2-5 requirements and/or limitations (per 14 CFR part 43, § 43.5(c), § 121.135, and § 135.413).
2.2.2.5.3 In cases of multiple STCs applied to a single aircraft, the STCs should be evaluated for effect on each other and on the appropriate limitations applied.
At a minimum, an operator should include the supplemental information described above and cross-reference the supplemental information in the operator’s WBM. In addition, the operator should organize the supplemental information in a way that facilitates use by trained and qualified personnel.
2.2.2.6 Aircraft CLS Limitations. The operator must act in accordance with and apply the W&B and CG limitations of the aircraft CLSs, as established by the DAH WBM as operating limitations (per § 91.9). The operator should consider all limitations established by the DAH. The operating limitations are defined within the WBM. The WBM may allow for the reconfiguration of the CLS. The operator should have a method to determine W&B calculations for any reconfiguration of a CLS. When the operator modifies the aircraft, such as adopting a CLS STC, the associated instructions for continued airworthiness (ICA) are also incorporated into its maintenance and/or inspection program.
The operator should include the supplemental information provided by the ICAs in the operator’s WBM, and any charts or tables that indicate proper weight and CG range limitations.
2.2.2.7 Carriage of Other Persons (Other than Flightcrew). Sections 121.583,
125.331, and 135.85 permit, under certain circumstances, the carriage of persons aboard an airplane without compliance with certain passenger-carrying requirements of parts 121, 125, and 135, respectively.
They may be carried aboard an airplane because of their necessity for the safety of the flight, their relationship with the air carrier, or by virtue of certain knowledge and abilities attributed to them through selection and training. An operator must establish procedures for the carriage of other authorized persons. At a minimum, the procedures should address:
1. A method for calculating the weight of other authorized persons and their carry-on and checked baggage, such as actual weight or standard average weight (refer to AC 120-27 for guidance on calculating weights);
2. Any special procedures or limitations when carrying other authorized persons aboard an aircraft. These limitations are specified by the exemption, if required, for the carriage of other authorized persons; and
3. Instructions for documenting the weight of other authorized persons, and for communicating the information to the pilot in command (PIC) or other authorized, trained, and qualified personnel for determining W&B.
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2.3 Classifying Cargo Compartment for Fire Suppression, CLS Components, Installed Nets, and Smoke Barriers.
2.3.1 Classification of Cargo Compartments for Fire Suppression. Aircraft cargo compartments are designed to accept and restrain cargo in various ways. Cargo compartments are classified as Class A, B, C, E, or F, depending on accessibility and fire protection requirements. Under § 25.857, cargo compartments are classified as follows:
1. A Class A compartment is one in which:
• The presence of a fire would be easily discovered by a crewmember while at their stations, and
• Each part of the compartment is easily accessible in flight.
2. A Class B compartment is one in which:
• There is sufficient access in flight to enable a crewmember, standing at any one access point and without stepping into the compartment, to extinguish a fire occurring in any part of the compartment using a hand fire extinguisher;
• When the access provisions are being used, no hazardous quantity of smoke, flames, or extinguishing agent will enter any compartment occupied by the crew or passengers; and
• There is a separate approved smoke detector or fire detection system to give warning at the pilot or Flight Engineer (FE) station.
3. A Class C compartment is one not meeting the requirements for either a Class A or B, but in which:
• There is a separate approved smoke detector or fire detection system to give warning at the pilot or FE station;
• There is an approved built-in fire extinguishing or suppression system controllable from the cockpit;
• T here are means to exclude hazardous quantities of smoke, flames, or extinguishing agent from any compartment occupied by the crew or passengers;
and
• There are means to control ventilation and drafts within the compartment so that the extinguishing agent used can control any fire that may start within the compartment.
