail shipments to account for the weight of the mail. If an operator has to separate a shipment of mail, the operator may make actual estimates about the weight of the individual pieces, provided the sum of the estimated weights is equal to the actual manifested weight of the entire shipment.
Note: Operators must ensure when using manifested mail shipments to account for weight, the operator must have procedures to ensure the weights provided are verified.
3.2.4 What are the Standard Average Weights for Special Passenger Groups that Do Not Fit an Operator’s Standard Average Weight Profile?
3.2.4.1 Actual passenger weights should be used for nonstandard weight groups
(e.g., sports teams) unless average weights have been established for such groups by conducting a survey in accordance with the procedures established in paragraph 3.1. When such groups form only a part of the total passenger load, actual weights, or established average weights for the nonstandard group, should be used for such exception groups and average weights used for the balance of the passenger load. In such instances, a notation should be made in the load manifest indicating the number of persons in the special group and identifying the group (e.g., football squad).
3.2.4.2 Roster weights may be used for determining the actual passenger weight.
3.2.4.3 Actual baggage weights must be used in cases where the carry-on bags are not representative of the operator’s profile.
3.2.4.4 Groups that are predominantly male or female should use the standard average weights for males or females provided in Table 3-1.
3.2.4.5 For military groups, the Department of Defense (DOD) requires actual passenger and cargo weights be used in computing the aircraft W&B for all DOD charter missions. This requirement is specified in DOD Commercial Air Carrier Quality and Safety requirements (refer to Title 32 of the Code of Federal Regulations part 861, § 861.4(e)(3)(ix)). FAA-approved air carrier W&B control programs may be used to account for carry-on/personal items for mixed loads of military and their dependents (such as channel missions).
For combat-equipped troop charters, the Air Mobility Command (AMC) will
3-7 provide guidance to account for the additional weight. If aircraft operators perceive that the weights provided are understated, they should seek confirmation of the actual weights and should make reasonable upward estimations and adjustments to those passenger and/or bag weights.
3.3 Average Weights Based on Survey Results.
3.3.1 What Should an Operator Consider when Designing a Survey?
3.3.1.1 This paragraph provides operators with an acceptable survey method to use in determining average weights for a W&B control program. This paragraph also describes how an operator can conduct a survey to count personal items, carry-on bags, and checked bags to determine an appropriate allowance for those items. In addition, an operator may use the methods described in this paragraph to conduct a survey to determine the percentage of male and female passengers and to calculate an average passenger weight.
3.3.1.2 Surveys conducted correctly allow an operator to draw reliable inferences about large populations based on relatively small sample sizes. In designing a survey, an operator should consider:
1. The sample size required to achieve the desired reliability,
2. The sample selection process, and
3. The type of survey (average weights or a count of items).
3.3.2 What Sample Sizes Should an Operator Use? Several factors must be considered when determining an adequate sample size. The more varied the population, the larger the sample size required to obtain a reliable estimate. Paragraph 3.3.3 provides a formula to derive the absolute minimum sample size to achieve a 95 percent confidence level.
Table 3-3, Minimum Sample Sizes, has been provided for those operators that wish to use calculations other than those listed in paragraph 3.3.3. Table 3-3 provides the operator with an acceptable number of samples that may be collected to obtain a 95 percent confidence level and lists the tolerable error associated with each category.
Table 3-3. Minimum Sample Sizes Survey Subject Minimum Sample Size Tolerable Error Adult (standard adult/male/female) 2,700 1% Child 1,400 2% Checked bags 1,400 2% Heavy bag 1,400 2% Planeside loaded bags 1,400 2% Personal items and carry-on bags 1,400 2% Personal items only (for operators with a no carry-on bag program) 1,400 2%
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3.3.3 When Conducting a Survey, Can an Operator Collect a Smaller Sample Size than That Published in Table 3-3? If the operator has chosen to use a sample size that is smaller than that provided in Table 3-3, the operator should collect a sufficient number of samples to satisfy the following formulas:
3.3.4 What Sampling Method Should an Operator Use?
3.3.4.1 Random Sampling. An operator conducting a survey must employ random sampling techniques. Random sampling means that every member of a group has an equal chance of being selected for inclusion in the sample. If an operator conducts a survey that does not employ random sampling, the characteristics of the selected sample may not be indicative of the larger group as a whole. Because of this, any conclusions drawn from such a survey may not be valid.
3.3.4.2 Random Sampling Methods. The following are two examples of random sampling methods that an operator may find appropriate for the type of survey conducted. An operator may also consult a basic publication on statistics to determine whether a different random sampling method is more appropriate.
