The practical decision-learning and engineering-judgement division of the AGL Asset Lifecycle Guide. Divisions 01–23 establish the lifecycle framework, controls, data, risk, maintenance, cost, performance and governance. Division 24 shows how those principles are actually applied to real AGL assets — walking each case through Asset Condition → Performance → Reliability → Risk → Lifecycle Cost → Options → Decision → Implementation → Verification, and packaging the recurring judgement calls into 8 reusable decision models.
The question this division answers — Given everything we know about an asset's condition, performance, reliability, risk and lifecycle cost, what is the defensible engineering decision — continue, repair, refurbish, upgrade or replace — and how do we prove it was the right one?
Division 24 does not operate as a standalone case-study chapter. It sits at the point where the asset data, criticality, design, maintenance, cost, performance and governance work of the preceding divisions converges into an actual engineering decision.
Follows a runway-light asset from initial selection through eventual replacement — the flagship walkthrough case study for the division.
Demonstrates lifecycle management of taxiway lighting as a distributed asset population rather than a single unit.
CCR is particularly suitable for lifecycle analysis because it combines electrical performance, reliability, maintenance, controls and obsolescence in a single asset.
Examines the lifecycle of the AGL isolation transformer.
Determine whether the transformer should remain in service or be replaced based on condition, risk, reliability and lifecycle economics.
Considers cable as a system asset, not merely a consumable component.
Evaluates an airfield sign through its full lifecycle.
Determine whether the sign should be maintained, refurbished, modernized or replaced.
PAPI should be treated as a high-consequence operational asset — precision-approach path guidance leaves little margin for degraded performance.
Evaluate continued operation against refurbishment, modernization or replacement.
Considers the approach-lighting system as a complete system, not a collection of independent units.
Addresses both hardware and software lifecycle together, since a control system's two halves rarely age at the same rate.
An ALCMS may remain fully operational while becoming technologically obsolete.
Evaluates the lifecycle of a base-can installation — the buried interface most easily overlooked in above-ground condition surveys.
Determine whether to continue operation, repair, rehabilitate or replace.
Demonstrates when refurbishment is preferable to replacement.
The asset can achieve the required future performance at acceptable lifecycle cost and risk.
Demonstrates a complete replacement decision, end to end.
A documented replacement recommendation with:
Demonstrates that an asset can become a lifecycle risk before physical failure.
Demonstrates replacement triggered by a repeated-failure pattern rather than by age or scheduled review.
Demonstrates why the lowest purchase price is not necessarily the lowest lifecycle-cost option.
Select the option providing the most appropriate lifecycle value, not merely the lowest initial price.
One of the core decision models — used whenever a failed or degraded asset could plausibly go either way.
Refurbishment should not simply extend the calendar age of an asset. It should provide a justified improvement in:
Recognizes that age alone should not automatically trigger replacement.
Multiple factors demonstrate unacceptable future risk or lifecycle value.
Evaluates whether an asset can safely and economically provide additional useful life.
Particularly important for legacy AGL systems, where the asset itself may still function while the surrounding technology base moves on.
Determines whether a spare should be maintained in inventory.
Connects asset-management decisions with CAPEX planning.
All 23 topics at a glance, grouped by case study or decision model, with the core question each one answers.
