AC 120-27E

AC 120-27E

DATE: 6/10/05

ADVISORY CIRCULAR

AIRCRAFT WEIGHT

AND BALANCE CONTROL

Flight Standards Service Washington, D.C.

Initiated By: AFS-200/AFS-300

Subject: AIRCRAFT WEIGHT AND

BALANCE CONTROL Date: 6/10/05 Initiated By:

AFS-200/AFS-300 AC No: 120-27E Change:

1. What is the purpose of this advisory circular (AC)?

a. This AC provides operators with guidance on how to develop and receive approval for a weight and balance control program for aircraft operated under Title 14 of the Code of Federal Regulations (14 CFR) part 91, subpart K of part 91, and parts 121, 125, and 135.

b. This AC presents recommendations for an acceptable means, but not the only means, to develop and receive approval for a weight and balance control program, and includes guidance for using average and estimated weights in accordance with part 121, section 121.153(b) and other applicable parts of subpart K of part 91 and parts 121, 125, and 135.

NOTE: Per part 125, section 125.91(b), no person may operate an airplane in a part 125 operation unless the current empty weight and center of gravity (CG) are calculated from the values established by an actual weighing of the airplane within the preceding 36 calendar-months.

c. If an operator adopts the suggestions contained in this AC, the operator must ensure that, when appropriate, it replaces discretionary language such as “should” and “may” with mandatory language in relevant manuals, operations specifications (OpSpecs), or management specifications (MSpecs).

2. How is this AC organized?

This AC has three main chapters and six appendixes. Chapter 1 addresses aircraft weighing and loading schedules. Chapter 2 describes different methods to determine the weight of passengers and bags. Chapter 3 addresses the Federal Aviation Administration’s (FAA) role in developing and approving an operator’s weight and balance control program. Finally, Appendixes 1 through 6 contain technical information such as definitions, sources of data used in the AC, a sample loading envelope, an additional curtailment for passenger weight variation, suggestions to improve accuracy, and a checklist for operators.

3. What documents does this AC cancel?

This AC cancels AC 120-27D, Aircraft Weight and Balance Control, dated August 11, 2004.

4. What should an operator consider while reading this AC?

a. Accurately calculating an aircraft’s weight and CG before flight is essential to comply with the certification limits established for the aircraft. These limits include both weight and CG limits. By complying with these limits and operating under the procedures established by the manufacturer, an operator is able to meet the weight and balance requirements specified in the aircraft flight manual (AFM). Typically, an operator calculates takeoff weight by adding the operational empty weight (OEW) of the aircraft, the weight of the passenger, cargo payload, and the weight of fuel. The objective is to calculate the takeoff weight and CG of an aircraft as accurately as possible.

b. When using average weights for passengers and bags, the operator must be vigilant to ensure that the weight and balance control program reflects the reality of aircraft loading. The FAA will periodically review the guidance in this AC and update this AC if average weights of the traveling public should change or if regulatory requirements for carry-on bags or personal items should change. Ultimately, the operator is responsible for determining if the procedures described in this AC are appropriate for use in its type of operation.

5. Who should use this AC?

a. This document provides guidance to both passenger and cargo operators that are either required to have an approved weight and balance control program under parts 121 and 125, or choose to use actual or average aircraft, passenger, or baggage weights when operating under part 91, subpart K of part 91, or part 135. The guidance in this AC is useful for anyone involved in developing or implementing a weight and balance control program.

b. As shown in Table 1, the FAA has divided aircraft into three categories for this AC to provide guidance appropriate to the size of the aircraft.

TABLE 1. AIRCRAFT CABIN SIZE For this AC, an aircraft originally type-certificated with— Is considered— 71 or more passenger seats A large-cabin aircraft.

30 to 70 passenger seats A medium-cabin aircraft.

5 to 29 passenger seats A small-cabin aircraft.

NOTE: Aircraft with fewer than five passenger seats must use actual passenger and baggage weights.

6. Who can use standard average or segmented weights?

a. Standard Average Weights. Use of standard average weights is limited to operators of multiengine turbine-powered aircraft originally type-certificated for five or more passenger seats Page ii

who hold a letter of authorization (LOA), OpSpecs, or MSpecs, as applicable, and were certificated under 14 CFR part 25, 29, or part 23 commuter category or the operator and manufacturer is able to prove that the aircraft can meet the performance requirements prescribed by part 23 commuter category aircraft. Single-engine and multiengine turbine Emergency Medical Service Helicopter (EMS/H) operators may use standard average weights for EMS operations, provided they have received an LOA.

b. Segmented Weights. Segmented weights are provided for, but not limited to those aircraft that are multiengine turbine-powered aircraft originally type-certificated for five or more passenger seats and that do not meet the performance requirements of part 23 commuter category aircraft or part 29. Segmented passenger weights are listed in Chapter 2, Table 2-5.

c. The FAA’s recommendations and advice on the safe use of standard average weights and segmented weights are contained in this document. In the FAA’s view, it would be unsafe for an aircraft operator to use standard average weights or segmented weights in any of the following aircraft:

(1) All single-engine piston-powered aircraft.