4. A Class E compartment is one on airplanes used only for the carriage of cargo, and in which:
• There is a separate approved smoke or fire detection system to give warning at the pilot or FE station;
• There are means to shut off the ventilating airflow to or within the compartment, and the controls for these means are accessible to the flightcrew in the crew compartment;
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• There are means to exclude hazardous quantities of smoke, flames, or noxious gases from the flightcrew compartment; and
• The required crew emergency exits are accessible under any cargo loading condition.
5. A Class F compartment must be located on the main deck and is one in which:
• There is a separate approved smoke detector or fire detection system to give warning at the pilot or FE station;
• There are means to extinguish or control a fire without requiring a crewmember to enter the compartment; and
• There are means to exclude hazardous quantities of smoke, flames, or extinguishing agent from any compartment occupied by the crew or passengers.
2.3.2 Cargo Compartments Designed to Accept ULDs. These compartments are equipped with an aircraft CLS designed to restrain ULDs in the aircraft. The CLS comprises various assemblies, such as restraint locks, side rails, and ball and roller conveyors. Some CLSs are powered, and some may be installed in main deck and/or lower deck compartments.
When the flightcrew and/or other persons are seated forward of the CLS, a smoke barrier should be installed (as applicable) between the CLS and those persons. In addition to a smoke barrier, protection of the occupants in an emergency landing is also required per §§ 25.561(a) and 25.853(e).
2.3.3 Cargo Compartments Not Designed to Accept ULDs.
2.3.3.1 These cargo compartments are called bulk compartments, and may have vertical or horizontal nets. Depending on its design and purpose, the net may restrain cargo from shifting vertically, longitudinally, and laterally within the compartment or from shifting onto the cargo door or cargo door area within the compartment. Bulk compartments protect aircraft systems and structures against damage from shifting cargo for all flight and landing conditions.
2.3.3.2 Some aircraft cargo compartments are versatile in that they may accept both authorized ULDs and bulk cargo. These compartments may also have a CLS to help in the movement of ULDs. The certification documents, either TC or STC, are the approval basis for these combined compartments. The combination bulk/ULD compartments can be found in the lower lobe and upper decks of appropriately certificated aircraft.
Note: Care should be taken when loading bulk cargo in these compartments to ensure that it does not block fire detection sensors or fire suppression agent nozzles, if installed.
2.3.4 Reconfiguring the CLS. The CLS contain components such as rails and locks that move and/or interchange in order to change the configuration of the CLS. An operator may
2-8 move/interchange these components using the DAH instructions that are typically found in one of the following source documents:
• TC, STC, and Type Certificate Data Sheets (TCDS);
• Service Bulletins (SB) or Service Letters (SL), if incorporated by reference into a mandatory advisory directive (AD); and
• Manufacturers’ ICAs.
2.3.5 Owner-Produced Parts. Section 21.9 provides that an owner or operator may manufacture replacement and modification parts for use on its own aircraft. As it pertains to this AC, an operator or owner should have processes to:
1. Identify components manufactured for the aircraft CLS in its maintenance program;
2. Ensure another operator or vendor does not sell or distribute the parts it manufactures;
3. Show its owner-produced parts meet the equipment manufacturer CLS type design; and
4. Maintain the continued airworthiness of the owner-produced part.
2.3.6 Addressing CLS Component Discrepancies. An operator may address aircraft CLS component discrepancies by replacing or repairing the applicable component. If the operator discovers systemic problems with the reliability of its components, the operator should report such problems to the component manufacturer. An operator’s CASS should track all cargo loading component discrepancies to measure the performance and effectiveness of the operator’s maintenance and inspection program.
2.3.7 Replacing a CLS Component. An operator may replace a CLS component with a new, rebuilt, overhauled, or repaired serviceable component, in accordance with any applicable regulations.
2.3.8 Repairing a CLS Component.
2.3.8.1 Operator Responsibility. An operator may repair a component on the aircraft, or may have a vendor repair a component, in accordance with applicable regulations. Under certain circumstances, an accepted manual may allow minor repairs. The repair vendor may be under the direct control of an operator, or may be a vendor the operator designates. The operator has primary responsibility for determining that the component meets applicable regulatory requirements.
