Airworthiness Directives: methodology and limitations
What the numbers on each model's Compliance section mean, where they come from, and what they can't tell you. Snapshot as of October 8, 2026.
Sources
AD records come from two independent FAA sources: the Federal Register API (the authoritative publication record for every issued AD) and the govinfo MODS XML metadata service (the U.S. Government Publishing Office's structured catalog of the same documents). Both are public APIs and we pull them slowly. Pulling from two independent sources rather than one is what lets us cross-check (see Corroboration below).
Applicability extraction (matching ADs to models)
AD applicability is extracted from each directive's published text. For most modern ADs that's the title; for older directives and many engine ADs it's the Applicability paragraph in the body. The extraction handles several common syntactic forms, with manual overrides for the cases the automatic parse comes out wrong on.
Where applicability can't be resolved cleanly, the AD goes into an unresolved bucket and doesn't display on any model page. A guess that maps an AD to the wrong model would be worse than nothing.
Supersession derivation
ADs get continuously revised. A new AD almost always supersedes one or more predecessors and replaces the older directive's requirements. We derive the supersession graph from each AD's body text so the per-model summary can distinguish active directives from those that have been replaced.
An AD counts as active if no later AD supersedes it, otherwise it's superseded. The per-model summary counts both, and recent supersessions appear in the recent-directives list with a Superseded badge so you can see the original directive even after it's been replaced.
JASC / ATA bucketing
Each AD is tagged with one or more JASC (Joint Aircraft System/Component) codes, which follow the ATA Chapter convention. The corpus contains a mix of legacy 2-digit chapter codes and modern 4-digit JASC codes, and the by-JASC chart on each model page shows both forms as separate bars.
That means a model with both legacy-form and modern-form ADs in the same JASC chapter can show two bars rather than one merged total. We don't merge them, because the published codes are the FAA's own labelling and aggregating across resolutions would lose a distinction the FAA chose to draw.
Corroboration against an independent source
Every directive we ingest is cross-checked against its govinfo MODS XML record on multiple identity fields. The Federal Register API and the govinfo MODS service are run by two different U.S. government organisations (NARA's Office of the Federal Register, and the Government Publishing Office), so a per-field match is a real cross-source agreement rather than one source agreeing with itself.
In our most recent corroboration run, 97.7% of records matched on all checked fields. The most common driver of a mismatch is an AD that was later issued a revision: the Federal Register row carries the original document while our cross-check source reflects the revision. That's a known difference, not a data problem.
Freshness and dates
Read-model as of: October 8, 2026. That's when we last rebuilt the published summaries from the underlying corpus. Last ingest activity: October 8, 2026. That's the most recent record we pulled in from the Federal Register feed.
The two dates can diverge when rebuilds and ingests run on different cadences. Both are shown so you can see any gap. ADs are issued continuously, so always verify against the current FAA AD listing before any maintenance action.
Manufacturer variants and canonical pages
The FAA registers some models under multiple manufacturer names (Cessna, Textron Aviation Inc., Cessna Aircraft Co., and so on for the same model). We compute applicability against the AD's canonical manufacturer, which may differ from the manufacturer slug a particular page is served under. A variant page whose URL doesn't match the canonical slug won't show a Compliance section even when ADs apply to the underlying type-certificated airframe. Visit the canonical-manufacturer page for the same model to see its ADs. (Consolidating this in one place is on the V2 roadmap.)
Scope and limits
This isn't legal advice or a regulatory determination. The Compliance section pulls together the FAA's own published facts about a model into a per-model summary. It doesn't interpret them, prioritise them, or substitute for the AD itself. Pilots, owners, mechanics, and operators need to verify any AD affecting their airframe against the FAA's authoritative listings before any maintenance, flight, or certification action.
The summary doesn't predict future ADs, score the airframe's compliance burden, or say anything about how any particular tail number has been maintained. The only directive prose we surface verbatim is the AD's own title. We don't republish AD body text or write summaries of it.
Last updated
Read-model snapshot: October 8, 2026. The pipeline re-fetches the Federal Register feed on a scheduled cadence and rebuilds the published summaries from it. Numbers on this page reflect the most recent run.