(2) All multiengine piston-powered aircraft.

(3) All turbine-powered single-engine aircraft.

NOTE: All multiengine turbine-powered aircraft certificated under part 23, except for commuter category aircraft, may only use an actual weight or segmented weight program. Operators that elect to use a segmented weight program must meet the requirements in paragraph 6b and curtail the CG envelope as specified in Appendix 3, 4, and 5. Commuter category aircraft may use standard average weights and should refer to paragraph 200f for further guidance.

7. When will the FAA revise the standard average weights in this AC?

The FAA will periodically review the standard average passenger weights listed in this AC, after the release of a new National Health and Nutrition Examination Survey (NHANES). (For information on NHANES, see Appendix 2.) If the FAA finds that the data from NHANES indicates a weight change of more than 2 percent, the FAA will revise this AC to update the standard average weights.

/s/ John M. Allen for James J. Ballough Director, Flight Standards Service

Page iii

[THIS PAGE INTENTIONALLY LEFT BLANK]

Page iv

TABLE OF CONTENTS Paragraph Page

CHAPTER 1. AIRCRAFT WEIGHTS AND LOADING SCHEDULES1

Section 1. Establishing Aircraft Weight1

100. How does an operator establish the initial weight of an aircraft?1

101. How does an operator document changes to an aircraft’s weight and balance?1

Table 1-1. Incremental Weight Changes that Should be Recorded in a Weight

and Balance Change Record1

102. How does the operator maintain the OEW?1

103. How often are aircraft weighed?2

Table 1-2. Number of Aircraft to Weigh in a Fleet3

104. What procedures should be used to weigh aircraft?3

Section 2. Aircraft Loading Schedules5

105. What is a loading schedule?5

106. How should an operator determine the weight of each fluid used aboard

the aircraft?5

Section 3. Constructing a Loading Envelope7

107. What should an operator consider when constructing a loading envelope?7

108. What information from the aircraft manufacturer should an operator use?7

109. What should the operator consider when curtailing the manufacturer’s loading

envelope?7

110. What are some examples of common curtailments to the manufacturer’s loading

envelope?8

Section 4. Onboard Weight and Balance Systems11

111. How does an onboard weight and balance system compare to a conventional

weight buildup method?11

112. What measures should an operator take to obtain operational approval for an

onboard weight and balance system?11

113. What operational considerations should an operator take into account when

using an onboard weight and balance system?12

114. May an operator use the information in this AC to develop a backup system?13

CHAPTER 2. METHODS TO DETERMINE THE WEIGHT OF PASSENGERS

AND BAGS15

Section 1. Choosing the Appropriate Method15

Page v

200. What should an operator consider when choosing the appropriate method?15

Section 2. Standard Average Weights17

201. What standard average passenger weights should an operator use with an

approved carry-on bag program?17

Table 2-1. Standard Average Passenger Weights17

202. What standard average weights should an operator use for carry-on bags and

personal items?18

203. What standard average weights should an operator use for checked bags?18

204. What standard average weight should an operator of large cabin aircraft use

for bags checked plane-side?19

205. What standard average weights should an operator of small and medium cabin

aircraft use, if it has a “no-carry-on bag program?”19

Table 2-2. Average Passenger Weights for Operators with a No-Carry-On Bag

Program20

206. What are the standard average weights for crewmembers?20

Table 2-3. Standard Crewmember Weights21

207. What weights may be used for company materials, freight, and mail?21

208. What are the standard average weights for special passenger groups that

do not fit an operator’s standard average weight profile?21

Section 3. Average Weights Based on Survey Results23

209. What should an operator consider when designing a survey?23

