How AD tracking works in TachMinder

Airworthiness Directives are the highest-stakes items in your maintenance records, and they're the ones TachMinder works hardest on. This guide explains what ADs are, how the app finds the ones that may apply to your aircraft, and what a proper AD compliance record has to contain.

What an AD actually is

An Airworthiness Directive is a legally enforceable rule issued by the FAA under 14 CFR Part 39 to correct an unsafe condition found in a product. ADs are not suggestions and not service bulletins — they carry the force of regulation.

Four product categories — including the one everybody misses

ADs target four categories of product: the aircraft/airframe itself, the engine, the propeller, and appliances. The first three are familiar territory. The fourth — appliances — covers installed equipment: autopilots, ELTs, transponders, ADS-B units, vacuum pumps, magnetos, starters, alternators, fuel pumps, and similar gear.

Appliance ADs are the ones traditional type clubs don't track, and for a structural reason: what applies depends on what's actually installed in your particular airplane, which no type-wide list can know. That's why keeping the Equipment tab's installed-equipment inventory current matters so much — TachMinder's AD matching for appliances runs against that inventory. An autopilot the app doesn't know about is an autopilot whose ADs it can't surface. See Equipment inventory for how to keep it current.

Where the AD data comes from

TachMinder maintains a platform-wide AD catalog. Its primary source is the Federal Register — the canonical publication of every Part 39 AD — and the catalog is refreshed on an ongoing schedule. The app then matches catalog ADs against each aircraft's airframe, engine, propeller, and installed equipment to surface candidates that may apply.

You stay in control of what gets tracked

Matching produces candidates, not conclusions. The AD Research tab is where you review them: for each matched AD, you decide whether to mark it Tracked or Not Applicable. ADs found while parsing uploaded documents — say, a logbook page that mentions an AD signoff — are staged for your review the same way; only ADs you've confirmed, and that resolve to an entry in the catalog, are committed to your aircraft's record. Nothing lands in your AD list because a parser thought it saw something. (See Uploading documents for how parsed records flow through review.)

What a compliance record has to contain

Every AD compliance record in TachMinder keeps what 14 CFR §91.417(a)(2) requires: a description of the work performed, the date of completion, and the time in service when it was done. For recurring ADs, the record also carries the next-due time or date, per §91.417(a)(2)(v) — that's what lets the app run a live countdown on a recurring AD instead of just noting that it was complied with once.

When the record is a return-to-service signoff, it additionally carries the mechanic's signature, certificate number, and kind of certificate, per §43.9(a)(4). TachMinder stores what the mechanic signed — it does not, and cannot, certify the work itself.

Matching finds candidates; the FAA is the authority

It bears repeating outside the blue box: TachMinder's matching helps you find ADs worth looking at. The FAA's database at drs.faa.gov is the authoritative source, and applicability must be verified there and with your mechanic. A match in the app means "review this," never "this definitely applies."

Once ADs are being tracked, the app classifies the state of each one's records — see The five AD compliance states for what those states mean and why they're deliberately honest.