AC 133-1B

Historical

Advisory circular · Rotorcraft External-Load Operations

A newer version is currentThis is a historical version. AC 133-1B CHG 1 is the version in force, approved March 16, 2020.
Approved
May 31, 2017
Last reviewed
August 30, 2024
Cancels
AC133-1A
Cancelled by
AC133-1B CHG 1
Family
AC 133-1 · 3 versions
Revision
B
14 CFR parts
133, 27, 29, 91, 21

Guidance, not mandatory unless a rule or AD requires it. DRS record last changed November 21, 2025.

U.S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Rotorcraft External-Load Operations Date: 5/31/17 AC No: 133-1B Initiated by: AFS-800 Change:

This advisory circular (AC) provides background information, describes rotorcraft external-load operations, and describes an acceptable means, but not the only means, to apply for and obtain authorization to conduct rotorcraft external-load operations under Title 14 of the Code of Federal Regulations (14 CFR) part 133. Federal Aviation Administration (FAA) personnel will provide the necessary materials and information during the application process. This AC also provides guidance and information for certificated rotorcraft external-load operators. The information in this AC and related reading material will assist you in completing the application process in an efficient and accurate manner.

ORIGINAL SIGNED by /s/ John S. Duncan Director, Flight Standards Service

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CONTENTS Paragraph Page

Chapter 1. General1-1

1.1 Purpose of This Advisory Circular (AC)1-1

1.2 Audience1-1

1.3 Where You Can Find This AC1-1

1.4 What This AC Cancels1-1

1.5 Applicability1-1

1.6 Related Regulations1-1

1.7 Related Reading Material1-2

1.8 Definitions1-2

1.9 Background1-3

1.10 AC Feedback Form1-4

Chapter 2. Certification Process and Rules2-1

2.1 Application Process2-1

2.2 Phase 1 and Phase 2—Preapplication and Application2-1

2.3 Phase 3—Document Compliance2-4

2.4 Phase 4—Demonstration and Inspection2-9

2.5 Phase 5—Certification2-13

Chapter 3. Operating Rules and Requirements3-1

3.1 Operating Rules3-1

3.2 Congested Area Operations3-1

3.3 Carriage of Persons3-8

3.4 Human External Cargo (HEC)3-9

3.5 Night Operation Considerations, Limitations, Training, and Risk Mitigation

Procedures (if applicable)3-14

3.6 Pu

blic Aircraft Operations (PAO)3-15

Chapter 4. Airworthiness Requirements4-1

4.1 Operations Flight Characteristic Demonstration4-1

4.2 Rotorcraft Type Certification Requirements4-1

4.3 External-Load Attaching Means4-3

4.4 Quick-Release Devices4-4

4.5 Portable Safety Devices (PSD)/Belly Bands4-4

4.6 Airworthiness Regulations and Limitations4-6

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Appendix A. Sample Rotorcraft-Load Combination Flight ManualA-1

Appendix B. Hand SignalsB-1

Appendix C. Possibility of D-Ring Reversal or Dynamic Rollout During Winching or

Long Line OperationsC-1

List of Figures

Figure 2-1. FAA Form 8400-6, Preapplication Statement of Intent2-14

Figure 2-2. Sample FAA Form 8710-4, Rotorcraft External-Load Operator

Certificate Application2-16

Figure 2-3. Sample Letter of Nomination for Designation as a Chief Pilot2-17

Figure 2-4. Certification Process Flowchart2-18

Figure 3-1. Sample Congested Area Plan3-5

Figure 3-2. Letter of Agreement for Congested Area3-8

Figure C-1. Example of D-Ring ReversalC-1

Figure C-2. MS 18027-2A HookC-2

Figure C-3. Hook with a Mechanical Lock Latch Gate DesignC-2

Figure C-4. Hook with a Simple Spring- Loaded Safety Latch or KeeperC-3

1-1 CHAPTER 1. GENERAL

1.1 Purpose of This Advisory Circular (AC). This AC provides background information, describes rotorcraft external-load operations, and describes an acceptable means, but not the only means, to apply for and obtain authorization to conduct rotorcraft external-load operations under Title 14 of the Code of Federal Regulations (14 CFR) part 133. Federal Aviation Administration (FAA) personnel will provide the necessary materials and information during the application process. This AC also provides guidance and information for certificated rotorcraft external-load operators. The information in this AC and related reading material will assist you in completing the application process in an efficient and accurate manner. To be eligible for a Rotorcraft External-Load Operating Certificate, an operator must meet the following eligibility requirements:

1. The applicant must have the exclusive use of at least one rotorcraft that meets the requirements of part 133, § 133.19.