3.3.4.2.1 Simple Random Selection. An operator should assign a sequential number to each item in a group (such as passengers waiting on a line or bag claim tickets). Then the operator randomly selects numbers and includes the item corresponding with the number in the sample. The operator repeats this process until it has obtained the minimum sample size.
3.3.4.2.2 Systematic Random Selection. An operator should randomly select an item in sequence to begin the process of obtaining samples. The operator should then use a predetermined, systematic process to select the remaining samples
3-9 following the first sample. For example, an operator selects the third person in line to participate in the survey. The operator then selects every fifth person after that to participate in the survey. The operator continues selecting items to include in the sample until it has obtained the minimum sample size.
3.3.4.3 Elective Passenger Participation. Regardless of the sampling method used, an operator has the option of surveying each passenger and bag aboard the aircraft and should give a passenger the right to decline to participate in any passenger or bag weight survey. If a passenger declines to participate, the operator should select the next passenger based on the operator’s random selection method rather than select the next passenger in a line. If a passenger declines to participate, an operator should not attempt to estimate data for inclusion in the survey.
3.3.5 What Should an Operator Consider when Developing a Survey Plan and Submitting it to the FAA?
3.3.5.1 Developing a Survey Plan. Before conducting a survey, an operator should develop a survey plan. The plan should describe the dates, times, and locations the survey will take place. In developing a survey plan, the operator should consider its type of operation, hours of operation, markets served, passenger mix, and frequency of flights on particular routes. In general, an operator should avoid conducting surveys on holidays or other dates that are not representative of normal operations.
3.3.5.2 Submitting the Survey Plan to the FAA. An operator should submit its survey plan to the FAA at least 30 calendar-days before the operator expects to begin the survey. Before the survey begins, the operator’s principal inspector (PI) will review the plan and work with the operator to develop a mutually acceptable plan. During the survey, the PI will oversee the survey process to validate the execution of the survey plan. After the survey is complete, the PI will review the survey results and issue the appropriate OpSpecs or MSpecs. Once a survey begins, the operator should continue the survey until complete, even if the initial survey data indicates that the average weights are lighter or heavier than expected.
3.3.6 What General Survey Procedures Should an Operator Use?
3.3.6.1 Survey Locations. An operator should accomplish a survey at one or more airports that represent at least 15 percent of an operator’s daily departures. To provide connecting passengers with an equal chance of being selected in the survey, an operator should conduct its survey within the secure area of the airport. An operator should select locations to conduct its survey that would provide a sample that is random and representative of its operations. For example, an operator should not conduct a survey at a gate used by shuttle operations unless the operator is conducting a survey specific to that route or the operator only conducts shuttle operations.
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3.3.6.2 Weighing Passengers. An operator that chooses to weigh passengers as part of a survey should take care to protect the privacy of passengers. The scale readout should remain hidden from public view. An operator should ensure that any passenger weight data collected remains confidential.
3.3.6.3 Weighing Bags. When weighing bags, the operator should account for all items taken aboard the aircraft as well as checked-in items. In addition, the operator should ensure a proper accounting for all planeside loaded items, and have procedures on how to handle these items.
Note: The operator should ensure that all scales are certified and calibrated by the manufacturer or a certified laboratory, such as a civil department of weights and measures, or the operator may calibrate the scale under an approved calibration program. The operator should also ensure that the scale is calibrated within the manufacturer’s recommended time, or time periods, as specified in the operator’s approved calibration program.
3.3.6.4 Rounding in Survey Collection. When collecting survey data, values should be recorded to the same precision as the accuracy of the collection method, including considerations such as any calibration tolerance or estimation on analog scales. For example, when using scales calibrated to the nearest pound, it is just as incorrect to record values at the tenth of a pound as it is to round to the nearest 10 pounds.
3.3.6.5 Surveys for Particular Routes. An operator may conduct a survey for a particular route if the operator believes that the average weights on that route may differ from those in the rest of its operations. To establish a standard average passenger weight along the route, an operator may survey passengers at only one location. However, an operator should conduct surveys of personal items and bags at both the departure and arrival locations of the route, unless the operator can substantiate there is no significant difference in the weight and number of bags in either direction along the route.
3.3.7 What Information Might an Operator Gain From Conducting a Count Survey?
An operator may conduct a survey to count certain items without determining the weight of those items. For example, an operator may determine that the standard average weights for male and female passengers are appropriate for its operations, but on some routes, the passengers are predominantly male or female. In such a case, an operator should conduct a survey to determine the percentage of male and female passengers. The operator could use the results of the survey to justify a weight other than the standard weights, which assume a 50 percent male and 50 percent female mix of passengers.