2.3.8.2 Vendor Repair. CLS components repaired by a vendor should undergo a receiving inspection using operator procedures. The component should also have documentation to (1) confirm each component is certified as serviceable,
2-9 and (2) provide traceability to the data used for repair. The documentation should include:
1. Identity of the company that owns the component;
2. FAA repair station certificate number, if applicable, and vendor name;
3. Component part number;
4. Component serial number, if applicable;
5. Component nomenclature;
6. Component times and/or cycles, if applicable;
7. Quantity of components;
8. Specifications used for repair;
9. Certification statement of procedures used; and
10. Traceability documentation.
2.3.8.3 Retention of Repair Records. The operator must retain its repair records per the requirements of §§ 121.380 and 135.439.
2.3.9 CLS Components in the Minimum Equipment List (MEL).
2.3.9.1 Operator Procedures. An operator wanting to place CLS components on an aircraft MEL must ensure the aircraft MEL for those components contains adequate instructions and procedures to meet the requirements of §§ 121.628 and 135.179. These procedures should identify:
1. The total number of items installed and minimum number required for dispatch;
2. The loading limitations because of missing or defective equipment;
3. The references showing the location of loading restrictions;
4. The appropriate category for repair; and
5. The instructions for ensuring MEL limitations are included in W&B computations and the load plan.
2.3.9.2 Procedures for Inoperative or Removed CLS Components. An operator should include procedures for inoperative or removed CLS components in the operator MEL. These procedures should include any requirements for:
1. Reconfiguration of the aircraft, if necessary;
2. Voiding of adjacent positions, if necessary;
3. Accounting for limitations;
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4. Notification to the PIC and other appropriate personnel the operator deems necessary of the inoperative components;
5. Instructions for ensuring MEL limitations and/or restrictions are included in W&B computations and the load plan; and
6. Annotation in the aircraft maintenance logbook.
2.3.10 nstalled Nets in the Maintenance Program. An operator maintenance program should contain procedures for maintenance and inspection of installed vertical and horizontal cargo compartment nets and 9g barrier nets. The program should encompass:
1. In-house or vendor repair procedures;
2. Receiving inspection procedures; and
3. Serviceability limitations.
2.3.11 Smoke Barriers and Nets.
2.3.11.1 Smoke Barrier Control Procedures. A smoke barrier is intended to act as a blockade between the cargo and crew, preventing smoke and flames from entering the passenger cabin and flight deck areas of the aircraft. They can be permanent or attachable and in a variety of forms, such as doors or curtains.
An operator must have procedures to control the airworthiness and subsequent operational serviceability of smoke barriers (per §§ 121.367 and 135.425).
The operator should provide aircraft-specific training on the description, operation, function, and preflight of smoke barriers.
2.3.11.2 Inspection. Operators should inspect the overall condition of the smoke barrier curtain (if installed), cockpit door seal, barrier net assembly, or solid bulkhead as required by the carrier’s maintenance manual. Inspections should include, at a minimum:
1. The smoke barrier curtain, which must be free of tears, holes, and cuts to prevent smoke from entering the forward cabin and flight deck;
2. The cockpit door seal, for condition and integrity;
3. The barrier net, for condition and security (i.e., check for frayed straps, hardware integrity, and proper markings);
4. Cargo compartment retention nets, for condition and security;
5. The solid bulkhead, for condition and security; and
6. The required placards (such as loading, fire suppression, and so forth) for condition, legibility, and security.
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2.4 ULDs and Cargo Restraint Devices.
