A standardized methodology for assessing the current condition, deterioration, remaining serviceability, maintenance requirement, and failure risk of AGL assets before functional failure occurs. This division is specifically focused on condition-based maintenance (CBM) and preventive-maintenance decision-making — moving beyond "is it working today?" to "is it deteriorating, and should we intervene before it fails?"
Core question — "What is the condition of the asset before it actually fails?" The objective is not simply to confirm whether an asset works today, but to determine whether its condition indicates Healthy → Deteriorating → Maintenance Required → High Risk → Replacement Required.
Key difference from other divisions — Division 02 asks "is the fixture physically/optically acceptable today?" Division 20 asks "was the test evidence properly performed and documented?" Division 21 asks "is the fixture deteriorating, and should we intervene before it fails?" Condition rating ≠ maintenance priority — the final decision always weighs Condition × Criticality × Failure Consequence × Redundancy × Availability.
Overall assessment of the physical, electrical, optical, mechanical, and operational condition of the asset, establishing the baseline condition-based maintenance (CBM) methodology applied across every other topic in this division.
Assessment of overall runway fixture condition, tracking deterioration trends that precede functional failure of runway edge, threshold, centreline, and touchdown-zone fixtures.
Overall condition assessment of taxiway edge, centreline, and guard-light fixtures, tracking deterioration and mechanical/frangible condition ahead of functional failure.
Overall physical and operational condition assessment of mandatory, location, direction, and information signs, tracking deterioration in enclosure, face, illumination, and structure.
Overall PAPI/APAPI condition assessment, tracking optical, housing, alignment, calibration, light-source, and environmental deterioration ahead of functional or guidance failure.
Assessment of CCR physical, electrical, control, cooling, and operational condition, tracking reliability trends ahead of functional or output failure.
Overall isolating-transformer condition assessment, tracking age, housing, lead, connector, and test-result trends ahead of insulation or connection failure.
Overall condition assessment of primary AGL cable, tracking insulation, fault-history, joint, and route trends ahead of cable failure.
Overall secondary-connector condition assessment, tracking contact, seal, corrosion, and heating/fault trends ahead of connection failure.
Overall base-can and civil condition assessment, tracking corrosion, drainage, settlement, and frangible-coupling trends ahead of failure or non-compliance.
Overall earthing and bonding condition assessment, tracking electrode, conductor, and resistance trends ahead of protective-earthing failure.
Overall condition assessment of the ALCMS/control system, tracking reliability, obsolescence, and supportability trends ahead of control-system failure.
Assessment of the physical and functional condition of stored AGL spares, ensuring critical replacement components remain usable and available when needed.
Verification of asset age, installation history, and service-life position against expected life, obsolescence, and supportability — the final review that determines whether an asset should move from maintain to planned replacement.
Common condition-rating scale, decision matrix, workflow, and records that apply across all 14 Division 21 topics — plus the cross-cutting trend-analysis, decision, and priority framework (Sections O–Q) that ties every topic together.
A single condition scale applied consistently across every topic in this division, used in conjunction with asset criticality rather than as a standalone decision.
| Rating | Condition | Meaning |
|---|---|---|
| C1 | Excellent | New/near-new condition; no meaningful deterioration |
| C2 | Good | Minor deterioration; normal preventive maintenance |
| C3 | Fair | Noticeable deterioration; monitor and plan maintenance |
| C4 | Poor | Significant deterioration; maintenance/replacement planning required |
| C5 | Critical | Severe condition; urgent intervention/replacement assessment |
| C6 | Failed/Unserviceable | Asset no longer provides required service |
Typical action associated with each condition rating. Condition rating alone does not set priority — see Section Q below.
| Condition | Typical Action |
|---|---|
| C1 — Excellent | Continue normal inspection |
| C2 — Good | Normal preventive maintenance |
| C3 — Fair | Monitor deterioration and plan intervention |
| C4 — Poor | Schedule maintenance/replacement |
| C5 — Critical | Urgent technical assessment/intervention |
| C6 — Failed | Remove from service/replace as applicable |
Parameters recorded against each asset, common across all 14 topics above.
