The ARC and the airworthiness review: an operator's calendar

The airworthiness review is the one moment in the year when somebody from outside looks at the complete set of an aircraft’s records at once. Not one inspection, not one directive — all of it. Which makes it the one moment when small documentation gaps stop being small.

This is not a guide to conducting a review (that is the job of qualified review staff). It is a calendar and a checklist for the operator: what to prepare, when, and what most commonly stops the date from closing.

A review is not maintenance

The distinction everything starts from:

• Maintenance answers “were the required actions carried out on the aircraft”. It ends with a certificate of release to service and concerns specific tasks.
• The airworthiness review answers “do the records show the aircraft is airworthy”. It ends with an Airworthiness Review Certificate (ARC) and concerns the whole record system.

An aircraft can have every item of maintenance done and still fail an airworthiness review — because it cannot be demonstrated. The reverse never happens. That is worth understanding before preparation starts: to a large extent the subject of the review is the quality of your documentation.

The process is described in ML.A.903 and has two parts: a review of the records and a physical survey of the aircraft, which checks that the physical state matches what the records claim (markings, placards, equipment, obvious damage, configuration).

One year, extensions, then a full review again

The certificate is issued for one year. ML.A.901 allows it to be extended by the organisation managing the aircraft’s continuing airworthiness — typically twice, by one year each time — provided the aircraft has remained in a controlled environment: continuously managed by an approved organisation, with all maintenance carried out and released by an approved body.

Two things worth verifying in the consolidated text for your configuration, because they differ depending on who manages continuing airworthiness and what kind of aircraft it is:

1. who may conduct the review and issue the certificate — Part-ML opens this to more bodies than the old Part-M did, including a route for lighter aircraft outside commercial air transport,
2. the effect of a break in the controlled environment — for example a period without a management contract, or maintenance released outside an approved body. Such a break usually closes the door to an extension.

That second point tends to be an unpleasant discovery when buying a used aircraft: a history with a gap in continuing airworthiness management means a full review, not an extension. It is also the single most useful thing to check before signing, and it takes one email.

What the records review covers

The list is predictable, which means you can run it as your own checklist:

Area	What has to line up
Utilisation	continuous, no gaps, no two versions of the same number
Maintenance programme	current revision, applied to this individual aircraft
Programme tasks	compliances with date, counter state and a CRS reference
Airworthiness directives	complete status: applicable / not applicable, with justification
Manufacturer bulletins	applicability assessed, decision taken, decision recorded
Life-limited parts	remaining life and installation history for every item
Defects	open, deferred (with basis and deadline), closed
Mass and balance	current, after every modification that affects it
Modifications and repairs	approved data, evidence of embodiment
Aircraft documents	valid and complete

Every row of that table is a question that will be asked anyway. The only variable is whether the answer takes two minutes out of a system or two days out of the filing cabinets.

The operator’s year

The review is an annual event, but preparing for it is a continuous process. A rhythm that works:

• Daily — a complete techlog entry and defect closure. Everything else is built from those records; one missing entry stays visible in the utilisation figure for a year.
• Monthly — a pass over the due list and over anything marked “no data”. A task that cannot be computed is a documentation problem, not an engineering one, and it is cheapest to fix immediately.
• Quarterly — a review of new directives and bulletins together with the record of each decision. Covered in detail in the write-up on ADs, SBs and SLs.
• 90 days before the ARC expires — schedule the maintenance that has to precede the review, and book the review staff.
• 60 days before — the first completeness check (list below).
• 30 days before — the second check and closure of the gaps. If anything has to be shipped in, this is the last moment.

That calendar holds more than one deadline, and not all of them concern airworthiness: insurance, the radio licence, the noise certificate, and — in a training organisation — instructor qualifications. Formally these are separate matters. Practically each of them grounds the aircraft just as effectively. They belong in the same calendar with the same lead time; 60 and 30 days works well.

The 60-day checklist

Eight items that explain most of what reviews find:

1. Utilisation reconciles. The sum of increments from entries matches the current state of every counter. A mismatch means a missing flight or an unrecorded correction.
2. No task in a “no data” state. Every task has a computable due point or an explicit reason why it has none.
3. Directive status is complete for every type in the fleet, with the assessment recorded for the “not applicable” ones too.
4. Bulletins assessed, and those marked applicable have matching tasks with due points.
5. Life-limited components have a legible installation history: on which aircraft and for how many hours they ran.
6. Deferred defects have a basis and a deadline, and no deadline has passed.
7. Aircraft documents are valid and filed in their current issue, with previous issues retained as history rather than deleted.
8. Mass and balance matches the current configuration.

Item seven deserves emphasis: a new ARC is filed as a new document, and the previous one stays. Continuity of certificates is part of the aircraft’s history and is usually the first thing a buyer asks to see.

What actually derails reviews

Not failures. Three documentation problems:

• A gap in utilisation. A handful of flights with no entry — usually from a period when “the paper stayed in the aircraft”. Reconstructing them afterwards is possible, but it requires a deliberate, documented reconstruction, not the addition of plausible numbers.
• Drifting due points. Inspections carried out within tolerance and then counted from the date of accomplishment let the aircraft fly longer between visits than the programme intends. The mechanism and the correct arithmetic are in the write-up on tolerances without drift.
• No trace of a decision about a document. “Not applicable” without a record looks like “not checked”. To the person conducting the review those are the same thing.

All three share a property: they build quietly over many months and surface on a single day. Which is why preparation for an airworthiness review does not begin sixty days before the date — it begins with the first entry after the previous review, or, if you are currently leaving paper behind, with the opening balance.