210. What sample sizes should an operator use?23

Table 2-4. Minimum Sample Sizes23

211. When conducting a survey, can an operator collect a smaller sample size than

that published in Table 2-4?24

212. What sampling method should an operator use?24

213. What should an operator consider when developing a survey plan and

submitting it to the FAA?25

214. What general survey procedures should an operator use?25

215. What information might an operator gain from conducting a count survey?26

216. When should an operator conduct another survey to revalidate the data from

an earlier survey?27

Section 4. Segmented Passenger Weights28

217. What should an operator consider when using segmented weights?28

Table 2-5. Segmented Weights for Adult Passengers (in Pounds; Summer)28

Page vi

218. How are loading envelope curtailment and bag weight affected by an operator’s

use of segmented weights?28

219. What might be an example be of an operator using the segmented weights in

Table 2-5?29

Section 5. Actual Weight Programs30

220. If the operator decides to use an actual weight program, how might it determine

the actual weight of passengers?30

221. If the operator decides to use an actual weight program, how should it determine

the actual weights of personal items and bags?30

222. What approach should an operator use to record actual weights?30

CHAPTER 3. OPERATOR REPORTING SYSTEMS AND FAA OVERSIGHT31

Section 1. Pilot and Agent Reporting Systems31

300. What are the pilots’ and operators’ responsibilities in reporting aircraft loading

and manifest preparation discrepancies?31

Section 2. FAA Oversight32

301. Which FAA inspectors are responsible for overseeing an operator’s weight

and balance program?32

302. Which portions of OpSpecs or MSpecs are relevant to an operator’s weight and

balance program?32

APPENDIX 1. DEFINITIONS (4 pages)1

APPENDIX 2. SOURCE OF STANDARD AVERAGE WEIGHTS (1 page)1

1. Standard average passenger weights1

2. Standard average bag weights1

Table 2-1. Bag Survey Results1

APPENDIX 3. SAMPLE OPERATIONAL LOADING ENVELOPE (11 pages)1

1. Introduction1

2. Assumptions for this example1

Figure 3-1. Sample Aircraft Interior Seating Diagram1

3. Curtailments for passenger seating variation2

Table 3-1. Calculation of Zone 1 Centroid2

Table 3-2. Calculation of Zone 2 Centroid2

Table 3-3. Calculation of Zone 3 Centroid2

Table 3-4. Moments Resulting from the Zone Centroid Assumption for Zone 13

Page vii

Table 3-5. Moments Resulting from the Window-Aisle-Remaining

Assumption for Zone 13

Table 3-6. Comparison of Moments for Zone 13

Figure 3-2. Sample Passenger Seating Moment (Zone 1)4

Table 3-7. Moments Resulting from the Zone Centroid Assumption for Zone 24

Table 3-8. Moments Resulting from the Window-Aisle-Remaining

Assumption for Zone 25

Table 3-9. Comparison of Moments for Zone 25

Figure 3-3. Sample Passenger Seating Moment (Zone 2)6

Table 3-10. Moments Resulting from the Zone Centroid Assumption for Zone 36

Table 3-11. Moments Resulting from the Window-Aisle-Remaining

Assumption for Zone 37

Table 3-12. Comparison of Moments for Zone 37

Figure 3-4. Sample Passenger Seating Moment (Zone 3)8

4. Other curtailments to the manufacturer’s loading envelope9

5. Operational loading envelope diagrams9

Figure 3-5. Operational Loading Envelope with a Curtailment for Variations

in Passenger Seating10

Figure 3-6. Operational Loading Envelope Using Actual Seating Location

of Passengers11

APPENDIX 4. ADDITIONAL CURTAILMENT TO CG ENVELOPES FOR

PASSENGER WEIGHT VARIATIONS IN SMALL CABIN AIRCRAFT (4 pages)1

Table 4-1. Row Factor1

Table 4-2. Sample Curtailment Due to Variations in Passenger Weight and

Male/Female Ratio Using Window-Aisle Method2

Table 4-3. Sample Curtailment Due to Variations in Passenger Weight and

Male/Female Ratio Using Row Count Method4

APPENDIX 5. OPTIONS TO IMPROVE ACCURACY (4 pages)1

Figure 5-1. Sample Aircraft Interior Seating Diagram2

APPENDIX 6. WEIGHT AND BALANCE CHECKLIST (1 page)1

Page viii

CHAPTER 1. AIRCRAFT WEIGHTS AND LOADING SCHEDULES Section 1. Establishing Aircraft Weight

