Eventually all mechanical components or equipments will fail the whole purpose then of maintenance is to not only recognize this fact but to cope with it in the most effective way.
The essential purpose of Aircraft Maintenance is to either return a defective system or component to serviceability or to maintain the aircraft system, component or structure in an airworthy condition.
The primary reasons for aircraft maintenance could be considered to be the following:
a) To keep the aircraft in a serviceable and reliable condition so that may continue to serve its useful purpose.
b) To ensure that all regulatory requirements remain fully in compliance within the concept of delivering continuing airworthiness.
c) To ensure that the asset value is protected.
Maintenance has come a long way since the early days when maintenance programs owed more to the perception of the maintenance needs, as opposed to the analyzed and justified needs.
In addition the role of the regulator was also minimal, and in part developed as a result of events, incidents and accidents.
During the end of the first half of the 20th century regulations began to strengthen and the aircraft manufacturer was seen as the appropriate source of the maintenance program development.
The early attempts at effective maintenance (in the 1960’s) saw time limits developed which resulted in aircraft being progressively dismantled, in what became know as Hard Time primary maintenance.
All hard time components were then routed through an overhaul process and after an appropriate restoration process were considered as zero timed.(means they were considered as zero life and good to go again).
Following investigations into the effectiveness of the Aircraft Maintenance Process, by both the FAA and several airlines, a number of determinations were made.
The first was that in reality schedule overhaul did not have a particular impart on the reliability of a component – unless there was a dominant failure mode evident (Thus calling into question the associated rational in performing the overhaul).
There are many items for which there is no effective maintenance activity for scheduled hard time maintenance.
An outcome of this understanding (of the effectiveness of the maintenance process) was the development of a secondary primary maintenance process, which we know today as On condition maintenance “OC”.
With On Condition Maintenance we ensure that the component or system is maintaining conformity with the expected behaviour (a standard) and any deviation will be the trigger to remover the component from service.
1968 Saw the introduction the Air Transport Association (ATA) Maintenance Steering Group (MSG), logic process for the B747-100 which became known as MSG 1 and consisted of both hard time and on condition processes.
Sofema Aviation Services offer Training courses in Aircraft Production Planning, Maintenance Planning & Reliability. For details please visit www.sassofia.com or email office@sassofia.com
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Aircraft Maintenance, Regulatory training, aviation services
