M.A.401 Maintenance data

 Regulation (EU) 2021/700

(a) The person or organisation maintaining an aircraft shall have access to and use only applicable current maintenance data in the performance of maintenance including modifications and repairs.

(b) For the purposes of this Annex, applicable maintenance data is any of the following:

1.  any applicable requirement, procedure, standard or information issued by the competent authority or the Agency;

2. any applicable airworthiness directive;

3. the applicable instructions for continuing airworthiness and other maintenance instructions, issued by the type-certificate holder, supplementary type-certificate holder and any other organisation that publishes such data in accordance with Annex I (Part 21) to Regulation (EU) No 748/2012;

4. for components approved for installation by the design approval holder, the applicable maintenance instructions published by the component manufacturers and acceptable to the design approval holder;

5. any applicable data issued in accordance with point 145.A.45(d).

(c) The person or organisation maintaining an aircraft shall ensure that all applicable maintenance data is current and readily available for use when required. The person or organisation shall establish a work card or worksheet system to be used and shall either transcribe accurately the maintenance data onto such work cards or worksheets or make precise reference to the particular maintenance task or tasks contained in such maintenance data.

GM1 M.A.401(b)(3) and (b)(4) Maintenance data

ED Decision 2021/009/R

(a) The maintenance data referred to in M.A.401(b)(3) and (4) may have been prepared by various organisations, but in any case it needs to be issued by, referenced by, or acceptable to the organisation responsible for the design in accordance with Part 21 (e.g. type certificate holder (TCH), supplemental type certificate holder (STCH), ETSO holder, repair design approval holder).

(b) Depending on the product or component subject to maintenance and depending on how this maintenance is released, different maintenance data may be needed during the performance of maintenance.

(c) With respect to aircraft maintenance, applicable maintenance data typically includes the following documents issued by the aircraft TCH or the design approval holder (DAH): manufacturer recommended maintenance programme (e.g. MPD, MRBR), aircraft maintenance manual including the airworthiness limitations section, repair manual, supplemental structural inspection document, corrosion prevention and/or control document, service bulletins, wiring diagram manuals, troubleshooting manual, service letter/instructions, illustrated parts catalogue, and any other specific maintenance instruction issued by the aircraft TCH or by the DAH.

(d) With respect to engine maintenance, applicable maintenance data typically includes the engine maintenance and/or overhaul manual including the airworthiness limitations section, wiring diagrams, parts catalogue, troubleshooting manual issued by the engine TCH (or aircraft TCH if the engine is certified as part of the aircraft) or by the DAH.

With respect to APU maintenance, applicable maintenance data typically includes APU maintenance and/or overhaul manual, wiring diagrams, parts catalogue, troubleshooting manual issued by the aircraft TCH, or issued by the APU manufacturer and acceptable to the TCH of the aircraft on which it is installed or to the DAH.

When in compliance with M.A.502(b), it is possible to conduct maintenance on the engine or APU while installed on the aircraft or temporarily removed to gain access. In such case, the applicable maintenance data may also include aircraft maintenance data.

(e) With respect to maintenance of components other than engine/APU, applicable maintenance data typically includes the component maintenance (and/or repair) manual, troubleshooting manual and other maintenance instructions produced by the component manufacturer, when they are acceptable to the TCH of the product in which the component is to be installed or to the DAH, or when they form part of (or are referenced together with) the product ICA. In the case of propellers, maintenance data includes its ICA.

When in compliance with M.A.502(b) or M.A.502(c), it is possible to conduct maintenance on the component while installed on the aircraft or engine or APU, or temporarily removed to gain access. In such case, the applicable maintenance data may also include, as applicable, aircraft maintenance data or engine/APU maintenance data.

(f) With respect to maintenance considered to be specialised services (such as non-destructive testing (NDT)), applicable maintenance data typically includes non-destructive testing or inspection manual, and all applicable specialised service(s) process instructions issued or specified by the DAH.

GM1 M.A.401(b)(4) Maintenance data

ED Decision 2021/009/R

COMPONENT MANUFACTURER MAINTENANCE INSTRUCTIONS

The maintenance instructions published by the component manufacturers may be considered acceptable to the DAH – and hence may be used as maintenance data for maintenance on components approved for installation by the DAH – when they are referenced as additional or optional maintenance information together with the ICA, or when documented by a list by that DAH (GM3 21.A.7(a)).