2. The applicant must hold, or have available the services of at least one person who holds, a current commercial or Airline Transport Pilot Certificate (ATPC) with a rating appropriate for the rotorcraft prescribed in § 133.19, issued by the Administrator.

1.2 Audience. This AC applies to all operators seeking a part 133 Operating Certificate and all operators that currently have a part 133 Operating Certificate.

1.3 Where You Can Find This AC. You can find this AC on the FAA’s website at http://www.faa.gov/regulations_policies/advisory_circulars.

1.4 What This AC Cancels. AC 133-1A, Rotorcraft External-Load Operations in Accordance with Federal Aviation Regulations Part 133, dated October 16, 1979, is cancelled.

1.5 Applicability. This AC provides information for persons interested in applying for a Rotorcraft External-Load Operating Certificate.

1. A 14 CFR part 137 agricultural aircraft operator may, if he or she complies with part 137, conduct agricultural aircraft operations with a rotorcraft with external dispensing equipment in place without a part 133 Rotorcraft External-Load Operating Certificate.

2. The holder of a Rotorcraft External-Load Operating Certificate under part 133 need not comply with part 137 subpart B certification rules when conducting an agricultural aircraft operation involving only the dispensing of water on forest fires by rotorcraft external-load means. However, part 137 subparts A, C, and D apply.

1.6 Related Regulations. Title 14 CFR parts 1, 21, 27, 29, 61, 91, and 133 and 49 CFR parts 100–175 (hazardous materials (hazmat)). The current CFRs can be accessed at https://www.ecfr.gov.

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1.7 Related Reading Material (current editions). The following websites and references provide additional information related to this AC:

1. FAA ACs. The following are available at http://www.faa.gov/regulations_policies/advisory_circulars/:

• AC 27-1, Certification of Normal Category Rotorcraft.

• AC 91-32, Safety In and Around Helicopters.

• AC 91-42, Hazards of Rotating Propeller and Helicopter Rotor Blades.

• AC 120-92, Safety Management Systems for Aviation Service Providers.

2. FAA Handbooks and Manuals.

• FAA-H-8083-21, Rotorcraft Flying Handbook, available at http://www.faa.gov/regulations_policies/handbooks_manuals/.

• Safety Risk Management, available at https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/risk_mana gement/.

3. FAA Orders and Notices. Available at http://www.faa.gov/regulations_policies/orders_notices/.

4. Other Materials.

• International Helicopter Safety Team (IHST) Safety Management System Toolkit at http://www.ihst.org/Portals/54/2009_SMS_Toolkit_ed2_Final.pdf.

• Utilities, Patrol and Construction (UPAC) Safety Guide for Helicopter Operators at http://www.rotor.org/portals/1/committee/upac_guide.pdf.

1.8 Definitions. The following paragraphs define rotorcraft external-load combinations and designations, and describe Operating Certificate requirements. Rotorcraft-load combinations (RLC) are defined as follows:

1. Class A Rotorcraft-Load Combination (RLC). The external load cannot move freely, cannot be jettisoned, and does not extend below the landing gear.

An example of a Class A load is the carriage of items in an approved cargo rack, bin, or fixture attached to the exterior of the aircraft. A cargo rack certification may or may not include a cargo envelope. The FAA-approved Rotorcraft Flight Manual Supplement (RFMS) required for the cargo rack installation specifies the approved configuration. If the cargo carried is within the envelope specified in the RFMS, the rotorcraft operator may operate in accordance with 14 CFR part 91 or 135. Rotorcraft operators must conduct flight operations in accordance with part 133 when the cargo rack certification does not include a cargo envelope or the cargo carried exceeds the specified envelope.

