M.A.402 Performance of maintenance

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.

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.

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.

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).

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.

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.

(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.

Several data sources may be used for the identification of critical maintenance tasks, such as: information from the design approval holder or the declarant of a declaration of design compliance; 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.