The strategic maintenance-management layer of the AGL Asset Lifecycle Guide. Division 09 decides what maintenance strategy should be used, why it should be used, when it should be reviewed, and how its effectiveness should be evaluated — while the AGL Maintenance Handbook defines how each maintenance task is actually performed.
The question this division answers — Given everything we know about how each AGL asset is actually performing and failing, what maintenance strategy should we apply, on which asset, at what frequency, using what resources — and how do we prove it is working?
Division 07 establishes baseline asset performance and Division 08 tracks how assets actually perform in operation. Division 09 is where that evidence is converted into a deliberate maintenance strategy — before it is handed to the AGL Maintenance Handbook for execution.
Every AGL asset should have an appropriate maintenance strategy, selected deliberately rather than applied uniformly across all assets.
Do not automatically apply the same maintenance strategy to every asset — the strategy should follow evidence, not habit.
Preventive maintenance is planned maintenance intended to reduce the probability of failure or maintain the asset in an acceptable condition.
Fixture inspection, CCR inspection, transformer inspection, cable-system testing, PAPI inspection, sign inspection, earthing inspection, control-system checks.
The specific inspection/test procedure for each of these should remain in the AGL Maintenance Handbook.
Predictive maintenance uses measured condition/performance information to anticipate deterioration or failure before it happens.
Particularly valuable where deterioration can be detected before functional failure occurs.
Condition-based maintenance bases intervention decisions on the actual condition of the asset, rather than relying solely on a fixed calendar interval.
This should be linked directly with Division 07 baseline data and Division 08 operational trends.
Corrective maintenance addresses a detected defect, deterioration or failure.
Priority, response requirement, escalation, resource requirement, spare requirement, restoration objective, root-cause review requirement.
The detailed repair procedure remains in the AGL Maintenance Handbook.
Risk-based maintenance prioritizes maintenance according to the consequence and likelihood of failure. It connects directly to Division 03 — Asset Criticality & Risk Assessment.
A highly critical runway lighting asset may receive greater maintenance attention than a lower-consequence asset, even if both have similar physical condition.
Maintenance optimization seeks the best balance between reliability, safety, availability, resources and cost.
Not "do maximum maintenance." Not "do minimum maintenance." The objective is: do the right maintenance at the right time on the right asset.
Maintenance frequency should be based on evidence, rather than automatically repeating historical schedules forever.
Is the current maintenance interval preventing failures effectively without creating unnecessary maintenance effort?
Increase frequency if deterioration is occurring earlier than expected. Reduce frequency if condition remains stable and risk remains acceptable. Change strategy from preventive to condition-based/predictive where sufficient data exists.
Individual maintenance tasks should also be reviewed on their own merits, not just the overall strategy.
Every recurring maintenance task should have a defined lifecycle purpose.
Maintenance strategy must consider the resources required to execute it — a strategy that cannot be resourced is not a real strategy.
Ensure that the selected maintenance strategy is actually executable, not just theoretically correct.
Work orders convert maintenance strategy into controlled maintenance activities. The Asset Lifecycle Guide establishes the management logic; the Maintenance Handbook can define the detailed workflow.
A maintenance backlog represents work that has been identified but has not yet been completed.
A backlog should not simply be managed by age of work order. A newer critical safety-related task may require higher priority than an older low-risk task.
Critical, High, Medium, Low, Planned, Deferred with justification.
Maintenance effectiveness measures whether the maintenance strategy is actually achieving its intended purpose.
Did the maintenance activity improve or preserve asset performance? A maintenance activity should not automatically be considered effective merely because the work order was closed.
Maintenance cost should be analyzed as part of lifecycle decision-making, not tracked in isolation from asset performance.
Compare preventive cost vs. failure cost vs. downtime consequence — this helps determine whether maintenance strategy is economically justified.
Maintenance strategy should not remain unchanged for the entire asset life — it should be periodically reviewed using actual lifecycle evidence.
Continue current strategy, modify maintenance frequency, change maintenance type, increase monitoring, reduce unnecessary maintenance, refurbish, or replace.
A strategic decision model for selecting maintenance strategy asset-by-asset, working from criticality down to demonstrated preventive-maintenance effectiveness.
| Step | Question | If Yes | If No |
|---|---|---|---|
| 1 | Is the asset safety/operationally critical? | Higher maintenance control | Continue risk assessment |
| 2 | Does failure have significant consequences? | Risk-based maintenance | Continue assessment |
| 3 | Is deterioration measurable? | Condition-based / predictive strategy | Preventive / corrective strategy as appropriate |
| 4 | Is failure predictable? | Predictive intervention | Preventive / condition-based / corrective, based on risk |
| 5 | Is preventive maintenance demonstrably effective? | Continue and optimize interval | Review task/strategy |
A strategic framework, not a universal maintenance prescription. Actual strategy should be determined from the airport's approved risk methodology and asset-specific evidence.