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2. Class B RLC. The external load is jettisonable, carried above or below the skids, and lifted free of land or water during the rotorcraft operation.

An air conditioner unit being lifted onto the roof of a tall building is an example of a Class B load.

3. Class C RLC. The external load is jettisonable and remains in contact with land or water during the rotorcraft operation. Wire stringing, dragging a long pole, and boat towing are some examples of Class C loads.

4. Class D RLC. The external load is other than Class A, B, or C and approved on an individual basis through the issuance of Letter of Authorization (LOA) A044, Class D Operations Involving Carriage of Persons, using the Web-based Operations Safety System (WebOPSS). Only approved Class D operations allow carriage of a person other than a crewmember or person who is essential and directly connected with the external-load operation, in an FAA-approved personnel lifting device with a transport Category A multiengine helicopter. A harbor pilot being transported externally to or from a ship utilizing a personnel lifting device or a person being rescued utilizing a personnel lifting device are examples of Class D loads. Any other carriage of persons under part 133 must be in accordance with § 133.35.

5. External Load. A load that is carried, or extends, outside the aircraft fuselage.

6. Human External Cargo (HEC). A person(s) that at some point in the operation is carried external to the rotorcraft.

7. Non-Human External Cargo (NHEC). Any external cargo operation that does not at any time involve a person(s) carried external to the rotorcraft.

1.9 Background. Rotorcraft external-load operations in the United States have steadily increased over the past two decades. The FAA’s General Aviation and Part 135 Activity Survey estimated that, in 2015, operators flew 175,000 hours under part 133. Since publication of AC 133-1A in 1979, several amendments have been made to part 133.

While some changes were administrative in nature, others affected the operating, airworthiness, and certification rules for external-load operators.

1.9.1 Amendment 133-9. In November 1986, as part of its Rotorcraft Regulatory Review Program, the FAA published Amendment 133-9. This amendment:

• Defined “Class D rotorcraft-load combinations” in part 1 and prescribed the operational rules for Class D loads;

• Changed the applicability of the certification requirements for certain types of operations;

• Updated personnel requirements;

• Amended knowledge and skill requirements;

• Simplified Operating Certificate amendment procedures;

• Defined requirements for flight under instrument flight rules (IFR);

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• Amended flight characteristics demonstration requirements; and

• Simplified the process for adding rotorcraft to an Operating Certificate.

1.9.2 Amendment 133-12. In March 1990, also as part of the Rotorcraft Regulatory Review Program, the FAA published Amendment 133-12. This amendment adopted new airworthiness standards for external-load attaching means as defined by parts 27 and 29.

The operational rules were also revised to allow use of external-load attaching means and quick-release devices approved under part 21, as long as they comply with the applicable provisions of part 27 or 29.

1.10 AC Feedback Form. For your convenience, the AC Feedback Form is the last page of this AC. Note any deficiencies found, clarifications needed, or suggested improvements regarding the contents of this AC on the Feedback Form.

2-1 CHAPTER 2. CERTIFICATION PROCESS AND RULES

2.1 Application Process. The application process is designed to ensure that you, the operator, meet the requirements for certification under 14 CFR part 133.

If satisfactorily completed, the application process will result in issuance of a Rotorcraft External-Load Operating Certificate and any additional authorizations.

2.1.1 Certification Process Phases. There are five phases in the application process (see Figure 2-4, Certification Process Flowchart):

1. Preapplication (combined with Formal Application Phase in most instances),

2. Formal Application,

3. Document Compliance,

4. Demonstration and Inspection, and

5. Certification.

Note: The part 133 certification process combines Phase 1, Preapplication, and Phase 2, Application.

2.1.2 Certification Process Gates. Included in the five phases are three gates. The three gates are points in the process at which requirements must be met before proceeding to the next part of the application process.

