Chapter 3 Definitions Goals and Objectives Maintenance Defined

Chapter 3 Definitions, Goals, and Objectives

Maintenance Defined • Airline: • “Those actions required for restoring or maintaining an item in a serviceable condition, • Including servicing, repair, modification, overhaul, inspection, and determination of condition”

Maintenance Defined • Moubray – Industrial consultant • “Ensuring that physical assets continue to do what their users want them to do” • FAA • “Inspection, overhaul, repair, preservation, and replacement of parts” • Hessberg – Chief mechanic – Boeing 777 • “Action necessary to sustain or restore the integrity and performance of the airplane • Includes inspection, overhaul, repair, preservation, and replacement parts”

Maintenance Defined • Kinnison • “Process of ensuring that a system continually performs its intended function at its designed-in level of reliability and safety” • Definition implies servicing, adjusting, replacement, restoration, overhaul, and anything else needed to ensure proper and continual operations of the system or equipment

Inherent Reliability – Degree of reliability depends on: • Design characteristics • Process used for determining maintenance requirements – Inherent reliability is not • The length of time an item will survive with no failures – Inherent reliability is • Level of reliability the item will exhibit when it is protected by preventative maintenance and adequate servicing and lubrication

Aviation Word Pairs • Verification/Validation – Verification • Written test/procedure • When read and understood by a knowledgeable person • Is correct, adequate, and acceptable for the purpose for which it was intended – Validation • Written test/procedure has been performed • By an appropriate trained maintenance person • Understandable, adequate, and proven to accomplish the intended purpose

Aviation Word Pairs • Operational check/Functional check – Operational check • “Task to determine if an item is fulfilling its intended purpose” – Operate equipment, system, or component as usual – Determine whether or not it is useable for its intended purpose – Functional check • “Quantitative check to determine if each function of an item performs within specified limits” – Equipment, system, or component has been checked – Using necessary equipment/tools to measure certain parameters for accuracy

Aviation Word Pairs • Functional failure/Potential failure – Functional failure • “Inability of an item to meet a specific performance standard” – Potential failure • “Detectable condition which shows a functional failure is imminent or could happen very soon”

Aviation Word Pairs • Goals/Objectives – Goals • “Point in time or space where you want a level of accomplishment” – Objectives • “Action or activity you employ to achieve a specific goal”

Airline Maintenance Goals • Airline purpose – Move people/goods from one place to another – (For profit) • Maintenance organization – Support the unit’s operation – “Deliver airworthy vehicles to the flight department in time to meet the flight schedule” – “Deliver these vehicles with all necessary maintenance actions completed or properly deferred”

Airline Maintenance Goals • FAA – Requires maintenance to be done at specified intervals and to accepted standards • Deferrals – Lack of parts, time constraints, etc – In accordance with MEL – No further extension can be granted

Maintenance Program Content • Manual – 2 groups of tasks • Scheduled tasks – Accomplished at specified intervals • Non-scheduled tasks – Conducted after scheduled tasks – Reports of malfunctions – Data analysis – Efficient program • Schedule only tasks necessary to meet stated objectives • Do not schedule additional tasks – Increases costs without reliability increase

Maintenance Objectives • 4 objectives identified by ATA – Developed during initial maintenance program with a new airplane model – Book adds additional objective

Maintenance Objectives • Objective 1 – Ensure the realization of the inherent safety and reliability levels of the equipment • Scheduled maintenance tasks • Developed by – – Equipment manufacturer Airline maintenance organization Third-party maintenance company Industry-supported organization

Maintenance Objectives • Objective 2 – Restore safety and reliability to their inherent levels when deterioration has occurred • Unscheduled maintenance tasks – Troubleshooting actions – Removal/replacement of parts/components – Performance of tests/adjustments • Developed by – MSG process – Contained in manufacturer’s maintenance manual

Maintenance Objectives • Objective 3 – Obtain the information necessary for adjustment and optimization of the maintenance program when these inherent levels are not met • Operator adjusts/optimizes program – – – Investigates if failure/removal rates too high Quality of maintenance performed Inferiority of parts/components Inadequacy of maintenance processes/procedures Maintenance intervals inadequate

Maintenance Objectives • Objective 4 – Obtain the information necessary for design improvement of those items whose inherent reliability proves inadequate • Cannot achieve desired level of reliability – Deficiency in design – Coordinate with other operators/manufacturers – Could be joint effort • Result - redesign

Maintenance Objectives • Objective 5 – Accomplish these objectives at a minimum total cost, including costs of maintenance and the cost or residual failures • Don’t do more maintenance than required – Meet inherent levels of safety and reliability • Cost of modifications too high – May not be justified unless – Measureable increases in performance justify the cost