Learn more about the use of manufacturer’s maintenance instructions and manufacturer’s recommended inspection schedules under the proposed general aviation maintenance regulations (Part 43 of the Civil Aviation Safety Regulations 1998 (CASR)) and the Part 43 Manual of Standards.
Who should read this?
- Registered operators of aircraft to which Part 43 will apply
- CAR30 organisations
- Part 145 approved maintenance organisations
- Licensed aircraft maintenance engineers Definition of terms "other methods, techniques and practices..." and 'a tool the use of which would provide an equivalent maintenance outcome'
Definition of terms "other methods, techniques and practices..." and "a tool the use of which would provide an equivalent maintenance outcome"
The terms "other methods, techniques and practices that a person reasonably considers are consistent with accepted industry methods, techniques and practices for the carrying out of (maintenance of its kind/that kind of maintenance task)" and "if a tool required by the manufacturer's maintenance instructions is not reasonably available — a tool the use of which would provide an equivalent maintenance outcome" are used in the Part 43 Manual of Standards (Part 43 MOS) to provide for the permissible use of non-approved maintenance techniques, if other requirements are satisfied.
Where a MOS provision uses one of these terms, it means that the use of methods, techniques, practices, or tool that are alternate to those required under the manufacturer's maintenance instructions, etc do not require CASA approval provided that the alternate methods etc are "consistent with accepted industry methods, techniques and practices" or, if it is a tool, its use would provide an equivalent maintenance outcome. This can be demonstrated by using methods, practices, tools etc that meet relevant regulatory standards for the kind of maintenance being carried out.
The MOS requires that the person carrying out the maintenance must do so in a way, and use materials of a quality, so that the condition of the aircraft or aeronautical product (e.g. airframe, aircraft engine, or aircraft propeller) worked on will be at least equal to its original or properly altered condition, having regard to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting the airworthiness of the aircraft. CASA may take enforcement action for non-compliance with this requirement.
However, if a person using an alternate method, technique, practice or tool, as mentioned above is able to demonstrate to CASA that the method, technique, practice or tool complies with accepted industry standards for the carrying out of the kind of maintenance or particular maintenance task, the requirement should be met.
In any event, if CASA considers that an alternate method, practice or tool is unacceptable, the maintenance provider/certificate holder will be provided written advice of the potential non-compliance and compliance requested.
What are manufacturer's maintenance instructions?
The Part 43 MOS defines manufacturers' maintenance instructions as follows:
- manufacturer's maintenance instructions means, unless otherwise specified, the maintenance manual, or other document, as it exists from time to time, that is:
- for the maintenance of an aircraft — issued by the manufacturer of the aircraft; and
- for the maintenance of an aeronautical product — issued by the manufacturer of the aeronautical product; and
- sets out instructions for the maintenance task concerned.
Note: Manufacturer's maintenance instructions include instructions for continuing airworthiness that are issued by the manufacturer of the aircraft or aeronautical product, but do not include supplementary instructions that may be issued in service bulletins or similar documents.
Use of manufacturer's recommended inspection schedule
The manufacturer's recommended inspection schedule is also known as the ‘aircraft manufacturer's recommended inspection program' (and is generally found in the ICAs for the aircraft).
Section 4.17 of the draft Part 43 MOS states that if a registered operator elects to adopt the aircraft manufacturer's recommended inspection schedule, they must use the manufacturer's inspection schedule as in force at the time of the election. Once adopted, that schedule remains the "current" schedule for the aircraft until such time as the RO elects to use the latest version of the aircraft manufacturer's inspection schedule instead. If RO elects to use the latest version, the election must be recorded in the maintenance records for the aircraft.
This means that future versions/revisions of the aircraft manufacturer's inspection schedule will not retrospectively affect the RO's chosen inspection schedule unless the RO elects to use the future version/revision.
However, if an airworthiness directive requires use of a particular version of the aircraft manufacturer's recommended inspection schedule, that version must be used.
