EASA vs FAA Airworthiness Directives: Comply-Once, Cross-References, and What Actually Applies
If your fleet lives entirely under one authority, an Airworthiness Directive is a single object with a single number. The moment you operate across EASA and FAA — or manage aircraft whose State of Design differs from their State of Registry — that stops being true. The same unsafe condition can arrive as two directives, from two authorities, under two numbers, on two different dates. Managed well, that's a non-event. Managed by hand, it's where fleets double-count work or miss a directive entirely.
This article explains how EASA and FAA directives relate, what "comply-once" really means, and how to keep a mixed-fleet AD list correct.
Two authorities, overlapping directives
EASA and FAA both issue Airworthiness Directives to correct unsafe conditions, and their scopes overlap heavily because the world's aircraft are largely designed under one of the two. A structural issue on an Airbus type and a systems issue on a Boeing type will each generate a directive — but which authority issues first, and which one you're legally bound by, depends on where the aircraft was designed and where it's registered.
State of Design vs State of Registry
Two roles matter:
- State of Design is the authority responsible for the type certificate — EASA for an Airbus, the FAA for a Boeing, and so on. The State of Design normally issues the original AD for a design defect.
- State of Registry is the authority of the country where the aircraft is registered, and it's the authority whose mandate you're operating under.
When those two are the same authority, life is simple. When they differ — a US-designed aircraft on a European register, or vice versa — the State of Registry generally adopts the State of Design's directive so that it becomes mandatory for you too.
MCAI and foreign ADs: the comply-once principle
That adoption mechanism is why you see the same defect show up twice. The receiving authority republishes the originating authority's directive as Mandatory Continuing Airworthiness Information (MCAI) — often called a foreign AD. EASA, for example, issues ADs that adopt FAA directives for FAA-designed types, and the FAA does the reverse.
The key principle is comply-once: because the two directives address the same unsafe condition with the same corrective action, complying with one is normally accepted as complying with the other. You don't perform the work twice. But — and this is the whole point — you only get the benefit of comply-once if your records link the two directives as equivalents. If they float as two unrelated line items, you lose the simplification and inherit the risk.
Cross-references: the same directive under two numbers
In practice, the originating AD and the adopting AD carry different identifiers, different formats, and sometimes different revision histories. A robust AD record therefore maintains a cross-reference: this EASA number corresponds to that FAA number, they address the same condition, and compliance with either satisfies both for the affected aircraft.
Keeping those cross-references current is ongoing work. Revisions and supersedures don't always happen in lockstep across authorities, so the mapping has to be maintained, not set once.
The two failure modes on a mixed fleet
Without reliable cross-referencing, two things go wrong:
- Double-counting. The same corrective action appears as two open items. Your workload looks larger than it is, your compliance status looks worse than it is, and an engineer can waste time investigating a "gap" that's really the same directive seen twice.
- The missed cross-jurisdiction AD. This is the dangerous one. An aircraft on one register is subject to a directive issued by the other authority — but because you were only watching one source, or because the foreign-AD adoption wasn't picked up, it never enters your list at all. On a registered aircraft, that's an audit finding waiting to happen, and worse, a real safety gap.
Both failure modes come from the same root: treating each authority's feed as an independent stream instead of reconciling them into one deduplicated, cross-linked picture.
How deduplication and comply-once linking keep the list honest
The fix is to stop managing "EASA ADs" and "FAA ADs" as separate lists and start managing the set of distinct unsafe conditions that apply to each aircraft, with the authority references attached. That means:
- ingesting directives from both authorities,
- recognizing when an EASA and an FAA directive are the same underlying condition,
- linking them as a comply-once pair,
- and presenting one applicable item per condition, per aircraft — with both authority references and a single compliance status.
Done right, an engineer sees a clean, per-aircraft list with no duplicates and no gaps, and can prove — for either authority's audit — that the condition was addressed and by which action.
How Aviagent handles it
Aviagent ingests EASA, FAA, TCCA, and ANAC directives daily and deduplicates comply-once directives across regulators as part of determining what applies to each aircraft. Cross-references are maintained so that a single corrective action satisfies both authorities where they've mandated the same condition — and so that a directive adopted by one authority for an aircraft on the other's register still surfaces on your list. As always, the applicability and the cross-reference are shown with their reasoning, and your engineers confirm them; the software does the reconciliation, the judgement stays with your team.
The result is the honest version of your fleet's AD picture: every distinct condition once, no double-counting, and nothing missed because it arrived under the "other" authority's number.
FAQ
If I comply with an EASA AD, do I still have to action the FAA one? Usually not — where the two directives address the same unsafe condition, the comply-once principle means complying with one satisfies the other. But you must have the two linked as equivalents; otherwise they'll be tracked (and worked) as separate items.
What is a foreign AD or MCAI? Mandatory Continuing Airworthiness Information — a directive one authority issues to adopt another authority's original AD, so that it becomes mandatory for aircraft on its register. It's how the same defect becomes enforceable across jurisdictions.
Which authority's AD am I legally bound by? Primarily your State of Registry. When your State of Registry differs from the State of Design, the State of Registry typically adopts the design authority's directive, so you end up bound by the adopted version.
How do I avoid missing a cross-jurisdiction AD? Reconcile both authorities' feeds into one deduplicated, cross-linked list rather than watching a single source. That's exactly the gap a manual, single-authority process tends to leave open.
See which ADs apply to your fleet — free, in about 30 seconds. Try the free AD lookup, or book a 20-minute walkthrough.
Related reading: Which airworthiness directives apply to your aircraft (the pillar) · Superseded and recurring ADs · Building an audit-ready AD evidence chain.
About the author — Satya Neerupudi is Founder & CEO/CTO of Aviagent and an aeronautical engineer with 25 years in continuing airworthiness at SAS, GE Aviation, Pratt & Whitney, and HAL.