| Parameter | Assessment |
|---|---|
| Asset ID | Verified / Not Verified |
| Asset Type | Verified / Not Verified |
| Location | Verified / Not Verified |
| Installation Date | Known / Unknown |
| Age | Recorded |
| Physical Condition | C1–C6 |
| Electrical Condition | C1–C6 / N/A |
| Optical Condition | C1–C6 / N/A |
| Mechanical Condition | C1–C6 / N/A |
| Environmental Condition | C1–C6 / N/A |
| Test-Result Trend | Stable / Deteriorating / Abnormal / N/A |
| Failure History | None / Occasional / Recurring |
| Repair History | Low / Moderate / High |
| Maintenance Frequency | Normal / Increasing / High |
| Obsolescence | No / Potential / Yes |
| Spare Availability | Available / Limited / Unavailable |
| Manufacturer Support | Available / Limited / Unavailable |
| Operational Criticality | Low / Medium / High / Critical |
| Failure Consequence | Low / Medium / High / Critical |
| Maintenance Requirement | None / Monitor / Plan / Urgent |
| Replacement Requirement | No / Planned / Urgent |
| Monitoring Frequency | Normal / Increased |
| Overall Condition | C1–C6 |
| Final Status | Normal / Defective / Unserviceable / Immediate Action Required |
Every observation should be assigned an appropriate final status:
NormalEquipment/condition satisfactory and operating as expected.
DefectiveAbnormality or defect identified but equipment remains operational or condition does not require immediate withdrawal.
UnserviceableEquipment or system is not available for its intended function.
Immediate Action RequiredCondition presents an operational, electrical, safety, or airside risk requiring immediate escalation/action.
Each Division 21 condition record should include:
Condition rating ≠ maintenance priority. A C3 runway centreline light may require higher priority than a C4 non-critical spare component, because asset criticality and operational consequence differ. The final decision therefore always weighs:
Illustrates how a condition inspection differs from a pass/fail current inspection, and why deterioration is intervened on before functional failure.
Division 21 should not duplicate the individual inspection divisions — it asks a fundamentally different question about the same asset.
"Is the runway fixture physically/optically acceptable today?"
"Was the photometry/test evidence properly performed and documented?"
"Is the runway fixture deteriorating, and should we intervene before it fails?"
Preventive-maintenance condition inspection is intended to
It does not replace
Central philosophy
Quick answers about preventive maintenance condition inspection in the AGL Inspection Handbook.
Division 21 contains 14 published topics in 17 sections (A–Q). It gives a standardized methodology for assessing the current condition, deterioration, remaining serviceability, maintenance requirement and failure risk of AGL assets before functional failure occurs, focused on condition-based maintenance and preventive-maintenance decision-making.
It asks a different question about the same asset. Division 02 asks whether the runway fixture is acceptable today, Division 20 asks whether the test evidence was properly performed and documented, and Division 21 asks whether the fixture is deteriorating and whether to intervene before it fails.
A single scale applies across the division: C1 Excellent, C2 Good, C3 Fair, C4 Poor, C5 Critical and C6 Failed/Unserviceable. It is used together with asset criticality, not as a standalone decision, and each rating has a typical action from continuing normal inspection through to removal from service or replacement.
No. Condition rating does not equal maintenance priority. The decision weighs condition, criticality, failure consequence, redundancy and availability, so a C3 runway centreline light may need higher priority than a C4 non-critical spare component.
Yes. In the division's worked example, a runway edge light is operational and passes a current inspection, but lens degradation, corrosion, repeated moisture ingress and increasing maintenance interventions lead to a C4 Poor rating, with increased monitoring and planned replacement before functional failure.
It identifies the asset, reviews history, inspects current condition, reviews previous defects, test results and failure history, assesses deterioration, assigns a condition rating, assesses criticality and failure consequence, determines maintenance, monitoring and replacement requirements, assigns priority, and records follow-up.
Yes. This handbook is an uncontrolled educational reference, not an approved procedure. The airport's approved inspection schedule, SMS procedures, ATC instructions, NOTAM procedures and local aerodrome regulations always take precedence, and the current revision of any official document should be verified before use.
Yes. Each inspection topic has a Download as Word option that produces an uncontrolled Word checklist template (description, a tick-box inspection table and an inspector sign-off block) for personal reference and internal training, to be reviewed and adopted under the user’s own document control.
Preventive maintenance condition inspection is where scheduled-interval and wear-trend condition awareness begins. Go beyond identifying defects and build the technical knowledge to understand why abnormalities occur, how they affect system serviceability, and when further testing, troubleshooting, maintenance or corrective action is required.
Develop structured knowledge across:
Learn to connect the inspection process with the wider AGL engineering lifecycle.
Inspect with purpose. Understand the system. Act with technical confidence.
Please read before relying on any content on this page or on any record downloaded from it.