The CORSIA Compliance Calendar: An Airline's Yearly Rhythm

How CORSIA work falls across a single year and across a three-year compliance period, with an owner for each step and a planning template you can adapt for your own team.

CORSIA work is not a single deadline. It is a loop that repeats every year, wrapped inside a longer loop that closes every three years. Airlines that do well with it treat both loops as standing items in their planning calendar, the way they treat audits or insurance renewals.

This page sets out the sequence. We have deliberately left out exact submission dates: they are set in ICAO's rules and by your national authority, and can be adjusted. Take the current dates from the DGCA (for Indian operators) or ICAO, and drop them into the template below.

The two loops

The annual loop is about data: record fuel and emissions for the year, check them, report them.

The period loop is about units: work out how much you owe for the compliance period, buy eligible units, cancel them, and report the cancellation.

The periods follow the scheme's phases. The first phase runs 2024–2026; the second phase, 2027–2035, is split into three-year periods in the same way. The pilot ran 2021–2023.

The annual loop, step by step

Before the year begins: the monitoring plan

Your emissions monitoring plan describes how you will measure fuel on each international flight, which method you use, and how you handle gaps. It needs to be in place and accepted by your authority before you rely on it. Any change to fleet or method usually means updating it.

Owner: flight operations or fuel efficiency team, with compliance.

During the year: collect the data

Fuel uplift and burn are recorded flight by flight. Most airlines pull this from their fuel management or flight data systems. Keep an eye on new routes and aircraft types, because they affect both your threshold position and your offsetting share.

Owner: operations data team.

A useful habit: reconcile monthly rather than once at year end. Errors found in month two cost an afternoon. Errors found in month thirteen cost a verification finding.

After the year closes: the emissions report

Compile the year's total, split by route (State pair), and convert fuel to CO₂ using the fixed factors (3.16 tonnes per tonne of Jet-A or Jet-A1, 3.10 for AvGas or Jet-B).

Owner: compliance lead.

Next: independent verification

An accredited verifier checks your report against your monitoring plan and source records. Book the verifier well before year end; good verifiers fill their diaries early.

Owner: compliance lead, with support from operations data.

Then: submission to the authority

The verified report goes to your national authority, which passes aggregated data to ICAO. ICAO uses the sector's data to set the growth factor that feeds each operator's offsetting calculation.

Owner: compliance lead; accountable manager signs off.

The period loop, step by step

Through the period: estimate and buy in stages

You do not need to wait until the end of the period to start buying. Many operators estimate their requirement each year using their reported emissions and the published growth factor, then buy part of the expected volume as they go. Our calculator gives a working estimate once you enter the official growth factor.

Buying in stages spreads price exposure and leaves time to check documents properly. Use our eligible units checklist on every purchase.

Owner: finance and procurement, with compliance.

After the period ends: confirm the final figure

Your authority confirms your total offsetting requirement for the period, based on your verified emissions, the growth factors and any claimed reductions from eligible fuels.

Then: cancel and report

You cancel the matching volume of eligible units in a registry, and report the cancellation to your authority, which checks it against your requirement. Units must be eligible for that specific period.

Owner: compliance, operating the registry account.

A planning template

Use this as a starting point and add your authority's dates in the right-hand column.

Stage	Loop	What happens	Owner
Monitoring plan in place	Annual	Plan accepted; updates filed after fleet or method changes	Operations, compliance
Data collection	Annual	Flight-by-flight fuel recorded; monthly reconciliation	Operations data
Emissions report drafted	Annual	Totals by State pair, fuel converted to CO₂	Compliance
Verification	Annual	Verifier reviews report and records	Compliance
Report submitted	Annual	Verified report sent to authority	Compliance, accountable manager
Interim estimate and purchase	Period	Requirement estimated; part volume bought	Finance, procurement
Final requirement confirmed	Period	Authority confirms period total	Compliance
Cancellation and report	Period	Units cancelled; cancellation reported	Compliance

Things that slip

Registry access. Opening an account can take longer than expected. Start well before you need to cancel.
The verifier booking. Leaving it to the last month risks a late report.
Period mismatch. Units bought for one period cannot be assumed to work for the next. Check vintage and approval each time.

For the bigger picture behind these steps, see CORSIA explained for management, and if you are unsure whether you are in scope, start with the coverage self-check.

If you would like us to build this calendar out with your team's real dates and owners, the services page sets out where we can take work off your desk.