CAO.A.060 Maintenance standards

(a)To minimise the risk of errors and to prevent omissions, the approved CAO when 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 approved CAO when 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 CAO.A.060(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’s flight path and attitude, such as the installation, rigging and adjustments of flight controls;

(b)tasks that may affect aircraft stability control systems (autopilots, fuel transfer);

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

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

INDEPENDENT INSPECTION Independent inspection is one possible error-capturing method.

(a)What is an independent inspection An independent inspection is an inspection, which is 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 to 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 (CRS); therefore, he or she is not required to hold certification privileges;

(3)the CRS is issued by the ‘authorised person’ after the independent inspection has been carried out satisfactorily; and

(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 CRS is issued.

(b)Qualifications of personnel performing independent inspections 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; or

(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.

(c)How to perform an independent inspection The independent inspection should ensure, for example, the correct assembly, locking and sense of operation of the parts involved. 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 their 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 operate 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, its version and its 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 to be unforeseen if the person or organisation has not assigned a suitable ‘independent qualified person’ to that particular task.

(3)The CRS 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 CRS is issued.