Note: Certain cases may dictate that the guidance and suggested sequence of events in this AC be modified. In such situations, the applicant and the local Flight Standards District Office (FSDO) should consider existing conditions and circumstances. The FAA will not issue an Operating Certificate until it determines that all requested authorizations can be conducted in a safe manner and all applicable FAA regulations, guidance, and policy have been complied with.

2.2 Phase 1 and Phase 2—Preapplication and Application.

2.2.1 Applicant Resources.

1. To start a part 133 application, contact the local FSDO for your primary business address. The FSDO will provide the applicant with the appropriate information and references needed to begin the certification process.

The applicant should be aware of the certification and operating requirements of part 133. The FSDO personnel will explain:

• The general applicability and definition of terms.

• The certification requirements.

• The operating rules.

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• Part 133 recordkeeping requirements.

• The requirement to comply with other Federal, State, and local regulations.

2. Special considerations include:

• Load class authorizations A, B, C, or D.

• Instrument flight rules (IFR) authorization requirements.

• Qualifications and experience required for the Chief Pilot.

• Rotorcraft-Load Combination Flight Manual (RLCFM) requirements.

• Training program requirements for Class D operations.

• Hazardous materials (hazmat) training program, if applicable.

2.2.2 FAA Form 8400-6, Preapplication Statement of Intent. Complete the Preapplication Statement of Intent (PASI) (available at http://www.faa.gov/forms) and submit it to the FSDO (see Figure 2-1, FAA Form 8400-6, Preapplication Statement of Intent). Upon receipt of a signed PASI, the FSDO will review the form to ensure that there is sufficient information to further process the preapplication and that the proposed operation is consistent with part 133. The PASI must contain the following:

• The company legal name, including any doing business as (DBA) names, the principal base of operations address, the mailing address, phone numbers, and the planned date when operations will begin.

• Names of management personnel and the Chief Pilot.

• Type, make, model, and quantity of rotorcraft operated.

• All desired authorizations (e.g., Class A, B, C, or D or IFR) in block 10.

Note: If the PASI is unacceptable, the FSDO will describe the reasons why it is unacceptable in section 2 of the form and return it. The FSDO will notify the applicant, either verbally or by letter, that the PASI is unacceptable for the reasons detailed in section 2 of the form and that a new PASI is required.

2.2.3 Application Package.

1. FSDO personnel will provide the applicant with the following materials or refer you to the current online resource:

• FAA Form 8710-4, Rotorcraft External-Load Operator Certificate Application (see Figure 2-2, Sample FAA Form 8710-4, Rotorcraft External-Load Operator Certificate Application).

• Sample Letter of Nomination for Designation as a Chief Pilot (see Figure 2-3).

• Sample Rotorcraft-Load Combination Flight Manual (see Appendix A).

2. FSDO personnel will discuss how to complete the forms and advise the applicant to submit the forms with original signatures.

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3. The following factors will be used to determine if additional items need to be discussed with the applicant:

• Previous experience in part 133 external-load operations;

• Size, scope, and safety aspects of the requested operation;

• Area of operation;

• Class D or IFR authorization, if requested; and

• Ability to comply with the certification requirements.

4. FSDO personnel will discuss the following with the applicant and answer any questions about the certification process:

• The time and gate requirements for the completion of each phase;

• Area of operation (local or across FSDO boundaries), including the location of the principal base of operations, and the location of any probable satellite bases;

• Load class authorization(s) the operator is seeking;

• Operator’s previous experience with part 133 operations;

• Qualifications and experience of the proposed Chief Pilot;

• Applicability of 14 CFR parts 91 and 133;

• AC 133-1, Rotorcraft External-Load Operations;

• Previous or pending enforcement action against the applicant or pilot(s);

• Contents of the RLCFM; and

• Requirements for developing a training program for Class D operations.

2.2.4 Application Review. If the application package is not complete, the FSDO will notify the applicant in writing of the changes needed before certification can continue. An example of a properly completed application form is shown in Figure 2-2. An indepth review of the package will be conducted during the Document Compliance Phase.

2.2.5 Application Meeting. After the application review process is completed, an application meeting will be scheduled to discuss:

• A schedule for certification, and any necessary adjustments.

• The requirements for each load class authorization requested.