| Asset Condition / Risk | Recommended Strategy |
|---|---|
| Critical + high failure consequence | Risk-based + preventive/condition monitoring |
| Critical + measurable deterioration | Condition-based / predictive |
| Critical + unpredictable failure | Preventive + contingency planning |
| Medium criticality + measurable condition | Condition-based |
| Medium criticality + predictable deterioration | Preventive |
| Low criticality + low consequence | Corrective / optimized preventive |
| Repeated failure | Reliability investigation + strategy review |
| Obsolete asset | Renewal/replacement strategy |
This separation is very important — Division 09 should not duplicate the detailed maintenance procedures already contained in the AGL Maintenance Handbook. Instead, it establishes the strategic decision framework that governs those procedures.
The 15 topics kept exactly as the maintenance-strategy structure, each mapped to the primary question it answers.
| No. | Topic | Primary Question |
|---|---|---|
| 01 | Maintenance Strategy Selection | What strategy fits this asset's risk and behaviour? |
| 02 | Preventive-Maintenance Strategy | What planned maintenance reduces failure probability? |
| 03 | Predictive-Maintenance Strategy | Can deterioration be anticipated from trend data? |
| 04 | Condition-Based Maintenance | Does actual condition justify intervention now? |
| 05 | Corrective-Maintenance Strategy | How should a detected defect be addressed? |
| 06 | Risk-Based Maintenance | Where should limited maintenance attention go first? |
| 07 | Maintenance Optimization | Is this the right maintenance at the right time? |
| 08 | Maintenance Frequency Optimization | Is the current interval still justified by evidence? |
| 09 | Maintenance Task Optimization | Does every recurring task still earn its place? |
| 10 | Maintenance-Resource Planning | Can this strategy actually be executed? |
| 11 | Work-Order Strategy | How does strategy become controlled activity? |
| 12 | Maintenance Backlog Management | What order should outstanding work be tackled in? |
| 13 | Maintenance Effectiveness | Is the maintenance actually working? |
| 14 | Maintenance Cost Analysis | Is the maintenance economically justified? |
| 15 | Maintenance Strategy Review | Should the strategy itself now change? |
The recommended formal outputs of Division 09.
Maintenance strategy should be determined by asset risk, failure behaviour, condition, utilization, operational requirements and lifecycle cost — not simply by a fixed calendar schedule.
Division 09 operates as a continuous optimization loop, not a one-time decision:
This is the mechanism by which the handbook evolves from a static maintenance schedule into a data-driven AGL asset-management system — the strategic bridge between asset performance data and the detailed AGL Maintenance Handbook, while keeping the two documents clearly separated: the Lifecycle Guide governs the maintenance strategy; the Maintenance Handbook governs the maintenance procedure.
Quick answers about Maintenance Strategy & Optimization in the AGL Asset Lifecycle Guide.
Division 09 is the strategic bridge between asset performance data and the AGL Maintenance Handbook. It covers 15 topics on maintenance strategy selection, preventive, predictive, condition-based and corrective maintenance, risk-based maintenance, optimization, resource planning, work orders, backlog, effectiveness, cost and strategy review.
Every AGL asset should have an appropriate strategy, selected deliberately rather than applied uniformly across all assets. Selection considers criticality, failure consequence, reliability, condition, utilization and operating environment.
Preventive maintenance is planned work intended to reduce the probability of failure. Predictive maintenance uses measured condition or performance information to anticipate deterioration before it happens. Condition-based maintenance bases intervention on actual condition rather than only a fixed calendar interval. Corrective maintenance addresses a detected defect, deterioration or failure.
Risk-based maintenance prioritizes maintenance according to the consequence and likelihood of failure. It connects directly to Division 03 and considers safety, operational, regulatory and financial consequence.
Maintenance optimization seeks the best balance between reliability, safety, availability, resources and cost. Frequency should be based on evidence rather than repeating historical schedules forever, and each task should be reviewed on its own merits, asking what failure it prevents or detects and whether it is effective.
A strategy that cannot be resourced is not a real strategy. Resource planning considers people, such as engineers, technicians, specialists and contractors, as well as equipment such as test instruments and photometric equipment.
Work orders convert maintenance strategy into controlled maintenance activities. A backlog is work identified but not yet completed, and it should be prioritized using criticality, risk, age, failure consequence, regulatory requirement and operational impact.
Effectiveness measures whether the strategy achieves its purpose using failure frequency, repeat failures, availability, MTBF, MTTR and emergency maintenance. Strategy should not stay unchanged for the whole asset life and is reviewed periodically using actual failure, condition, performance and cost evidence.
Effective AGL asset management starts with choosing the right maintenance strategy for each asset, not applying one approach to everything.
Learn how preventive, predictive, condition-based and risk-based maintenance strategies, and maintenance optimization, connect across the complete AGL asset lifecycle.
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