2.4.1 Restraints. Aircraft cargo restraint methods have two general categories: primary and supplemental.
2.4.1.1 Primary Restraint. Primary restraint is the restraint of the cargo payload to the aircraft structure through the CLS or directly to tiedown points approved in the WBM. This restraint secures cargo in the forward, aft, vertical, and lateral directions. Primary restraint is used to secure:
2.4.1.1.1 Cargo.
1. To a pallet using a WBM-authorized net as the primary restraint;
2. Within a container (the container is the primary restraint);
3. To the aircraft structure as special cargo (straps, ropes, etc., are the primary restraint); or
4. To the ULD (pallet) using straps or ropes, as the primary restraint is considered special cargo.
2.4.1.1.2 ULD. To the aircraft structure using the CLS, such as locks and side rails.
2.4.1.1.3 Other Aircraft Restraints Per WBM Provisions. Some airplane WBMs may provide for additional tiedown to the aircraft structure to restrain ULDs if the following conditions exist:
1. The ULD allowable weight may be limited either by restraint configurations or by missing and/or inoperative restraints; or
2. The ULD is loaded to a weight greater than allowable for the chosen loading position with all restraints operative, and a greater weight is allowed by the aircraft WBM with tiedown (e.g., the floor is more capable than the restraint system).
Note: See paragraph 2.8 for additional guidance.
2.4.1.2 Supplemental Restraint. Supplemental restraint is additional restraint that prevents shifting and is used to stabilize cargo to a pallet or container. When supplemental restraints are attached to a CLS or aircraft structure, it creates a parallel load path to the ULD and is therefore classified as special cargo (see paragraph 2.8 for additional guidance). An exception would be straps or ropes used to prevent shifts or stabilize cargo in a certified bulk compartment.
Operators may use supplemental straps at their discretion as long as the primary means of restraint has been complied with.
2.4.2 ULD Description. A ULD is a device for grouping, transferring, and restraining cargo for transit. It consists of a pallet with a net, or it may be a container. ULDs are defined in National Aerospace Standard (NAS) 3610, Cargo Unit Load Devices—Specification for;
2-12 Aerospace Standard (AS) 36100, Air Cargo Unit Load Devices—Performance Requirements and Test Parameters; and Technical Standard Order (TSO)-C90, Cargo Pallets, Nets and Containers (Unit Load Devices). The term “ULD” includes the equipment in paragraph 2.4.3 below.
Note: Cargo restrained on a pallet by straps is not a ULD.
2.4.3 Types of ULDs.
2.4.3.1 Background:
1. Authorized ULDs are defined in aircraft WBMs and require no further analysis.
2. Some ULD designs may exceed the structural capability of an aircraft. To preclude failures of the aircraft cargo restraint system, operators must meet the requirements of the aircraft WBM, as this is an operating limitation that is part of the AFM and must be complied with per §§ 91.9, 23.2620, and 25.1583.
2.4.3.2 Certified ULDs. A ULD meeting the requirements of TSO-C90; STC requirements, if applicable; or other FAA-approved certification standards. A certified ULD is structurally capable of restraining a load and/or protecting the aircraft systems and structure. Only ULDs that are authorized by the aircraft WBM (TC or STC) are authorized for use on that aircraft. To remain an authorized ULD for an aircraft, the ULD must be restrained by the aircraft’s CLS in accordance with the aircraft’s WBM, as an operating limitation contained in the AFM (per § 91.9). Examples of restraining ULDs by the aircraft’s CLS include pallet locks and side guides. A certified pallet and the corresponding certified net is a certified unit, as defined by the WBM.
2.4.3.3 Approved Cargo Pallet and Net (ULD). Most operator WBMs recognize a TSO cargo pallet and net combination as the primary restraint for unitized cargo. A cargo pallet net is the only restraint device that takes the shape of the cargo while restraining the load in all directions, so that the load is spread to the net fittings and pallet edge rails.
2.4.3.4 Noncertified ULDs. A ULD that does not meet the TSO-C90 or TC/STC certification requirements.
2.4.3.5 Active ULDs. Active ULDs include powered systems, such as temperature control and fire suppression systems. Active ULDs use batteries of multiple types to power these systems, and the manufacturers frequently integrate electrical wiring, fans, and components that should be able to withstand the handling, loading, and transport environments. Active ULDs are intended to be operating during flight. Active ULDs are battery-powered in flight and are only recharged while on the ground. Commonly used active ULDs are temperature-controlled containers. These systems consist of a highly insulated
2-13 container with a battery-operated heating/cooling system integrated into the construction of the container.