AMC M.A.401(c) Maintenance data

ED Decision 2015/029/R

1. Data being made available to personnel maintaining aircraft means that the data should be available in close proximity to the aircraft or component being maintained, for mechanics and certifying staff to perform maintenance.

2. Where computer systems are used, the number of computer terminals should be sufficient in relation to the size of the work programme to enable easy access, unless the computer system can produce paper copies. Where microfilm or microfiche readers/printers are used, a similar requirement is applicable.

3. Maintenance tasks should be transcribed onto the work cards or worksheets and subdivided into clear stages to ensure a record of the accomplishment of the maintenance task. Of particular importance is the need to differentiate and specify, when relevant, disassembly, accomplishment of task, reassembly and testing. In the case of a lengthy maintenance task involving a succession of personnel to complete such task, it may be necessary to use supplementary work cards or worksheets to indicate what was actually accomplished by each individual person. A worksheet or work card system should refer to particular maintenance tasks.

4. The workcard/worksheet system may take the form of, but is not limited to, the following:

               a format where the mechanic writes the defect and the maintenance action taken together with information of the maintenance data used, including its revision status,

               an aircraft log book that contains the reports of defects and the actions taken by authorised personnel together with information of the maintenance data used, including its revision status,

               for maintenance checks, the checklist issued by the manufacturer (i.e., 100H checklist, Revision 5, Items 1 through 95)

5. Maintenance data should be kept up to date by:

               subscribing to the applicable amendment scheme,

               checking that all amendments are being received,

               monitoring the amendment status of all data.

M.A.402 Performance of maintenance

Regulation (EU) 2015/1536

Except for maintenance performed by a maintenance organisation approved in accordance with Annex II (Part-145), any person or organisation performing maintenance shall:

(a) be qualified for the tasks performed, as required by this part;

(b) ensure that the area in which maintenance is carried out is well organised and clean in respect of dirt and contamination;

(c) use the methods, techniques, standards and instructions specified in the M.A.401 maintenance data;

(d) use the tools, equipment and material specified in the M.A.401 maintenance data. If necessary, tools and equipment shall be controlled and calibrated to an officially recognised standard;

(e) ensure that maintenance is performed within any environmental limitations specified in the M.A.401 maintenance data;

(f) ensure that proper facilities are used in case of inclement weather or lengthy maintenance;

(g) ensure that the risk of multiple errors during maintenance and the risk of errors being repeated in identical maintenance tasks are minimised;

(h) ensure that an error capturing method is implemented after the performance of any critical maintenance task; and

(i) carry out a general verification after completion of maintenance to ensure the aircraft or component is clear of all tools, equipment and any extraneous parts or material, and that all access panels removed have been refitted.

AMC M.A.402(a) Performance of maintenance

ED Decision 2016/011/R

1. Maintenance should be performed by persons authorised to issue a certificate of release to service or under the supervision of persons authorised to issue a certificate of release to service. Supervision should be to the extent necessary to ensure that the work is performed properly and the supervisor should be readily available for consultation.

2. The person authorised to issue a certificate of release to service should ensure that:

(a) each person working under his/her supervision has received appropriate training or has relevant previous experience and is capable of performing the required task; and

(b) each person who performs specialised tasks, such as welding, is qualified in accordance to an officially recognised standard.

GM M.A.402(a) Performance of maintenance

ED Decision 2016/011/R

In the case of limited Pilot-owner maintenance, as specified in M.A.803, any person maintaining an aircraft which they own individually or jointly, provided they hold a valid pilot licence with the appropriate type or class rating, may perform the limited Pilot-owner maintenance tasks in accordance with Appendix VIII to Annex I (Part-M) to Regulation (EU) No 1321/2014.

AMC M.A.402(c) Performance of maintenance

ED Decision 2016/011/R

The general maintenance and inspection standards applied to individual maintenance tasks should meet the recommended standards and practices of the organisation responsible for the type design, which are normally published in maintenance manuals. In the absence of maintenance and inspection standards published by the organisation responsible for the type design, maintenance personnel should refer to the relevant aircraft airworthiness standards and procedures published or used as guidance by the Agency or the competent authority. The maintenance standards used should contain methods, techniques and practices acceptable to the Agency or the competent authority for the maintenance of aircraft and its components.

AMC M.A.402(d) Performance of maintenance

ED Decision 2016/011/R

When performing maintenance, personnel are required to use the tools, equipment and test apparatuses necessary to ensure completion of work in accordance with accepted maintenance and inspection standards. Inspection, service or calibration that is performed on a regular basis should be performed in accordance with the equipment manufacturers’ instructions. All tools requiring calibration should be traceable to an acceptable standard. 

