The risk-decision layer of the AGL Asset Lifecycle Guide. Division 01 establishes the asset strategy and Division 02 establishes the asset data foundation — Division 03 determines which assets matter most, what can happen if they fail, how likely failure is, and where management and maintenance resources should be prioritized.
The question this division answers — Which AGL assets matter most, what happens if each one fails, how likely is that failure, and where should management and maintenance resources be prioritized as a result?
Division 03 is the bridge between the asset data established in Division 02 and the later lifecycle decisions covering maintenance, asset health, reliability, lifecycle cost, refurbishment, replacement and digital asset management.
Establishes a consistent method for determining the importance of each AGL asset. The methodology should avoid assigning criticality simply because an asset is expensive or technically complex.
The exact scoring methodology should be formally approved by the airport/asset-management organization.
Converts the criticality assessment into an understandable priority level. The actual rating thresholds should be established through the approved airport risk methodology.
| Rank | Criticality | General Meaning |
|---|---|---|
| 1 | Very Low | Minimal consequence |
| 2 | Low | Limited consequence |
| 3 | Medium | Significant but manageable |
| 4 | High | Major operational/safety consequence |
| 5 | Critical | Severe consequence requiring highest control |
Safety-critical assets are assets where failure can have a significant effect on aviation safety — identified as a separate criticality category.
Classification should be based on the airport's approved risk assessment — not on automatically treating every item of a particular equipment type as equally critical.
Operational criticality measures the effect of asset failure on airport operational continuity.
A CCR supplying an entire critical runway circuit may have significantly greater operational criticality than a single non-critical auxiliary component.
Runway assets require dedicated criticality assessment because their failure may affect runway operations and aircraft guidance.
Criticality should consider the function and system context, not merely the equipment type.
Evaluates the consequence of failure of taxiway lighting and associated equipment.
PAPI criticality assesses the importance of the PAPI system to aircraft approach guidance — identified as an individual assessment category.
The criticality assessment can distinguish between:
CCR criticality should consider the AGL circuit or circuits supplied by the regulator. A CCR may be highly critical because one equipment failure can affect multiple field assets simultaneously.
A CCR supplying a critical runway lighting circuit may receive a higher criticality rating than a CCR serving a less operationally significant area.
Refers particularly to isolating transformers within the AGL series circuit.
The criticality of a transformer should be evaluated based on the function it supports, not only its purchase value.
Evaluates the consequence of primary/secondary cable failure.
A primary series-circuit cable supplying a major runway circuit can have much higher criticality than a short secondary connection serving an individual fixture.
Airfield-sign criticality should consider the operational function of the sign.
Potentially different criticality categories could apply to: runway designation signs, mandatory instruction signs, location signs, direction signs, and taxiway guidance signs. The assessment should be based on actual airport operational context.
ALCMS criticality should consider the system's role in controlling and monitoring AGL — identified as its own category within Division 03.
Each component can have its own asset record and criticality.
Failure consequence assessment asks: what happens if this asset fails? This is one of the most important steps in the risk process.
Probability of failure estimates how likely an asset is to fail within a defined period.
| Score | Probability |
|---|---|
| 1 | Rare |
| 2 | Unlikely |
| 3 | Possible |
| 4 | Likely |
| 5 | Almost Certain |
The actual definitions should be established by the approved risk methodology.
The risk matrix combines probability of failure with consequence of failure.
| Prob ↓ / Cons → | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| 1 | 1 | 2 | 3 | 4 | 5 |
| 2 | 2 | 4 | 6 | 8 | 10 |
| 3 | 3 | 6 | 9 | 12 | 15 |
| 4 | 4 | 8 | 12 | 16 | 20 |
| 5 | 5 | 10 | 15 | 20 | 25 |
The airport should define which numerical ranges correspond to low, medium, high or critical risk. This is an illustrative structure, not a risk matrix mandated by any single standard — it should be formally adopted at organizational level.
Risk ranking establishes the relative priority of assets. The highest-risk assets should receive greater management attention.
| Asset | Probability | Consequence | Risk |
|---|---|---|---|
| CCR-01 | 4 | 5 | 20 |
| PAPI-01 | 2 | 5 | 10 |
| Cable-01 | 3 | 4 | 12 |
| Sign-01 | 2 | 3 | 6 |
The critical asset register is a controlled subset of the master asset register. It should contain assets requiring enhanced management because of their risk or criticality.
This is more effective than maintaining a completely independent asset database.
Risk-based maintenance means maintenance resources are prioritized according to risk rather than simply equipment age or a fixed schedule.
This connects Division 03 directly with Division 09 — Maintenance Strategy & Optimization.