2.4.3.5.1 Active ULD Operational Approval and Use. Using active ULDs that interface with the pilot or aircraft avionics or electronic systems likely requires an STC If you intend to deploy these containers in your fleet, you should understand and assess the hazards of active ULDs before carrying such devices.
Additionally, you should incorporate or reference the pertinent parts of the aircraft certification documents into your manual and have procedures to ensure the containers meet the handling and airworthiness requirements of the manufacturer. These may include:
• Required markings, placards, and labeling;
• ICAs, to include proposed limitations and restrictions necessary to safely carry the device on an aircraft; and
• Operating instructions for the device.
2.4.4 Other Restraint Devices.
2.4.4.1 Other Types of Cargo Restraint Devices. The operator may use cargo restraints such as straps, ropes, chains, and nets. The use of these types of restraints must not be contrary to aircraft manufacturer W&B documentation or STC holder documentation (per §§ 23.2620, 25.1583, and 43.13(c)). If the operator does not use an approved cargo pallet/net combination as the primary restraint, the operator’s manual should have policies and procedures to address this issue. For example, if a strap is used as the primary restraint, the cargo may be:
1. Loaded in an aircraft compartment that meets the type design for compartment restraint; or
2. Restrained by cargo straps or other authorized devices to the aircraft as described in the aircraft’s manual, an STC supplement, or a WBM.
2.4.4.2 Certified Restraint Straps. In TSO-C172, Cargo Restraint Strap Assemblies, the FAA describes the minimum performance standards (MPS) by which cargo restraint strap assemblies are pproved and identified with applicable TSO markings. Newer straps may have expiration dates marked on the straps.
2.4.5 Determining ULD Compatibility. It is critical to safety of flight for the operator to have procedures confirming that ULDs on board an aircraft are compatible with the aircraft, regardless of who owns the ULD. Not all ULDs are authorized as compatible with all aircraft, so an operator should have procedures for:
2.4.5.1 Authorization. Ensure ULDs are authorized for carriage on the specific aircraft by the DAH WBM.
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2.4.5.2 Communication. Inform employees and vendors loading aircraft converted from passenger to all-cargo by an STC that the aircraft could have different ULD requirements than other STC conversions or production aircraft configurations in the operator’s fleet.
2.4.5.3 Differences. Ensure personnel understand that compatibility, limits, or restrictions may exist between similar aircraft types with STC conversions, and that the aircraft may have been produced as a freighter by a TC holder.
The following list details examples of the differences:
1. Aircraft weight limits;
2. Cargo zone index changes (forward/aft body);
3. CG limits;
4. Forward and aft body structure loading limits;
5. Fuel index tables;
6. Individual compartment maximum loads;
7. Lateral cargo unbalances;
8. Main deck door opening variances;
9. Maximum allowable loads limited by restraint;
10. Maximum allowable weight limits (takeoff, landing, zero fuel, etc);
11. Maximum area load limits;
12. Maximum cargo zone load limits, including cumulative loads above and below deck;
13. Maximum cumulative load limits;
14. Maximum floor loading limits;
15. Maximum ramp weight limits;
16. Maximum ULD gross weight restrictions by aircraft position;
17. Mi ssing inoperative cargo restraint limits;
18. Reduced overwing zone capabilities;
19. ULD height restrictions;
20. Asymmetrical load limits; and
21. Zero fuel weight restrictions.
2.4.5.4 ULD Contour and Dimensions. Compare the size of the main and lower deck compartment door openings with the contour and dimensions of ULDs to be loaded. An operator must take into consideration any height restriction
2-15 within the aircraft cargo compartments if it is an operating limitation in the WBM (per § 91.9).