Note: CASA approval is not required for adoption of an aircraft manufacturer’s recommended inspection schedule. The RO may also elect to use a written inspection schedule that requires use of an inspection checklist based on Schedule 1 of the draft Part 43 MOS, or an inspection schedule proposed by the RO. However, CASA approval would be required for a written inspection schedule proposed by the RO.
Which version of a manufacturer's maintenance instructions for carrying out a maintenance activity is required?
When carrying out maintenance, a maintainer is required to use the latest version of the manufacturer’s maintenance instructions, (which includes Instructions for Continued Airworthiness) in effect at the time of use.
This requirement only applies to the instructions for carrying out a maintenance activity and does not refer to timing of the maintenance action or inspection. The manufacturer's maintenance instructions (sometimes known as the 'manufacturer's maintenance manual') describes the "how", not the "when".
Note: Service bulletins are not considered part of a manufacturer's maintenance manual for this purpose. For more information about service bulletins, refer to the Service Bulletins information sheet.
Useable data for minor repairs or modifications
Useable data for which CASA approval is not required, may be sourced from a wide range of sources. Table 1 sets out a list of useable data sources, however the list is not exhaustive.
Table 1: Useable data
- Type certificate data sheets.
- Foreign type certificate data sheets used for the issue of a type acceptance certificate.
- Type design data for type certificated products – for example, approved drawings issued by the type certificate holder.
- Design change data that support a design change approved under Part 21.
- Data provided by CASA or a recognised authority in an advisory circular or other advisory document.
- Airworthiness directives that give specific instructions for modification or repair.
- Supplemental type certificates or approvals issued by CASA or a recognised foreign NAA.
- Data giving specific instructions for modification or repair contained in a maintenance manual, repair manual, overhaul manual, continuing airworthiness document, service bulletin, or an equivalent provided by the manufacturer of the product for which it is to be used and which is listed in the type certificate or by reference in the type acceptance certificate i.e. data that has been approved for use by the type certificate holder. Note: This includes data provided by the manufacturer of a component of a product where that component is a part of the approved type design of the product.
- Data included in, and specific to the category of, an airworthiness certificate.
- Any data mentioned in Table 2 below.
What is meant by “Approved” in relation to data etc?
The difference between “useable” and “approved” is that if an action, tool, process, or data is required to be approved, it must be assessed by CASA, or an authorised person if allowed under CASR, and written approval obtained.
Regulations 21.305 and 21.305A of CASR set out the requirements for approval of materials, parts, processes, and appliances, but these regulations do not apply to approvals of modifications or repairs.
Approved data for major modifications and major repairs
If a modification or maintenance action requires conformity to approved data, the data must be approved under Subpart 21.M of CASR which sets out the requirements and conditions relating to approvals of modifications and repairs.
Table 2 lists some possible sources for approved data which may be used under the proposed CASR Part 43.
Table 2: Approved data – some possible sources
- Type Certificate Data Sheet (TCDS)
- Repair data from AC 43.13-1, Acceptable Methods, Techniques, and Practices—Aircraft Inspection and Repair
- Modification data from AC 43.13-2, Acceptable Methods, Techniques, and Practices—Aircraft
- Airworthiness Directives (AD)
- Aeronautical product manufacturer’s maintenance instructions, unless specifically not approved by CASA, may be used as approved data for major repairs.
- Data describing an article used in an NAA-approved alteration under a Parts Manufacturer Approval (PMA).
- Authorised person-approved data, including repair specifications, within limitations on the AP’s authorization.
- Approved Design Organisation -approved data, within limitations in the ODA holder’s procedures manual.
- NAA-approved portions of Structural Repair Manuals (SRM).
- NAA -approved Service Bulletins (SB) and Service Letters (SL) or similar documents.
- Foreign bulletins, for use on Australian-certificated foreign-designed aircraft, when approved by the foreign authority within the provisions of a bilateral agreement with Australia or as listed in TCDS notes.
- Supplemental Type Certificate (STC) data may substantiate a major alteration on a different aircraft, provided such alteration is applicable to specifically listed make, model, and type appropriate to the certification basis and applicable amendments.
The content provided in the information sheet is a guide only as to how the rules may work in practice once Part 43 of CASR and the Part 43 Manual of Standards is made and commence.