In this context, ‘officially recognised standards’ means those standards established or published by an official body, being either a natural or legal person, and which are widely recognised by the air transport sector as constituting good practice.

If the organisation responsible for the type design involved recommends special equipment or test apparatuses, personnel should use the recommended equipment or apparatuses or equivalent equipment accepted by the competent authority.

All work should be performed using materials of such quality and in such a manner that the condition of the aircraft or its components after maintenance is at least equal to its or their original or modified condition (with regard to aerodynamic function, structural strength, resistance to vibration, deterioration and any other qualities affecting airworthiness).

AMC M.A.402(e) Performance of maintenance

ED Decision 2016/011/R

The working environment should be appropriate for the maintenance task being performed such that the effectiveness of personnel is not impaired.

(a) Temperature should be maintained such that personnel can perform the required tasks without undue discomfort.

(b) Airborne contamination (e.g. dust, precipitation, paint particles, filings) should be kept to a minimum to ensure aircraft/components surfaces are not contaminated, if this is not possible all susceptible systems should be sealed until acceptable conditions are re-established.

(c) Lighting should be adequate to ensure each inspection and maintenance task can be performed effectively.

(d) Noise levels should not be allowed to rise to the level of distraction for inspection staff or if this is not possible inspection staff should be provided with personnel equipment to reduce excessive noise.

AMC M.A.402(f) Performance of maintenance

ED Decision 2016/011/R

Facilities should be provided appropriate for all planned maintenance. This may require aircraft hangars that are both available and large enough for the planned maintenance.

Aircraft component workshops should be large enough to accommodate the components that are planned to be maintained.

Protection from inclement weather means the hangar or component workshop structures should be to a standard that prevents the ingress of rain, hail, ice, snow, wind and dust etc.

AMC M.A.402(g) Performance of maintenance

ED Decision 2016/011/R

(a) To minimise the risk of multiple errors and to prevent omissions, the person or organisation performing maintenance should ensure that:

(1) every maintenance task is signed off only after completion;

(2) the grouping of tasks for the purpose of sign-off allows critical steps to be clearly identified; and

(3) any work performed by personnel under supervision (i.e. temporary staff, trainees) is checked and signed off by an authorised person.

(b) To minimise the possibility of an error being repeated in identical tasks that involve removal/installation or assembly/disassembly of several components of the same type fitted to more than one system, whose failure could have an impact on safety, the person or organisation performing maintenance should plan different persons to perform identical tasks in different systems. However, when only one person is available, then this person should perform reinspection of the tasks as described in AMC2 M.A.402(h).

CRITICAL MAINTENANCE TASKS

The following maintenance tasks should primarily be reviewed to assess their impact on safety:

(a) tasks that may affect the control of the aircraft, flight path and attitude, such as installation, rigging and adjustments of flight controls;

(b) aircraft stability control systems (autopilot, fuel transfer);

(c) tasks that may affect the propulsive force of the aircraft, including installation of aircraft engines, propellers and rotors; and

(d) overhaul, calibration or rigging of engines, propellers, transmissions and gearboxes.

INDEPENDENT INSPECTION

(a) What is an independent inspection

Independent inspection is one possible error-capturing method. It consists of an inspection performed by an ‘independent qualified person’ of a task carried out by an ‘authorised person’, taking into account that:

(1) the ‘authorised person’ is the person who performs the task or supervises the task and assumes the full responsibility for the completion of the task in accordance with the applicable maintenance data;

(2) the ‘independent qualified person’ is the person who performs the independent inspection and attests the satisfactory completion of the task and that no deficiencies have been found. The ‘independent qualified person’ does not issue a certificate of release to service, therefore he/she is not required to hold certification privileges;

(3) the certificate of release to service is issued by the ‘authorised person’ after the independent inspection has been carried out satisfactorily;

(4) the work card system should record the identification of each person, the date and the details of the independent inspection, as necessary, before the certificate of release to service is issued.

(b) Qualifications of personnel performing independent inspections

(1) When the work is performed by a Part-M Subpart F organisation, then the organisation should have procedures to demonstrate that the ‘independent qualified person’ has been trained and has gained experience in the specific control systems to be inspected. This training and experience could be demonstrated, for example, by:

(i) holding a Part-66 licence in the same subcategory as the licence subcategory or equivalent necessary to release or sign off the critical maintenance task;

(ii) holding a Part-66 licence in the same category and specific training in the task to be inspected; or

(iii) having received appropriate training and having gained relevant experience in the specific task to be inspected.

