Component accounting is the discipline of treating significant parts of one item of property, plant and equipment (PPE) separately when those parts have different useful lives or consumption patterns. It matters because a single asset invoice can hide economically different components: an aircraft body and its major inspection, a building and a lift system, or a production line with a furnace lining that needs replacement much earlier than the main machine.
Under Ind AS 16, the objective is not to split every nut and bolt. The focus is on parts whose cost is significant in relation to the total cost of the item. ICAI's current Compendium of Indian Accounting Standards includes Ind AS 16, Property, Plant and Equipment, and its 2025-2026 Volume II index provides the current Ind AS collection in which the standard sits.
What does the component approach require?
ICAI's official Ind AS 16 learning material summarises the component approach clearly: each major part of an item of PPE whose cost is significant in relation to the total cost should be depreciated separately. If different significant parts have the same useful life and depreciation method, they may be grouped for determining the depreciation charge.
This means the accounting unit used for depreciation can be narrower than the physical asset visible on the factory floor. A machine may be one operational asset but several depreciable components in the fixed asset register.
Step 1: Identify components using economic substance, not a fixed percentage
Start with the engineering and commercial reality of the asset. Review purchase specifications, bills of quantities, major maintenance cycles, warranties, technical reports and expected replacement intervals. Ask which parts are significant in cost and whether they will be consumed or replaced on materially different timelines.
Ind AS 16 does not prescribe one universal percentage that automatically makes a component significant. The entity therefore needs a reasonable, consistently applied judgement supported by facts rather than treating an internal threshold as a substitute for the accounting assessment.
- Identify parts with significant cost relative to the whole item.
- Compare expected useful lives and consumption patterns.
- Consider major inspection or overhaul cycles that are conditions of continuing operation.
- Document why a part is separated, grouped with another component or left within the main asset.
Step 2: Allocate the asset's cost to the components
Once components are identified, allocate the recognised cost among them on a reasonable basis. Supplier pricing may provide the split; otherwise engineering estimates, replacement-cost information or other support may be needed. The objective is a defensible allocation, not artificial precision.
The asset register should retain enough component detail to calculate depreciation and later derecognise a replaced part. A single gross-block number for the whole machine often makes that difficult.
Step 3: Set useful life, residual value and depreciation method for each component
Each significant component is depreciated over its own useful life using a method that reflects how its economic benefits are expected to be consumed. Components that share the same useful life and depreciation method may be grouped for the depreciation calculation.
Ind AS 16 requires residual value and useful life, and the depreciation method, to be reviewed at least at each financial year-end. Revised expectations are accounted for prospectively as changes in accounting estimates under Ind AS 8. The estimates should therefore be connected to current technical and operating evidence.
Worked example: one machine, three components
Assume a company acquires a production machine for ₹120 lakh. Technical analysis supports the following cost allocation: ₹80 lakh for the main structure with a 12-year useful life, ₹25 lakh for a furnace lining with a 4-year useful life, and ₹15 lakh for a control system with a 6-year useful life. Assume zero residual value and straight-line depreciation purely for illustration.
- Main structure: ₹80 lakh divided by 12 years, approximately ₹6.67 lakh a year.
- Furnace lining: ₹25 lakh divided by 4 years, ₹6.25 lakh a year.
- Control system: ₹15 lakh divided by 6 years, ₹2.50 lakh a year.
The first-year depreciation is therefore approximately ₹15.42 lakh. Depreciating the entire ₹120 lakh over 12 years would produce only ₹10 lakh a year and would fail to reflect the much faster consumption of the lining and control system.
Step 4: Account correctly when a component is replaced
Component accounting becomes especially important at replacement. ICAI's Ind AS 16 material explains that when the cost of replacing a part satisfies the PPE recognition criteria, the new cost is recognised in the carrying amount and the carrying amount of the replaced part is derecognised.
Suppose the furnace lining in the example is replaced after three years for ₹30 lakh. The old lining originally cost ₹25 lakh and, under the simplified assumptions above, has ₹6.25 lakh of carrying amount remaining after three years. If the replacement qualifies for recognition, the entity capitalises the new lining and derecognises the remaining carrying amount of the old lining rather than leaving both costs in the fixed asset register.
Routine day-to-day servicing is different: ordinary labour and consumables are generally expensed as incurred. A qualifying replacement creates a new recognised component while the old component is removed.
Step 5: Treat major inspections as replacement components when the criteria are met
Some assets can continue operating only after periodic major inspections or overhauls. ICAI's Ind AS 16 material explains that the cost of each major inspection is recognised in the carrying amount as a replacement when the recognition criteria are satisfied. Any remaining carrying amount relating to the previous inspection is derecognised, even if that previous inspection was not separately identified and depreciated when the asset was acquired.
That makes inspection accounting more than a maintenance accrual exercise. For aircraft, heavy plant and similar assets, finance teams should identify inspection components from the start so the replacement cycle is visible in the asset register.
Fixed asset register checklist
- Maintain a parent asset ID plus separate component IDs where componentisation is required.
- Record the allocated original cost of each significant component.
- Store the useful life, residual value and depreciation method for each component.
- Link technical evidence supporting different useful lives or replacement cycles.
- Track replacement dates and derecognition of the component removed.
- Identify major inspection components and their expected intervals.
- Review useful lives, residual values and methods at year-end and document changes.
- Reconcile component-level records to the general ledger and PPE disclosures.
Common mistakes to avoid
- Depreciating a complex asset entirely over the useful life of its main structure.
- Using an arbitrary percentage as the only test of significance.
- Capitalising a replacement without derecognising the old component.
- Expensing every overhaul automatically even when a major inspection meets the recognition criteria.
- Keeping insufficient component detail in the fixed asset register to identify the carrying amount of replaced parts.
- Failing to revisit useful lives and depreciation methods when operating conditions change.
Practical takeaway
Good component accounting starts before depreciation is calculated. Identify economically significant parts, allocate cost on a supportable basis, set component-specific lives and methods, and keep the asset register detailed enough to handle replacements and major inspections. The result is not merely a more elaborate fixed-asset schedule; it is depreciation and derecognition that better reflect how the PPE is actually consumed.
