Key takeaway
Keep the completed action and the continuing obligation as separate records. A future action marker is meaningful only with its actual directive, revision, method and time basis.
Start with the obligation that survives the task
An aircraft archive contains a signed maintenance entry and a closed work order. A later reviewer asks when the recurring airworthiness-directive action is next required. The completion flag cannot answer that question by itself. The owner needs the applicable directive and the continuing status record, connected to the evidence of the action actually performed.
For aircraft within its scope, 14 CFR 91.417 distinguishes records of maintenance performed from current applicable AD status. The latter includes the method of compliance, AD number and revision date, and, for recurring action, the time and date when the next action is required. These are different evidentiary jobs. One describes an event; the other preserves an obligation after that event.
This article concerns retrospective record interpretation under that US rule. Section 91.401 sets the applicability and specified continuous-airworthiness-program exclusions. An authorized aviation reviewer must establish the applicable regime before adopting these fields. No real aircraft, AD applicability search or airworthiness determination is supplied here.
Follow a fictional obligation through one completed action
The hypothetical timeline below invents AD-EXAMPLE-7, a recurring rule of 250 applicable operating hours and a counter called C. These names and the interval are illustrative; they are not a real directive or maintenance recommendation. Assume solely for this arithmetic that the invented rule measures from the documented action at C = 1,000.
The derived marker is 1,000 + 250 = 1,250 on counter C. It remains conditional on that premise. A row saying only “1,000 hours” cannot inherit the result: it might refer to another component, another counter or a different interpretation of the directive. Preserve that uncertainty rather than calculating a precise-looking marker from an unidentified clock.
| Retained item | What the fictional evidence establishes | What remains separate |
|---|---|---|
| Action entry: C = 1,000 | The stated action was documented at this counter value | Whether the action satisfies the applicable directive |
| Rule premise: repeat after 250 applicable hours | Conditional next marker: C = 1,250 | Actual directive, revision and compliance method must support the premise |
| Work order marked complete | The administrative task was closed | The recurring obligation continues under the invented rule |
| Another entry: 1,000 hours, counter unspecified | A number was recorded | No transferable next-action calculation |
| Note: terminating action claimed | A claim exists | Actual directive/revision and supporting authority are not supplied |
Attach applicability to the configuration being reviewed
FAA guidance explains that applicability can depend on the product model, installed parts or modifications. A search limited to an aircraft name can therefore leave questions about the engine, propeller or installed appliances unanswered. The applicable AD supplies its own compliance time; the fictional 250-hour premise must never become a default interval for other records.
Give a later reviewer the identity and configuration evidence used in the original applicability assessment, together with the directive identifier and revision actually considered. If a modification changed that assessment, retain the dated reasoning and its supporting documents. An export that keeps the latest status while dropping the configuration history may conceal why an earlier action was applicable.
A claimed terminating action deserves its own evidence link. Do not convert its wording into a permanent “closed” status because a work order uses that label. Establishing whether it ends a particular recurring requirement belongs to the qualified review of the actual directive and action.
Carry the event and the current status through transfer
Section 91.417 also distinguishes retention categories; the current-status records specified in paragraph (a)(2) have a retained-and-transferred role that differs from the work records in paragraph (a)(1). A flat folder of completion PDFs can preserve individual events while losing the structured status needed to interpret them. Conversely, a current-status spreadsheet can lose the underlying action evidence.
For the fictional record, preserve two connected objects: the action entry at C = 1,000 and the status assertion derived from the stated rule. Store the calculation basis with the latter. When a correction changes that basis, retain what changed and why, so a reviewer can distinguish a corrected interpretation from an additional maintenance event.
Recordkeeping duties do not establish permission to disclose or license the archive. Any proposed external use needs its own authority review, including material created by maintenance providers or containing other parties’ information.
Describe what the history can actually reconstruct
The completed illustrative archive can answer three bounded questions: which fictional action was documented, which stated counter supports the next marker, and which claim still lacks terminating-action evidence. It cannot establish compliance, approve installation, authorize return to service or clear an aircraft for flight.
A useful owner description is therefore “linked action history and current-status evidence, with explicit applicability and counter gaps.” That tells a technical reviewer what can be examined. “All ADs closed” would replace the remaining aviation decision with an unsupported summary.