2.4.5.5 Approved ULD Limitations. Ensure approved ULD limitations are maintained in the manual. An operator should base these limitations on data from applicable aircraft WBMs or STC supplemental WBMs. The limitations should identify which ULDs are compatible with specific aircraft, and should be easily accessible by all responsible persons.
Note: The limitations section of the AFM or AFM supplement may include information from the aircraft WBM.
2.4.5.6 Authorized ULDs. Ensure the aircraft operator’s WBM states which ULDs may be carried aboard the aircraft on the main deck or lower lobes. In certain instances, particularly with an aircraft’s lower lobes, certain compartments ay be approved to carry bulk or restrained cargo, or both. The WBM should identify the ULDs by the type authorized to be carried aboard the aircraft, considering the aircraft and CLS capabilities.
2.4.5.7 Use of Noncertified ULDs. Ensure the operator does not use noncertified ULDs in any compartment of an all-cargo or combination aircraft, unless:
1. The ULDs are authorized by the WBM, or
2. Tiedown instructions describe how to restrain the ULDs as special cargo.
2.4.5.8 Un authorized Pallet and Net Combinations. Ensure employees and vendors do not combine unapproved nets and pallets.
2.4.6 Responsibilities for Maintenance and Repair of ULDs, Pallets, and Nets If Operator Owned (per §§ 121.363 and 135.413). Operators should maintain ULDs, pallets, and nets using a program based on component maintenance manual (CMM) requirements for TSO’d items. The operator should have a program to determine the serviceability of ULDs before they may be placed on board the aircraft. If an operator repairs these items, it should (1) do so per the CMM of the item, and (2) approve the item for return to service per its procedures authorized by its operations specifications (OpSpecs).
2.4.7 Responsibilities of an Operator for ULDs.
2.4.7.1 Receiving a ULD. When receiving a ULD, an operator who owns or leases its ULDs should have trained, qualified, and authorized personnel perform a serviceability check of the ULD using the operator’s procedures. The serviceability check should include processes, instructions, and guidelines to:
1. Check each ULD before it is put into service;
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2. Review the documentation for new and repaired ULDs, or make the documentation for new and repaired ULDs available upon request, to ensure the ULD is serviceable; and
3. Conduct a visual inspection of the ULD.
Note: The operator may designate a trained, authorized, and qualified person to conduct the checks.
2.4.7.2 Maintaining ULD Repair Records. Certified ULDs should be maintained to the TSO. Noncertified ULDs should be maintained to standard practices or the ULD manufacturer’s directions. The operator should ensure that a repair facility retains the records of those repairs. If an operator maintains its own ULDs, repair records retention should be in accordance with its accepted procedures authorized by OpSpecs issuance. An operator who maintains its own ULDs may maintain its own records or have repair vendors maintain the records, provided the operator can access them upon request within a reasonable period of time.
2.4.7.3 Procedures for Maintaining and Repairing ULDs. An operator that maintains its own certified and noncertified ULDs should have procedures in place to maintain those ULDs in accordance with CMMs and manufacturers’ instructions. If the operator marks its owned certified and noncertified ULD as complying with a TSO, then the operator should ensure that the ULD is maintained per the latest version of that TSO. The procedures should be the same for both certified and noncertified ULDs. The procedures should:
1. Clearly state the data supporting the maintenance and repair; and
2. Address how frequently the operator, ow ner, or repair vendor should check ULD tare weights and how updated ULD tare weights should be marked. The operator or owner should manage control of ULD tare weights by documenting them and retaining the documentation using operator or owner procedures.
2.4.7.4 Guidance for Repairing ULDs. An operator or owner should have procedures to ensure that:
1. Personnel who repair ULDs are trained, qualified, and authorized;
2. ULDs are repaired per the operator’s or owner’s maintenance program for ULDs;
3. The appropriate current data is available to repair the ULD, including operator or owner maintenance manuals, noncertified ULD manufacturer maintenance manuals, SBs, ADs, or certified ULD manufacturer CMMs;
4. The tare weight of each ULD is checked using the operator’s procedures;