Maintenance program basis behind an owner-managed aircraft's due list

When this review is needed

• Tracking data migrated between providers at some point and interval integrity was never re-verified afterward.
• The aircraft moved between private and charter operation, and the governing program changed with it.
• The manufacturer's planning document has been revised repeatedly while the due list stayed frozen.
• A buyer or an incoming provider asked which program applies and the file offers two answers.

The problem

An owner-managed aircraft accumulates program history in layers: the manufacturer's schedule at delivery, edits by each successive management company, perhaps a charter operator's approved program for a few years in the middle. Each transition rewrote parts of the tracking database. What remains is a due list that is an artifact of those edits, with no single document stating the basis it should reconcile to.

What gets reviewed

• Identification of the controlling program, its revision level, and its applicability to this serial
• Comparison of due-list intervals against the controlling document, by sample or in full
• Deviations, escalations, and shortened intervals traced to the approvals behind them
• Migration events examined for dropped, duplicated, or remapped tasks
• One-time inspections and post-repair requirements confirmed present on the due list
• Provider program statements reconciled against the basis the database actually implements

What gets validated

• Each sampled task interval equals the controlling document at the revision in force
• Requirements added by AD action, SB election, or repair data appear as tracked tasks
• Last-done values carried through each migration match the records they came from
• The utilization basis per task, whether hours, cycles, or calendar, matches the source document
• Items marked not applicable carry a recorded justification that survives scrutiny

Evidence normally required

• The current due list and a full tracking export
• Manufacturer maintenance planning documents at the relevant revisions
• Approved program documents covering any charter or commercial period
• Bridging or migration records from each tracking-provider change
• Program statements and compliance summaries issued by past providers

Common discrepancies

• Calendar-based tasks converted to an hours basis during a migration, with no record of the decision
• An escalation applied fleet-wide by a former operator that this serial never qualified for
• A one-time post-repair inspection missing entirely from the due list
• A due list still built on a superseded revision of the manufacturer's schedule

What is at stake

Tasks tracked at the wrong interval produce overdue items that no report will ever flag, because the report checks compliance against the wrong number. At transfer, an EASA airworthiness review or a charter conformity check rebuilds the program at the owner's expense and on someone else's timeline. Ambiguity about the basis is also one of the fastest ways to stretch buyer diligence from weeks into months.

How the work runs

What the buyer receives

• A program-basis statement naming the controlling document, revision, and applicability
• An interval exception list with a source citation for every discrepancy
• A bridging-gap report for each migration event in the aircraft's tracking history

Who uses the output

• The incoming CAMO or maintenance control adopting the aircraft onto its system
• The owner representative answering diligence questions about program status
• The records team correcting the tracking database before handover

How the work fits into the transaction or program

Everything else in the owner-managed file review leans on this piece. Task-card and non-routine checks assume the due list is right, and the handover baseline states program status as fact, so the basis review runs first among the siblings whenever sequencing allows.

Jurisdiction-specific considerations

FAA rules give private operators latitude in selecting an inspection program, while charter operation requires an approved one, so a period under Part 135 usually means the basis changed twice. On the EASA side the AMP is approved or declared under continuing-airworthiness rules and reviewed on a cycle. An aircraft that has lived in both regimes needs its program history readable in both languages, and the review writes it that way.

Regulatory limits

The review neither approves nor amends a maintenance program and grants no escalations. Authority for the program rests with the operator, its CAMO, or the regulator as applicable. What the review supplies is the documented comparison between what is tracked and what the controlling text requires.

What this review does not cover

• Authoring a new maintenance program or AMP
• Bridging analysis for a future operator, which the findings feed but do not replace
• Verification that tracked tasks were physically accomplished, which the task-card review covers

Specific to this review

• Tracking migrations are the most common origin of interval drift: every provider maps fields differently, and unmapped tasks take defaults nobody reviews.
• A due list can show all green and still be wrong, because overdue status is only as good as the interval it is computed from.
• Basis ambiguity often traces to a past charter period, when an approved program lawfully displaced the manufacturer's schedule and nobody documented the reversion.
• The planning-document revision in force at delivery is rarely the one that applies today, and effectivity language shifts between revisions in ways that add or remove tasks.
• Buyers seldom audit intervals themselves; they hire someone who does, and unresolved drift found by the buyer's auditor costs more than the same drift disclosed up front.

Sources

Frequently asked questions

Relevant glossary terms

Related pages

Where this fits