| No. | Topic | Core Question |
|---|---|---|
| 01 | Runway-Light Lifecycle Case Study | Is continued maintenance, refurbishment, or replacement justified? |
| 02 | Taxiway-Light Lifecycle Case Study | What is the preferred strategy across a distributed light population? |
| 03 | CCR Lifecycle Case Study | Continue, repair, refurbish, modernize, or replace? |
| 04 | Transformer Lifecycle Case Study | Remain in service or replace, based on condition and risk? |
| 05 | Cable Lifecycle Case Study | Monitor, repair, partially rehabilitate, or fully replace? |
| 06 | Sign Lifecycle Case Study | Maintain, refurbish, modernize, or replace? |
| 07 | PAPI Lifecycle Case Study | Is a high-consequence optical asset still fit for continued operation? |
| 08 | Approach-Light Lifecycle Case Study | Does the system need rehabilitation, modernization, or replacement? |
| 09 | ALCMS Lifecycle Case Study | Is the system operational but technologically obsolete? |
| 10 | Base-Can Lifecycle Case Study | Continue, repair, rehabilitate, or replace the buried interface? |
| 11 | Asset Refurbishment Case Study | When is refurbishment preferable to replacement? |
| 12 | Asset Replacement Case Study | What does a complete, defensible replacement case look like? |
| 13 | Obsolescence Case Study | Can an asset become a risk before it physically fails? |
| 14 | Failure-Driven Replacement Case Study | When do repeated failures justify a replacement business case? |
| 15 | Lifecycle-Cost Optimization Case Study | Is the lowest price ever the lowest lifecycle cost? |
| 16 | Repair vs Replace | Repair now, or replace now? |
| 17 | Refurbish vs Replace | Does refurbishment deliver a justified improvement, not just extra age? |
| 18 | Upgrade vs Replace | Upgrade the existing system, or replace it entirely? |
| 19 | Continue Operation vs Replace | Does age alone justify replacement — or not? |
| 20 | Life Extension vs Replacement | Can the asset safely and economically provide more life? |
| 21 | Technology Migration Decision | Continue, partially migrate, fully migrate, or replace? |
| 22 | Critical Spare Decision | Should a spare be held, and where? |
| 23 | Capital Investment Decision | What investment option best serves need, cost, risk, and benefit? |
Every decision model in Division 24 ultimately resolves through the same ten-question ladder, in order.
Every Division 24 case study should use the same 13-part structure, so any two case studies can be compared directly.
The mandatory outputs of Division 24.
Division 24 should not operate as a standalone case-study chapter. It should demonstrate how Divisions 01–23 work together — turning a collection of processes into a decision-oriented asset-management system.
Core principle: AGL lifecycle management is not only about collecting asset data; it is about using asset data, condition, risk, reliability, cost and performance evidence to make defensible engineering decisions.
Quick answers about Lifecycle Case Studies & Decision Models in the AGL Asset Lifecycle Guide.
Division 24 is the practical decision-learning and engineering-judgement division. It covers 23 topics, made up of 15 lifecycle case studies and 8 decision models, spanning repair, refurbish, upgrade, replace and lifecycle-cost decisions for runway lights, taxiway lights, CCR, transformers, cables, signs, PAPI, approach lighting, ALCMS and base cans.
Division 24 is the practical decision-learning and engineering-judgement division of the guide. It contains 15 lifecycle case studies and 8 decision models (23 topics in total) that apply Divisions 01 to 23 to real asset decisions.
Case studies cover runway lights, taxiway lights, CCRs, isolation transformers, cables, signs, PAPI, approach lighting, ALCMS and base cans. They are followed by case studies on refurbishment, replacement, obsolescence, failure-driven replacement and lifecycle-cost optimization.
Repair versus replace, refurbish versus replace, upgrade versus replace, continue operating versus replace, life extension versus replacement, technology migration, critical-spare decision and capital investment decision.
Every case study uses the same 13-part structure so any two can be compared directly: case background, asset profile, current condition, performance, lifecycle history, risk assessment, lifecycle cost, options, option evaluation, decision, implementation, post-decision verification and lessons learned.
No. The continue-operating-versus-replace model recognizes that age alone should not automatically trigger replacement. Continuing can be justified where condition is acceptable, performance remains compliant, reliability is acceptable and critical spares are available.
The lifecycle-cost optimization case study demonstrates that the lowest purchase price is not necessarily the lowest lifecycle-cost option, since acquisition, installation, energy, maintenance, failure and spares costs all count.
The obsolescence case study shows that an asset can become a lifecycle risk before physical failure. The failure-driven replacement case study shows replacement triggered by a repeated-failure pattern rather than by age or a scheduled review.
Effective AGL asset management starts with learning from how real lifecycle decisions have actually played out.
Learn how repair-versus-replace, refurbish-versus-replace, upgrade-versus-replace and technology-migration decisions connect across the complete AGL asset lifecycle.
Turn technical reference knowledge into a deeper understanding of how AGL assets are planned, managed, operated and sustained throughout their lifecycle.
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