(2) When the work is performed outside a Part-M Subpart F organisation:

(i) the ‘independent qualified person’ should hold:

(A) a Part-66 licence in any category or an equivalent national qualification when national regulations apply; or

(B) a valid pilot licence for the aircraft type issued in accordance with European Union regulations or an equivalent national qualification when national regulations apply;

(ii) additionally, the ‘authorised person’ should assess the qualifications and experience of the ‘independent qualified person’ taking into account that the ‘independent qualified person’ should have received training and have experience in the particular task. It should not be acceptable that the ‘authorised person’ shows to the ‘independent qualified person’ how to perform the inspection once work has been already finalised.

(c) How should independent inspection be performed

Independent inspection should ensure for example correct assembly, locking and sense of operation. When inspecting control systems that have undergone maintenance, the ‘independent qualified person’ should consider the following points independently:

(1) all those parts of the system that have actually been disconnected or disturbed should be inspected for correct assembly and locking;

(2) the system as a whole should be inspected for full and free movement over the complete range;

(3) cables should be tensioned correctly with adequate clearance at secondary stops;

(4) the operation of the control system as a whole should be observed to ensure that the controls are operating in the correct sense;

(5) if different control systems are interconnected so that they affect each other, all the interactions should be checked through the full range of the applicable controls; and

(6) software that is part of the critical maintenance task should be checked, for example version and compatibility with the aircraft configuration.

(d) What to do in unforeseen cases when only one person is available

REINSPECTION:

(1) Reinspection is subject to the same conditions as the independent inspection is, except that the ‘authorised person’ performing the maintenance task is also acting as ‘independent qualified person’ and performs the inspection.

(2) For critical maintenance tasks, reinspection should only be used in unforeseen circumstances when only one person is available to carry out the task and perform the independent inspection. The circumstances cannot be considered unforeseen if the person or organisation has not assigned a suitable ‘independent qualified person’ to that particular task.

(3) The certificate of release to service is issued by the ‘authorised person’ after the reinspection has been performed satisfactorily.

(4) The work card system should record the identification of the ‘authorised person’ and the date and the details of the reinspection, as necessary, before the certificate of release to service is issued.

GM M.A.402(h) Performance of maintenance

ED Decision 2016/011/R

Several data sources may be used for the identification of critical maintenance tasks, such as:

               information from the design approval holder;

               accident reports;

               investigation and follow-up of incidents;

               occurrence reporting;

               flight data analysis;

               results of audits;

               normal operations monitoring schemes;

               feedback from training; and

               information exchange systems.

M.A.403 Aircraft defects

Regulation (EU) 2021/1963

(a) Any aircraft defect that hazards seriously the flight safety shall be rectified before further flight.

(b) Only the certifying staff referred to in point M.A.801(b)(1) or in Subpart F of this Annex or in Annex II (Part-145) or in Annex Vd (Part-CAO), or the person authorised in accordance with point M.A.801(c) of this Annex can decide, using maintenance data referred to in point M.A.401 of this Annex, whether an aircraft defect hazards seriously the flight safety and therefore decide when and which rectification action shall be taken before further flight and which defect rectification can be deferred. However, this does not apply when the MEL is used by the pilot or by the certifying staff.

(c) Any aircraft defect that would not hazard seriously the flight safety shall be rectified as soon as practicable, after the date the aircraft defect was first identified and within any limits specified in the maintenance data or the MEL.

(d) Any defect not rectified before flight shall be recorded in the aircraft continuing airworthiness record system referred to in point M.A.305 or, if applicable in the aircraft technical log system referred to in point M.A.306.

AMC M.A.403(b) Aircraft defects

ED Decision 2015/029/R

An assessment of both the cause and any potentially hazardous effect of any defect or combination of defects that could affect flight safety should be made in order to initiate any necessary further investigation and analysis necessary to identify the root cause of the defect.

AMC M.A.403(d) Aircraft defects

ED Decision 2015/029/R

All deferred defects should be made known to the pilot/flight crew, whenever possible, prior to their arrival at the aircraft.

Deferred defects should be transferred on to worksheets at the next appropriate maintenance check, and any deferred defect which is not rectified during the maintenance check, should be re-entered on to a new deferred defect record sheet. The original date of the defect should be retained.

The necessary components or parts needed for the rectification of defects should be made available or ordered on a priority basis, and fitted at the earliest opportunity.