100. How does an operator establish the initial weight of an aircraft?

Prior to being placed into service, each aircraft should be weighed and the empty weight and CG location established. New aircraft are normally weighed at the factory and are eligible to be placed into operation without reweighing if the weight and balance records were adjusted for alterations and modifications to the aircraft unless some other modification to the aircraft warrants that the aircraft be weighed (e.g., paragraph 103c). Aircraft transferred from one operator that has an approved weight and balance program, to another operator with an approved program, does not need to be weighed prior to use by the receiving operator unless more than 36 calendar-months have elapsed since last individual or fleet weighing, or unless some other modification to the aircraft warrants that the aircraft be weighed (e.g., paragraph 103c). Aircraft transferred, purchased, or leased from an operator without an approved weight and balance program, and that have been unmodified or only minimally modified, can be placed into service without being reweighed if the last weighing was accomplished by an acceptable method (for example, manufacturer’s instructions or AC 43.13-1, Acceptable Methods, Techniques, and Practices—Aircraft Inspection and Repair, current edition) within the last 12 calendar-months and a weight and balance change record was maintained by the operator. See paragraph 103c for a discussion of when it may be potentially unsafe to fail to reweigh an aircraft after it has been modified.

101. How does an operator document changes to an aircraft’s weight and balance?

The weight and balance system should include methods, such as a log, ledger, or other equivalent electronic means, by which the operator will maintain a complete, current, and continuous record of the weight and CG of each aircraft. Alterations and changes affecting either the weight and/or balance of the aircraft should be recorded in this log. Changes in the amount of weight or in the location of weight in or on the aircraft should be recorded whenever the weight change is at or exceeds the weights listed in Table 1-1.

TABLE 1-1. INCREMENTAL WEIGHT CHANGES THAT SHOULD BE RECORDED

IN A WEIGHT AND BALANCE CHANGE RECORD In the weight change record of a— An operator should record any weight changes of— Large-cabin aircraft +/- 10 lb or greater.

Medium-cabin aircraft +/- 5 lb or greater.

Small-cabin aircraft +/- 1 lb or greater.

102. How does the operator maintain the OEW?

The loading schedule may utilize the individual weight of the aircraft in computing operational weight and balance, or the operator may choose to establish fleet empty weights for a fleet or group of aircraft.

Par 100 Page 1

a. Reestablishment of OEW. The OEW and CG position of each aircraft should be reestablished at the reweighing periods discussed in paragraph 103. In addition, it should be reestablished through calculation whenever the cumulative change to the weight and balance log is more than plus or minus one-half of 1 percent (0.5 percent) of the maximum landing weight, or whenever the cumulative change in the CG position exceeds one-half of 1 percent

(0.5 percent) of the mean aerodynamic chord (MAC). In the case of helicopters and airplanes that do not have a MAC-based CG envelope (e.g., canard equipped airplane), whenever the cumulative change in the CG position exceeds one-half of 1 percent (0.5 percent) of the total CG range, the weight and balance should be reestablished.

NOTE: When reestablishing the aircraft OEW between reweighing periods, the weight changes may be computed provided the weight and CG location of the modifications are known; otherwise the aircraft must be reweighed.

b. Fleet Operating Empty Weights (FOEW). An operator may choose to use one weight for a fleet or group of aircraft if the weight and CG of each aircraft is within the limits stated above for establishment of OEW. When the cumulative changes to an aircraft weight and balance log exceed the weight or CG limits for the established fleet weight, the empty weight for that aircraft should be reestablished. This may be done by moving the aircraft to another group, or reestablishing new FOEWs.

103. How often are aircraft weighed?

a. Individual Aircraft Weighing Program. Aircraft are normally weighed at intervals of 36 calendar-months. An operator may, however, extend this weighing period for a particular model aircraft when pertinent records of actual routine weighing during the preceding period of operation show that weight and balance records accurately reflect aircraft weights and CG positions are within the cumulative limits specified for establishment of OEW (see paragraph 102). Under an individual aircraft weighing program, an increase should not be granted which would permit any aircraft to exceed 48 calendar-months since the last weighing, including when an aircraft is transferred from one operator to another. In the case of helicopters, increases should not exceed a time that is equivalent to the aircraft overhaul period.

NOTE: Per section 125.91(b), no person may operate an airplane in a part 125 operation, unless the current empty weight and CG are calculated from the values established by an actual weighing of the airplane within the preceding 36 calendar-months.

b. Fleet Weighing. An operator may choose to weigh only a portion of the fleet every 36 months and apply the weight and moment change determined by these sample weighings to the remainder of the fleet. For each aircraft weighed, the new aircraft empty weight (and moment) is determined by the weighing and entered in the aircraft weight log. The difference between this new aircraft weight (and moment) and the previous aircraft weight (and moment) shown in the log is the unaccounted weight (and moment) change. The average of the unaccounted weight and moment changes for the aircraft weighed as part of this fleet weighing Page 2 Par 102