3.3.8 When Should an Operator Conduct Another Survey to Revalidate the Data From an Earlier Survey? In order for survey-derived average weights to be effective, an operator’s W&B control program should include a safety risk assessment and safety management principles from Safety Management Systems (SMS). The operator’s periodic assessment
3-11 should include a method to review its underlying program that considers any survey of passengers or bags. The FAA recommends operators accomplish such a review every 36 calendar-months, as well as when the operator obtains data suggesting a possible change affecting the program. Examples of such changes include the operator changing carry-on bag or checked bag policies, charges for carry-on or checked baggage, and route changes where seasonal variances may not be appropriate. If such an assessment determines that any assumption or behavior has changed, the operator should consider providing notice of a change within 90 days of completing the safety risk assessment and submit mitigating action(s), if necessary. Mitigating actions might include making changes to the program, revalidating survey data, or updating the OpSpecs described in paragraph 4.2.2.
3.3.9 What Standard Average Weights Should an Operator Use for their Baggage Weights?
An operator will use the survey methods described above to determine their standard average baggage weight. Once the operator has completed the survey, the operator will update their OpSpecs with the appropriate weights as well as update their manuals reflecting their standard baggage weights.
3.3.9.1 If an operator chooses not to survey their bags, the operator has the option of using actual weights as described in paragraph 3.4.
3.3.10 What is a Heavy Bag? A heavy bag is considered any bag that weighs more than 50 pounds but less than 100 pounds. An operator should account for a heavy bag by using one of the following weights:
1. An average weight based on the results of a survey of heavy bags, or
2. The actual weight of the heavy bag.
3.3.11 What is a Non-Luggage/Non-Standard Bag? A non-luggage/non-standard bag is any bag that does not meet the normal criteria for luggage or a bag as described in the operator’s W&B program. Examples include golf bags, fishing equipment packages, wheelchairs, strollers in their shipping configuration, windsurfing kits, and boxed bicycles. For non-luggage/non-standard bags, operators may use any appropriate combination of actual weights and average weights based on survey results. Operators that wish to establish an average weight for a particular type of non-luggage/non-standard bag, such as a golf bag, must conduct a survey in accordance with the procedures established in this chapter.
Operators should also establish a method to calculate the effect on CG of a non-luggage/non-standard bag that may occupy more than one compartment on the aircraft.
3.3.12 Planeside Loaded and Checked Bags. Operators using their standard average survey bag weights should consider all bags not stored in the cabin as checked bags. However, operators might develop procedures for identifying bags that would typically be considered carry-on and/or planeside loaded baggage and incorporate such average weights into their approved carry-on and W&B control program. When an operator develops such procedures, the operator may use the standard average weights they determined by survey, specified for carry-on, planeside loaded, and checked baggage.
3-12 Operators conducting flights in which all passenger bags are typically loaded planeside, or all bags are carried into the cabin for further storage, should develop guidelines to inform pilots when it is appropriate to use the heavier standard average checked bag weights, heavy bag weights, or actual weights.
Note: If an operator discovers that a planeside loaded bag should have been treated as a checked bag, the operator should account for that bag at the standard average weight by survey for a checked bag.
3.4 Actual Weight Programs.
3.4.1 If the Operator Decides to Use an Actual Weight Program, How Might it Determine the Actual Weight of Passengers? An operator may determine the actual weight of passengers by:
1. Weighing each passenger on a scale before boarding the aircraft (types of weight scales and scale tolerances will be defined in the operator’s approved W&B control program); or
2. Asking each passenger his or her weight. An operator should add to this asked (volunteered) weight at least 10 pounds to account for clothing. An operator should increase this allowance for clothing on certain routes or during certain seasons, if appropriate.
Note: If an operator believes that the weight volunteered by a passenger is understated, the operator should make a reasonable estimate of the passenger’s actual weight and add 10 pounds.
3.4.2 If the Operator Decides to Use an Actual Weight Program, How Should it Determine the Actual Weights of Personal Items and Bags? To determine the actual weight of a personal item, carry-on bag, checked bag, planeside loaded bag, or a heavy bag, an operator should weigh the item on a scale.
Note: The operator should ensure that all scales are certified and calibrated by the manufacturer or a certified laboratory, such as a civil department of weights and measures, or the operator may calibrate the scale under an approved calibration program. The operator should also ensure that the scale is calibrated within the manufacturer’s recommended time, or time periods, as specified in the operator’s approved calibration program.
3.4.3 What Approach Should an Operator Use to Record Actual Weights? An operator using actual weights should record all weights used in the load calculation.