Risk mitigation defines what should be done to reduce unacceptable asset risk.
Criticality should not remain permanently fixed. An asset's criticality may change because of airport operational changes, runway/taxiway configuration changes, new equipment, system modification, redundancy changes, asset degradation, failure trends, obsolescence, or a change in regulatory requirements.
Criticality should be reconsidered following:
The 20 topics kept exactly as the risk-decision structure, each mapped to the primary question it answers.
| No. | Topic | Primary Question |
|---|---|---|
| 01 | Asset Criticality Methodology | How is importance determined? |
| 02 | Criticality Ranking | What priority level does this map to? |
| 03 | Safety-Critical Assets | Does failure threaten aviation safety? |
| 04 | Operationally Critical Assets | Does failure disrupt operations? |
| 05 | Runway Asset Criticality | How critical are runway assets specifically? |
| 06 | Taxiway Asset Criticality | How critical are taxiway assets specifically? |
| 07 | PAPI Criticality | How important is the PAPI system? |
| 08 | CCR Criticality | What circuits does this regulator supply? |
| 09 | Transformer Criticality | What function does this transformer support? |
| 10 | Cable Criticality | What does this cable's failure affect? |
| 11 | Sign Criticality | What operational function does this sign serve? |
| 12 | ALCMS Criticality | What does this system control and monitor? |
| 13 | Failure Consequence Assessment | What happens if this asset fails? |
| 14 | Probability of Failure | How likely is failure? |
| 15 | Risk Matrix | How do probability and consequence combine? |
| 16 | Asset Risk Ranking | Which assets carry the most risk? |
| 17 | Critical Asset Register | Which assets need enhanced management? |
| 18 | Risk-Based Maintenance Priority | How should maintenance resources be allocated? |
| 19 | Risk Mitigation Planning | How should unacceptable risk be reduced? |
| 20 | Criticality Review | When should criticality be reassessed? |
The mandatory outputs of Division 03.
Division 03 should remain the risk-decision layer. It determines which assets matter most, what can happen if they fail, how likely failure is, and where management and maintenance resources should be prioritized — it does not define the overall strategy (Division 01), and it does not hold the detailed asset data structure (Division 02).
Criticality = Consequence of Failure × Failure Likelihood. An old asset is not automatically a critical asset, and a new asset is not automatically low risk — criticality should always be based on consequence and likelihood evidence, not equipment age or purchase value alone.
This makes Division 03 the natural risk engine of the Asset Lifecycle Guide — the bridge between the asset data established in Division 02 and the later lifecycle decisions covering maintenance, asset health, reliability, lifecycle cost, refurbishment, replacement and digital asset management.
Quick answers about Asset Criticality & Risk Assessment in the AGL Asset Lifecycle Guide.
Division 03 is the risk-decision layer. It covers 20 topics on criticality methodology, safety/operational criticality, risk matrices, critical asset registers and risk-based maintenance priority.
It is a consistent method for determining the importance of each AGL asset. It considers safety, operational and regulatory consequence, failure consequence and probability of failure, and should not assign criticality simply because an asset is expensive.
Criticality ranking converts the assessment into an understandable priority level. That level then drives maintenance priority, inspection and testing frequency, spare strategy and condition monitoring. The actual rating thresholds should come from the approved airport risk methodology.
Division 03 covers runway assets, taxiway assets, PAPI, CCRs, isolating transformers, cables, airfield signs and ALCMS, each with its own criticality topic. It also identifies safety-critical and operationally critical assets as separate categories.
A CCR may be highly critical because one equipment failure can affect multiple field assets. The assessment therefore considers the number of circuits supplied, the runway or taxiway served, circuit importance, available redundancy and CCR capacity.
Failure consequence asks what happens if the asset fails, and probability of failure estimates how likely failure is within a defined period, using factors such as historical failures, age, condition, inspection findings and testing results. The risk matrix combines the two, and asset risk ranking then sets the relative priority of assets.
The critical asset register is a controlled subset of the master asset register. It holds the assets that need enhanced management because of their risk or criticality, with fields such as asset ID, type, location, criticality, risk score and safety consequence.
Risk-based maintenance prioritizes resources according to risk rather than simply equipment age or a fixed schedule, for example with more frequent inspection or testing, condition monitoring, critical spares and faster corrective response. Criticality is not permanent: a major or repeated failure, a major modification, system expansion or a change in runway or taxiway operation should trigger a review.
Effective AGL asset management starts with knowing which assets matter most when they fail.
Learn how criticality methodology, safety and operational ranking, failure consequence, probability of failure and risk-based prioritization connect across the complete AGL asset lifecycle.
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