• The requirements for the RLCFM.

• The rotorcraft ownership or lease agreement.

• The applicant’s previous experience in external-load operations.

• The experience and qualifications of the designated Chief Pilot.

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• The requirements for an IFR authorization, if applicable.

• The requirements for a Class D training program, if applicable

2.2.6 Gate Complete. All steps in the Application Phase must be completed before continuing to the Document Compliance Phase (see Figure 2-4). If the applicant does not complete this phase within 90 days of the FSDO’s receipt of the PASI, the FSDO may need to end the certification process. Completion of this gate triggers a new 90-day completion timeline for the Document Compliance Phase.

2.3 Phase 3—Document Compliance.

2.3.1 Application Form (FAA Form 8710-4).

1. In block 1, the applicant indicates the following:

• “Original Issuance” if the application is for initial certification;

• “Amendment” if the application is for a change to an existing certificate; or

• “Renewal” if the application is for renewal of an existing certificate.

2. In block 1, the applicant enters the certificate number if the application is for amendment or renewal, and checks the appropriate block(s) to indicate the load classes requested.

3. In block 2, the applicant indicates the name (including DBAs), mailing address, and telephone number of the operator.

4. In block 3, the applicant indicates the address and telephone number of the principal or local base of operations. Verify the applicant has not used a post office box number in this block.

5. In block 4, the applicant indicates the name of the Chief Pilot or designee and that pilot’s Airman Certificate grade (e.g., private, commercial, and airline transport pilot (ATP)) and certificate number.

6. In block 5, the applicant indicates all rotorcraft to be used by registration number, make, and model. The applicant also indicates the requested load classes and whether the attaching device for each rotorcraft has been previously approved by the FAA. The applicant may use the remarks column to indicate which rotorcraft will be used in IFR operations.

7. At the bottom of the form, the applicant or authorized officer must date and sign the application. The person signing the application must also include their title (e.g., Director of Operations or President).

8. The reverse side of the form is completed by the FAA during the Certification Phase.

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2.3.2 Rotorcraft Lease. The rotorcraft lease must list:

• Name(s) of owner(s);

• Name of certificate holder/applicant;

• Identification and type of rotorcraft;

• Duration of lease (6 month minimum);

• Indication of sole possession, control, and use for flight, including an agreement for performance of required maintenance; and

• Signatures of the owners and certificate holder or applicant, to include dates.

2.3.3 RLCFM. See Appendix A for a sample RLCFM which includes a detailed description of the required content.

1. Authority. Part 133, § 133.47 requires the operator to develop an RLCFM as part of the application package for certification of rotorcraft external-load operations. Section 133.47(a) requires the RLCFM to include the operating limitations, procedures, performance, and other information established under §§ 133.41–133.51. This includes the information established during operational flight checks performed under § 133.41. The operator should place limitations, procedures, performance, and other information not included in the approved Rotorcraft Flight Manual (RFM) into the RLCFM.

2. Content. Section 133.47 outlines instructions and specifications for the contents of the RLCFM. Title 14 CFR part 27 subpart G or part 29, whichever is applicable, requires the establishment of operating limitations and other information necessary for safe operation. The RLCFM provides a means of conveying this information to the crewmembers.

3. Purpose. The RLCFM is a required document that provides the information necessary for the safe carriage of external loads.

4. Developing an RLCFM. The RLCFM must cover each class of external-load operation conducted with a specific rotorcraft. The operator must prepare an RLCFM for each rotorcraft, even if some makes and models are similar.

The manufacturer’s calculation of performance data and operating limitations may be unique for each rotorcraft. An operator planning to add or delete a load class must revise the RLCFM accordingly to reflect the safety considerations.

5. Initiation. The applicant for a part 133 external-load Operating Certificate must submit two copies of an RLCFM for review and approval, or one electronic copy, if acceptable, to the FSDO. The applicant must prepare the RLCFM in conformance with part 27 subpart G or part 29 subpart G.

2.3.4 Letter of Designation of Chief Pilot. Upon issuance and acceptance of the Letter of Designation, both the operator and Chief Pilot must sign the letter.